11. Geophysical Survey

5/31/2018 11. Geophysical Survey

1/250

G E U S 2

Contents

1. Introduction 7

1.1 Aims and objectives of the geophysical survey........................................................71.2 The survey area ........................................................................................................7

1.3 Scope of work ...........................................................................................................9

2. Acquisition equipment and procedures 10

2.1 Geo-Sparker 200.....................................................................................................10

2.2 Side Scan Sonar .....................................................................................................11

2.3 G-880 Marine Caesium Magnetometer ..................................................................13

2.4 Multibeam EM 3002................................................................................................16

2.5 NaviPac System......................................................................................................19

2.6 QINSy System.........................................................................................................202.7 RTK Navigation system ..........................................................................................26

3. Health, Safety and Environment. 29

3.1 Safety overview.......................................................................................................30

3.2 Accidents, near miss and unsafe Acts....................................................................30

3.3 Environmental incidents..........................................................................................30

4. Survey Vessel 31

4.1 Ship configuration ...................................................................................................31

5. Survey preparation 35

5.1 Mobilisation Trials ...................................................................................................35

5.2 Positioning Systems................................................................................................35

5.3 Compass.................................................................................................................35

5.4 Bathymetry..............................................................................................................35

5.4.1 Velocity test (SVP)...............................................................................................36

5.5 Side Scan sonar......................................................................................................36

5.6 Sparker survey........................................................................................................37

5.7 Magnetometer.........................................................................................................37

6. Summery of events 38

7. Seabed Sampling 39

7.1 Grab samples..........................................................................................................39

7.2 Boreholes ................................................................................................................39

8. General geological setting in the Femer Belt area 40

8.1 Previous work .........................................................................................................40

8.2 Topography.............................................................................................................41


2/250

G E U S 3

8.3 Pre-Quaternary deposits.........................................................................................41

8.4 Quaternary deposits................................................................................................42

8.4.1 Till deposits..........................................................................................................43

8.4.2 Late glacial freshwater clay and sand.................................................................44

8.4.3 Holocene freshwater sand and clay/mud............................................................44

8.4.4 Holocene marine deposits...................................................................................45

9. Seabed sediments in the Femer Belt 46

9.1 Moraine - Glacial till. ...............................................................................................47

9.2 Late glacial freshwater clay - sand. ........................................................................47

9.3 Holocene freshwater-brackish (muddy) sand and sandy mud. ..............................48

9.4 Holocene marine sand. ...........................................................................................48

9.5 Holocene marine mud.............................................................................................48

9.6 Current-induced bedforms......................................................................................48

9.6.1 Sandwaves and megaripples..............................................................................49

9.6.1.1 Sand ribbons....................................................................................................49

10. Geological results of the survey 50

10.1 The Rdsand 2 Offshore Wind Farm..................................................................50

10.1.1 Chart D1 Survey Track Lines ..........................................................................50

10.1.2 Chart D2 Bathymetric chart .............................................................................50

10.1.3 Chart D3 Bathymetry Grid ...............................................................................50

10.1.4 Chart D4 Bathymetry 1m contour....................................................................51

10.1.5 Chart D5 Seabed sediments ...........................................................................51

10.1.6 Chart D6 Mosaic Side Scan Sonar..................................................................52

10.1.7 Chart D7 Seabed Features Chart....................................................................5210.1.8 Chart D8 Top Glacial .......................................................................................53

10.1.9 Chart D9 Top Bedrock Chart...........................................................................54

10.1.10 Chart D10 Isopach Holocene sand..................................................................54

10.1.11 Chart D11 Isopach Holocene Lake (silt-sand).................................................55

10.1.12 Chart D12 Isopach Holocene organic rich silt sand .....................................55

10.1.13 Chart D13 Magnetometer Map........................................................................55

10.1.14 Chart D 14 Geological seabed map ................................................................56

10.1.15 Chart D 15 Magnetometer and SSS target chart ............................................58

10.1.16 Chart D16 Boulder Chart. ................................................................................59

10.2 The Nysted Offshore Test Turbine area..............................................................59

10.2.1 Chart D 101 Survey Track Lines .....................................................................60

10.2.2 Chart D 102 Bathymetric chart ........................................................................60

10.2.3 Chart D103 Bathymetry Grid ...........................................................................60

10.2.4 Chart D104 Bathymetry 1m contour................................................................60

10.2.5 Chart D105 Seabed sediments .......................................................................60

10.2.6 Chart D106 Mosaic Side Scan Sonar..............................................................61

10.2.7 Chart D107 Seabed Features Chart................................................................61

10.2.8 Chart D108 Top Glacial Chart .........................................................................61

10.2.9 Chart D109 Top Bedrock Chart.......................................................................62

10.2.10 Chart D110 Geological map ............................................................................62

10.2.11 Chart D111 Boulder Chart. ..............................................................................63


3/250

G E U S 4

10.3 Archaeological objects ........................................................................................63

10.4 Magnetic data cleaning .......................................................................................65

10.5 Review and analysis of Side Scan Sonar Records from Rdsand. ...................67

10.5.1 Introduction ......................................................................................................67

10.5.2 Description of registration principles ...............................................................67

11. Seismic profiles E1 E11 70

11.1 Rdsand 2 Offshore Wind Farm area, Appendix E2 E9 .................................70

11.1.1 E2 Sparker Line RS-003.................................................................................70

11.1.2 E3 Sparker Line RS-018..................................................................................71

11.1.3 E4 Sparker Line RS-050..................................................................................71

11.1.4 E5 Sparker Line RS-075..................................................................................71

11.1.5 E6 sparker Line RS-087 ..................................................................................72

11.1.6 E7 Sparker Line RS-104..................................................................................73

11.1.7 E8 Sparker Line RS-cross-2400......................................................................73

11.1.8 E9 Sparker Line RS-crosss-6000....................................................................74

11.2 Nysted Offshore Test Turbine area E10 and E11...............................................74

11.2.1 E10 Sparker Line RS-con-30mig.....................................................................74

11.2.2 E11 Sparker lines RS-cra-60mig and RS-Cr-g-60mig....................................75

12. Conclusions 76

12.1 Conclusions for the Rdsand 2 Offshore Wind Farm area ................................76

12.2 Conclusions for the Nysted Offshore Test Turbine Area ....................................77

13. References 78

14. Appendix A: Location map.

15. Appendix B: Grab samples grain size analysis

16. Appendix C: Scansurvey multibeam documentation

16.1 Appendix C1: Patch test..........................................................................................

16.2 Appendix C2: Geoidal Considerations Rdsand ....................................................

16.3 Appendix C3: Position check Rdsand...................................................................

16.4 Appendix C4: Hans M, online setup Rdsand........................................................

16.5 Appendix C5: Hans M, bathymetric setup Rdsand...............................................

17. Appendix D:

17.1 Thematic maps Rdsand 2 Offshore Wind Farm...................................................

17.1.1 D1: Survey Track Lines .......................................................................................

17.1.2 D2: Bathymetric Chart .........................................................................................

17.1.3 D3: Bathymetric Grid ...........................................................................................

17.1.4 D4: Bathymetry 1m contour.................................................................................

17.1.5 D5: Seabed sediments ........................................................................................

17.1.6 D6: Mosaic Side Scan Sonar...............................................................................


4/250

G E U S 5

17.1.7 D7: Seabed Features Chart.................................................................................

17.1.8 D8: Top Glacial Chart ..........................................................................................

17.1.9 D9: Top Bedrock Chart........................................................................................

17.1.10 D10: Isopach Holocene sand...............................................................................

17.1.11 D11: Isopach Holocene Lake (silt-sand) ............................................................

17.1.12 D12: Isopach Holocene organic rich silt sand..................................................

17.1.13 D13: Magnetometer Map.....................................................................................

17.1.14 D14: Geological seabed map..............................................................................

17.1.15 Chart D15: Magnetometer and SSS target chart ................................................

17.1.16 D16: Boulder Chart..............................................................................................

17.2 Thematic maps Nysted Offshore Test Turbine Area ..............................................

17.2.1 D101: Survey Track Lines ...................................................................................

17.2.2 D102: Bathymetric Chart .....................................................................................

17.2.3 D103 Bathymetry Grid .........................................................................................

17.2.4 D104 Bathymetry 1m contour..............................................................................

17.2.5 D105: Seabed sediments ....................................................................................

17.2.6 D106: Mosaic Side Scan Sonar...........................................................................

17.2.7 D107: Seabed Features.......................................................................................

17.2.8 D108: Top Glacial Chart ......................................................................................

17.2.9 D109: Top Bedrock Chart....................................................................................

17.2.10 D110: Geological seabed map ............................................................................

17.2.11 D111: Boulder Chart............................................................................................

18. Appendix E: Seismic examples

18.1 E1 Location seismic examples................................................................................

18.2 E2 Sparker line RS-003...........................................................................................

18.3 E3 Sparker line RS-018...........................................................................................

18.4 E4 Sparker line RS-050...........................................................................................

18.5 E5 Sparker line RS-075...........................................................................................

18.6 E6 Sparker line RS-087...........................................................................................

18.7 E7 Sparker line RS-104...........................................................................................

18.8 E8 Sparker line RS-cross-2400...............................................................................

18.9 E9 Sparker line RS-cross-6000...............................................................................

18.10 E10 Sparker line RS-con-30mig..........................................................................

18.11 E11 Sparker line RS-cr- 60mig ..........................................................................

19. Appendix F: Existing vibrocores

20. Appendix G: Side Scan Sonar boulder target list

21. Appendix H: Side Scan Sonar target list

21.1 Appendix H1: Side Scan Sonar target list and documentation ...............................

21.2 Appendix H2: Complete list of Side Scan Sonar targets ........................................

22. Appendix I: Magnetic anomalies


5/250

G E U S 6

23. Appendix K: Proposal for vibrocore sampling


6/250

G E U S 7

1. Introduction

1.1 Aims and objectives of the geophysical survey

DONG Energy (Previous ENERGI E2) was awarded the concession for the Rdsand 2

Offshore Wind Farm in 2005 by the Danish Energy Agency. The installed capacity of the

Wind Farm of approximately 215 MW will be exported to a connection point on land via a

submarine cable. For the development of project a geophysical survey of the Wind Farm

area has been conducted by The Geological Survey of Denmark and Greenland (GEUS) in

May - June 2006. The brief objectives of the survey include for the Rdsand 2 Offshore

Wind Farm Area and the Nysted Offshore Test Turbine Area but are not limited to:

To provide data for the ongoing environmental statement and the subsequent

technical development on a various number of different subjects.

To provide an accurate hydrographical chart of the potential development areas

To map seabed features within the potential development areas including natu-

ral features and artefacts, obstructions and Ship Wrecks.

To provide broad-based seabed classification of surface sediments for final de-

sign of a baseline benthic survey.

To provide information on the shallow geology. Map variations in thickness of

loose or mobile sediment cover, assessment of sand waves, dunes.

To identify and locate any existing cable, pipelines, boulders, unexploded ord-

nance or other features that may impact on foundation or cable installation.

To provide information and locate any existing ripples, boulders, visible fishing

activities, inclinations or other features that may impact on foundation installation.

To provide information on the geology of soil interfaces. Map variations in thick-

ness of soil interfaces and provide information for the archaeological assess-

ments of the area.

1.2 The survey area

The Rdsand 2 Offshore Wind Farm survey area is located to the west of the Nysted Off-

shore Wind Farm. The area covers approximately 80 km2with an overall length of 13km

from east to west and a width of 6km from south to north. The listed points defining a set of

UTM zone 32 coordinates (Euref89) limit the Wind Farm area.

Point # UTM Easting UTM Northing

N1 659882.86 6052370.17

N2 661793.09 6051287.77

N3 670429.36 6050599.18

N4 670661.13 6044574.50

N5 658082.16 6048043.70


7/250

G E U S 8

Furthermore an area to the south of the Nysted Offshore Wind Farm, called the Nysted

Offshore Test Turbine Area, has been mapped. This area covers approximately 3 km2with

an overall length of 7 km from east to west and a width of 0.25 km from south to north, see

figure 1. Inside this area a cable corridor connecting the Rdsand 2 Offshore Wind Farm

and Nysted Offshore Test Turbine Area with the original Nysted Offshore Wind Farm have

been surveyed. The listed points defining a set of UTM zone 32 coordinates (Euref89) limit

this area.

Point # UTM Easting UTM Northing

N6 659882.86 6052370.17

N7 661793.09 6051287.77

N8 670429.36 6050599.18

N9 670661.13 6044574.50

N5 658082.16 6048043.70

Figure 1. Overviewmap of Rdsand 2 Offshore Wind Farm and Nysted Offshore Test Tur-

bine Area, red area.


8/250

G E U S 9

1.3 Scope of work

This report presents the final results of the programme of shallow seismic reflection acqui-

sition, Side Scan Sonar and Magnetometer acquisition in the Rdsand 2 Offshore Wind

Farm and the Nysted Offshore Test Turbine Area, South of Lolland (Figure 1 and Appendix

A1). The objective of the investigations was to map the seabed and the subsoil in both ar-

eas.

The Geophysical survey and the seabed sampling were carried out during the period 2006-

05-30 to 2006-06-15.

In order to be able to evaluate the seabed in the Wind Farm area, a geophysical survey

was carried out, including a variety of instruments, Sparker, a Benthos Side Scan Sonar,

Marine Caesium Magnetometer and a Kongsberg EM 3002 Multibeam.

The knowledge of the seabed surface sediments and the subsoil has been achieved with

this combination of data acquisition systems, supplemented by 20 grab samples, collected

in the Rdsand 2 Wind Farm Area.

To be sure to get a proper seismic penetration (>25m) it was decided to use a Sparker sys-

tem with high power. That gives a seismic resolution in the order of 0.5m.

During all the survey activities, a RTK navigation system with a vertical resolution at less

than +5cm and with an accuracy of < 1m X Y direction was used.

The NaviPac software system has been used for acquisition of navigation data and offsets

of instruments and the QINSy acquisition have been used for the bathymetric survey.

The geophysical survey and the seabed sampling were done by GEUS, while Dansurvey

has assisted GEUS with the Multibeam survey. During the project Dansurvey has changed

the organisation, and a new company, Scansurvey, has been established but the overall

responsibility is still at Dansurvey.


9/250

G E U S 10

2. Acquisition equipment and procedures

2.1 Geo-Sparker 200

The Geo-Spark series is a new generation of very high-resolution multi-tip sparkers and HV

pulsed power supplies, developed and manufactured by Geo-Resources Instruments (Fig-

ure 2).

It has been designed for operation with the Geo-Spark 1000 Pulsed Power Supply using

the Preserving Electrode Mode. In this patented mode the electrodes are negative with

respect to the frame (ground referenced), reducing the electrode wear to practically zero.

The Geo-Spark 200 source system is capable to acquire very high-resolution seismic pro-

files of the "shallow" sub-bottom strata. Depending on the energy level, the geology andwater depth, the effective penetration can exceed 300 - 400 ms below seabed.

The standard Geo-Spark 200 very high-resolution seismic spread typically consists of

Geo-Spark 200 Sparker source c/w cable and patch panel

Geo-Sense dedicated high resolution single channel streamer

Geo-Spark 1 kJ solid state pulsed power supply

Array Depth: Adjustable from 10cm to 40cm below surface

Array Geometry; Planar configuration of 0.75 x 1.00m for enhanced downward projection

of acoustic energy

Number of active Electrode Modules(1 - 4) corresponding to 50, 100, 150, or 200 tips

can be selected onboard

Electrode Modulescan be used with:

Small diameter tip, surface = 0.45 mm2, for low power per tip

Large diameter tips, surface = 2.50 mm2, for high power per tip

Energy Level: Recommended max energy per tip in PE mode:

3 Joule / tip for small diameter tips

12.5 Joule / tip for large diameter tips

Standard Configuration

For use with the Geo-Spark 1000 PPS, a combination of 2 modules with 50 small diametertips plus 2 modules with 50 large diameter tips

Primary Pulse Length: Around 0.5 ms

Dominant Frequencies: Between 500 - 2000 Hz, depending on the selected energy level

PE Mode

The Geo-Spark 200 Multi-tip Sparker is specifically designed for operation with the Geo-

Spark 1000 High Voltage Pulsed Power Supply in Preserving Electrode Mode. In this pat-

ented mode, the electrodes have negative potential with respect to the frame (ground refer-

enced).


10/250

G E U S 11

Figure 2. Sparker System

2.2 Side Scan Sonar

The Benthos SIS-1600 Series Side Scan Sonar is a fully integrated system that uses both

advanced Chirp and conventional continuous wave (CW) technologiessingle frequency

or dual frequencyand an advanced high-speed communications link to acquire high reso-

lution sidescan sonar images (Figure 3).

The Benthos SIS-1600 is a complete side scan sonar survey system that includes a topside

acquisition system and software, a 100-meter tow cable, the CL-160 Communications Link,

and one of two available tow vehicles: the TTV-196 Tow Vehicle, which acquires long

range, high resolution Chirp side scan sonar images in a single frequency band; and the

TTV-196D Tow Vehicle, which acquires long range, high resolution Chirp side scan sonarimages in two frequency bands simultaneously.


11/250

G E U S 12

Figure 3. Benthos Side Scan Sonar.

System Highlights

CL-160 Communications Link

100 kHz, 100 meter range

400 kHz, 100 meter range

Topside sonar processor

System Features

The TTV-196D Tow Vehicle includes the transceiver electronics, the processing and com-

munications electronics, the port and starboard side scan transducer arrays, the pitch, roll

and heading sensors, and the optional sensors. The optional sensors include a water tem-

perature sensor, a pressure sensor, a magnetometer, and a responder. Hydro dynamically

stable tow vehicle with operating depth up to 1,750 meters.

Features

Dynamic range - high frequency data up to 150 meters

Enhanced resolution

Repeatable transmitted waveforms

Constant temporal resolution

The pulse characteristics are programmable

Stainless steel construction

Seaconnet shipwreck, 400 kHz, 75 meter range

SYSTEM SPECIFICATIONS

Software

Application: Third party data acquisition and display (i.e.TEI Isis Lite, Chesapeake,

Sonarmap)


12/250

G E U S 13

Operating System: Microsoft Windows XP Professional

Hardware

Processor CPU: Intel Pentium 4 processor

Memory: 512 DDR SDRAM

I/O Ports: Wireless keyboard/mouse

RS-232 serial

Parallel

Ethernet 10/100 BaseT

Graphics Processor: Integrated high resolution graphics

Data Sorage: High capacity hard drive, CD/DVD-RW drive

CL-160 Communications Link

Physical Characteristics

Construction: 316 stainless steel

Dimensions: 11.4 cm (4.5 in.) outside diameter by 177.8 cm (70 in.) long

Weight in Air: 34 Kg (75 pounds)

Weight in Water: 25 Kg (55 pounds), approx.

Operating Depth: 1,750 meters

Towing Speed: 1 to 8 knots operational

Input Power: 144 VDC, 32 watts nominal

Side Scan Sonar

Acoustic Source Level: +225 dB re 1uPa @ 1 meter

Range: 25 to 500 meters each channel

Frequency Range

Chirp Frequency Range:

(TTV-196D): Simultaneously sweeps in the 110 kHz to 130 kHz and 370 kHz to 390 kHz

bands

CW Frequency

(TTV-196D): Simultaneous 123 kHz and 383 kHz

Transducer Radiation

(TTV-196D): 0.5 degrees horizontal, 55 degrees vertical (110 kHz to 130 kHz band), 0.5

degrees horizontal, 35 degrees vertical (370 kHz to 390 kHz band)

2.3 G-880 Marine Caesium Magnetometer

The Geometrics high resolution marine Caesium magnetometer system has been used for

this survey. It has simultaneous readings may be obtained from up to 6 individual sensors

through cable lengths to 2500 ft. System features include very high sensitivity measure-

ments of total field and gradient combined with rapid sampling.

A Larmor counter provides direct connection to a host CPU for integrated Side Scan Sonar.

The G-880 is completely digital, unaffected by shipboard noise, easily deployed and simple

to operate.


13/250

G E U S 14

A key element in the high performance of the system is the conditioning and the counting of

the Larmor signal. Using a proprietary design mounted into the electronics pressure ves-

sel, sensitivity, measurement rates, number of sensors and data format are selected by

commands from the vessel. Counters from multiple sensors may be concatenated together

to provide a sequential stream of RS232 data for transmittal through the tow cable.

Figure 4. G-880 Magnetometer.

Features

Sensitivity 0.02nT at 10 samples per second - selectable.

Multi-sensor gradiometer arrays for precise search or diurnal corrected total field.

Quick-connect integration to Side Scan Sonar systems with simultaneous data dis-

play.

Tow cable lengths to 2500 ft. - digital data immune to shipboard noise.

Petroleum - oceanographic - or search surveys.

Technical

Operating Principle: Self-oscillating split-beam Caesium Vapour (non-radioactive Cs133)

with automatic hemisphere switching.

Operating Range: 17,000 to 100,000 nanno Tesla (nT)

Heading Error: +/- 0.5 nT

Sensitivity: 90% of all readings will fall within the following Peak-to-Peak envelopes:

1. 0.05nT at 0.1 sec cycle rate



Operating Zones: For highest signal-to-noise ratio, the sensor long axis should be ori-

ented at 45o, +/- 30oto the earth's field angle, but operation will continue through 45o,

+/- 35o.

Gradient Tolerance: > 500nT / inch; >20,000nT / meter.

Three wire RS232, magnetic, up to 6 A/D channels for other sensors if present.


14/250

G E U S 15

Larmor Counter:

1. Integrated into sensor electronics in 'fish'

2. Ref Osc: Nominal 22 MHz

3. Output data concatenated with other counters or data sources if present

4. A/D converters: 3 single and 3 differential, 12 bit resolution.

Control functions: Keyboard commands from surface

Tow Cable:

1. Shielded twisted pair of #12 conductors with 8 separate #20 conductors

2. Strain member: Kevlar, 10,000 lbs breaking strength

3. Maximum working load: 1250 lbs

4. Outside diameter: 0.65 inch

5. Bending diameter: 24 inch

6. Weight: Air: 215 lbs per 1000 ft. Water: 70 lbs per 1000 ft

lengths selectable to 2,500 ft (762 meters)

Power Supply:

1. Converts 115/220 50/60Hz AC to 28 to 32 VDC, 150 W

2. Provides cable junction for power & data

8 x 9 x 4.5 inches, 6 lb

Environmental:

1. Operating / Storage Temperature: -45oC to +60oC (-40oF to +140oF)

Depth: Pressure vessels in 'fish' rated to 4,000 ft (increased depth possible upon

request)

Sensor 'Fish':

1. Heavy duty filament wound fibreglass, free flooded with stabilizer ring-fin assembly

2. Length:83 inches (cable stiffener and bulkhead termination adds 16 inches to length

3. Body outside diameter: 4.5inches

4. Ring-fin outside diameter: 14.25 inches

5. weight in air: 38 lbs; in water: 12 lbs


15/250

G E U S 16

2.4 Multibeam EM 3002.

The used system is a high resolution Kongsberg EM3002D dual head seabed mapping

system. Each head delivers a 1.5beam for transmission and reception, where the swath

coverage of the dual head system can reach up to 10 times the water depth. In the high

density mode of operation each head acquires up to 254 soundings per ping. The operatingfrequencies are 293 and 307 kHz to avoid interference between the two heads. The opera-

tion range of the system is from 1m to 150m, which is also a function of salinity and tem-

perature. The depth resolution is very high (~1cm), the across track measurement accuracy

is a function of depth and the distance from nadir position, a nominal range resolution of

5cm is reported (Figures 5 and 6).

Figure 5. Schematic diagram of Multibeam system operation.


16/250

G E U S 17

Figure 6. The Kongsberg EM3002D side mounted at the survey vessel M/S Hans M.

Technical Specifications

Overall specifications per Sonar Head

Frequency: 293, 300 or 307 kHz

Maximum ping rate: 40 Hz

Number of beams per ping and sonar head: 160

Number of soundings per ping and sonar head: Up to 254

Beam width: 1.5 x 1.5 degrees

Beam spacing: Equidistant or equiangular

Coverage sector: 130 degrees per sonar head

Transmit beam steering: 15 degrees in 0.5 degrees steps along track

Depth resolution: 1cm

Pulse length: 150 s

Range sampling rate: 14, 14.3 or 14.6 kHz (5 cm)

Beam forming method: Time delay with dynamic focusing in near-field.

Data storage rate: 50 to 400 MB/h (max at about 5-10 m depth)

Frequencies of 293 and 307 kHz are used in dual Sonar Head systems.

Receive beam width is inversely proportional with the cosine of the beam pointing angle

with respect to the Sonar Head (i.e. beam width is 2.1 at 45 beam pointing angle and

3.0 at 60).

Interfaces

Serial lines with operator selectable baud rate, parity, data and stop bit length for:

- Motion sensor (roll, pitch, heave and optionally heading) in format supported by sensors

from Applied Analytics, Seatex, TSS and IXSEA

- Gyrocompass in either NMEA 0183 HDT or SKR82/LR60 format

- Positions in either Simrad 90, NMEA 0183 GGA or GGK format

- Sonar head depth in Digiquartz compatible format


17/250

G E U S 18

- External clock in NMEA 0183 ZDA format

- Sound speed sensor in AML Smartprobe format

EM 3002 / Base version

28 855-164929 / B

Interface for a 1 PPS (pulse per second) clock sync signal

Ethernet and serial line interface for input of tide and sound speed data and output of all

data normally logged to disk.

Physical specifications

Sonar Head

Diameter: 332 mm

Height: 119 mm (+27 mm for connector)

Weight: 25 kg (15 kg in water)

Pressure rating: 500 m water depth

Diameter of cable to Sonar Head: 17 mm

Connector: Subconn LPBH9F

Material: Titanium

Power: 24 Vdc, 1 A (available from the Processing Unit)

A Sonar Head with pressure rating of 1500 m water depth is available with the same speci-

fications except for height (121 mm) and a restriction in maximum swath width to 3.5 times

depth (120 angular coverage sector).

Processing Unit

Height: 177 mm

Width: 427 mm (excluding rack fixing brackets)

Depth: 392 mm (excluding handles and connectors)

Weight: 14.5 kg

Power: 115 Vac (60 Hz) and 230 Vac (50 Hz), < 250 W

Operator Station

Height: 127 mm

Width: 427 mm (excluding rack fixing brackets)

Depth: 480 mm (excluding handles and connectors)

Weight: 20 kg

Power: 115 Vac (60 Hz) and 230 Vac (50 Hz), < 300 W

LCD monitor

Height: 400 mm (excluding mounting bracket)

Width: 460 mm (excluding mounting bracket)

Depth: 71 mm (excluding mounting bracket)

Weight: 9.2 kg

Power: 115 Va

00 Series System Specifications


18/250

G E U S 19

2.5 NaviPac System

APPLICATIONS The NaviPac software is integrated navigation and data acquisition soft-

ware specifically suited for applications like:

General navigation

Hydrographical & oceanographic surveying

Geophysical & seismic surveying

Modularity

NaviPac is modularity through use of multi tasking, multithreading and networking capabili-

ties of the Windows NT, Windows 2000 and Windows XP operating system. The software

is highly flexible and user configurable and the user interface adhere to The Microsoft Inter-

face Guidelines making it very intuitive and easy to operate (See screen pictures page 20).

Navigatio set-up

The NaviPac set-up module provides geodetic parameters, navigation systems, devices,

offsets and port settings.

Device I/O drivers

A vast number of field-tested device I/O drivers are provided for most available positioning

systems, GPS/DGPS receivers, gyros, motion/attitude sensors, tide-gauges, singlebeam

echosounders, magnetometers, dynamic positioning systems, autopilots, etc. Generic I/O

drivers allow definition or customization of own device I/O drivers. Data is interfaced via

RS232, a LAN or via a digital I/O interface.

Time Synchronization

Time stamping of sensor data, incoming as well as outgoing, can be done in two ways,

either by the internal computer clock or by he PPS output available from most GPS receiv-

ers. Using the PPS output data are synchronized relative to the GPS/UTC time frame, re-

sulting in an accuracy of a few milliseconds.

Survey Planning

NaviPac allows for survey planning through quickly creation of planned survey area and

survey lines. A variety of methods for creation of survey lines is provided, e.g. by click-and-

drag (of mouse/trackball), input of survey line coordinates, offset (parallel) survey lines,

cross lines, circles, arcs etc. Survey lines can easily be adapted to fit a defined survey area.

Creation of templates allows input of other data formats.


19/250

G E U S 20

.

2.6 QINSy System

Total Hydrographic Solution!

QINSy is a turnkey solution for all types of marine navigation, positioning and surveying

activities. From survey planning to data collection, data cleaning, volume calculations and

chart production, QINSy has a seamless data flow from a large variety of hardware sen-

sors, all the way to a complete chart product. QINSy runs on a standard PC platform under

the Windows XP operating system. The software is not only independent of sensor manu-

facturer, but also hardware independent.

QINSy supports the following sensor types:

Navigation Sensors

NMEA

GPS, DGPS and RTK

Gyro's and Compasses

Range/Range, Range/Bearing, Total Stations

Motion Sensors

ARPA and AIS

LBL and USBL

Inertial and Doppler

User Defined :


20/250

G E U S 21

Bathymetry Sensors

Singlebeam and Multibeam

Mechanical Profilers

SVP and Moving SV Profilers

User Defined

Side Scan Sonar Sensors

Digital and Analog

Auto Pilot Sensors

NMEA

User Defined

Magnetometer Sensors

NMEA

User Defined

Input and Output of Generic Sensors (ana-

log, weather, rpm, environmental, etc.)

NMEA

QINSy Console

Gathering and organizing the various QINSy 7 programs in a single desktop application,

called the Console, makes navigation through the program suite at each phase of the

project. guided through the various program modules designed specifically for survey

planning, data collection, data processing and chart production. Program Managers pro-vide a complete overview of project status at each phase. The main program modules

are:


21/250

G E U S 22

Planning

On-line

Replay and SSS Processing

Processing and Data Cleaning

Survey Lines

The Line Database Manager is a toolbox for survey planning, allowing the surveyor to

manually define, automatically generate and/or import from ASCII and DXF files, the fol-

lowing line types:

Targets and Symbols

Single Lines

Survey Grids


22/250

G E U S 23

Routes

Wing Lines

Cross Lines

Data can also be exported to ASCII or DXF.

The Line Database Manager works interactively in real-time with the Online Navigation

Display where points, lines and routes can be generated right in the Navigation Display

during data ac Survey Configuration

Created at the planning stage with the Setup program, a Template Database contains all

survey configuration parameters pertinent to the project. QINSy supports most of the da-

tums, projections, US State Planes, units and geoidal models used world-wide. The tem-

plate contains vessel shapes, administrative information, as well as vessel offsets and

I/O parameters. It is a complete reflection of your current survey set up, and fully editable

to kick-start your next project.

Real-Time Final Results - Data Collection and Output

Raw Sensor Data

All raw sensor data is logged and permanently stored in a fast relational database (*.db)

to which the entire survey configuration is copied from the template. Raw data can be

analysed and edited using the Analyse program, making it ready for the Replay program

and generation of new results if that is necessary. Results data (X,Y,Z and attributes) is

stored to one of several formats, primarily the QPS internal format (*.qpd), but also to

ASCII, FAU or Helical SDS format.

Data Storage

How raw and results data files are split up during acquisition is your choice. Data may be

stored on a line-by-line basis, by file size, or by manual intervention. Whatever the

method, data is normally stored in several separate databases for convenience in proc-

essing.

Accurate Timing and Ring Buffers

Supremely accurate timing is imperative in many survey situations. QINSy uses a very so-

phisticated timing routine based on the PPS option (Pulse Per Second) available on almost

all GPS receivers. All incoming and outgoing data is accurately time stamped with a UTC

time label. Internally, QINSy uses so-called "observation ring buffers", so that data values

may be interpolated for the exact moment of the event or ping. Real-Time DTM Production

All computations of position are performed in 3D. In combination with RTK or real-time tide

sensors, this means that all depth observations are immediately available in absolute sur-

vey datum coordinates. This unique technique is called "on-the-fly DTM production". QPS

was the first company introducing the "delta heave" method, which means that the quality

of the final DTM is not longer affected by heave drift caused by vessel turns.


23/250

G E U S 24

Advanced Gridding Methods

For multibeam surveys, "gridding" is the predominant data reduction method. However,

achieved reduction usually comes at the cost of loss of resolution. In QINSy there are two

gridding methods, namely;

An irregular gridding method in which the size of cells created in real-time is

directly related to variation of the seafloor. In general, large cells, more appropriately

called tiles, are created in flat seabed conditions and small tiles created in feature rich

areas with slopes, wrecks, rocks, and sand ripples. This on-the-fly method effectively

reduces the volume of data without loss of resolution.

A regular multi-level gridding method. Based on the minimum cell size, 5 addi-

tional grids are generated on-the-fly. Grid file size is no longer an issue, since there is

no limit to the number of grid cells. If the minimum cell size is selected to be 1 x 1 me-

ter, then automatically the following grid levels are being generated:

2 x 2

4 x 4

8 x 8

16 x 16

64 x 64 being the overview level

This grid can be used not only for bathymetry, but also for SSS Mosaicing, magnetometer

data, seabed classifications, etc.

Both methods provide maximum flexibility in data acquisition since there is no longer any

need to pre-define grid boundaries.

XYZ Data

Reduced point data output to tiles is accompanied in parallel with output of allsound-

ings to a second file (*.qpd, *.sds, *.fau, *.pts or other).

Either reduced or full datasets are available for further DTM processing.

Processing - Validation, Editing, Calibration, Tide Reduction

Data Cleaning and Filtering

Applying various filters and corrections for motion, tide and refraction, QINSy is designed

to output almost final results at the time of data acquisition. Moreover, the many quality

assurance functions equip the surveyor with tools to qualify results data in real-time.

Starting with cleaner and thinned data, effectively reduces time spent in post processing.

XYZ Attributes

All X, Y, Z and attributes are stored during data acquisition in a fast database, with the

following attributes attached to each point:

Identification (vessel name, system type, ping number, beam number, etc.)


24/250

G E U S 25

Status (accepted, rejected, filtered, manually edit, etc.)

Backscatter

Full 3D Geo-Referenced Side Scan Sonar (Snippet)

User Defined On-line Flags

Quality Parameters

QINSy Processing Manager

All XYZ files are listed in the QINSy Processing Manager, tabulated against a history of

processes performed on each file. This provides a complete overview of the project proc-

essing status. Processing programs are launched from the Processing Manager:

The Tide Definition and Processing utility supports various methods for tidal re-

duction.

The Validator supports both manual and automated data cleaning including ad-

vanced 3D splined surface cleaning

The QINSy Validator

Multibeam exploded the volume of point data and created data handling challenges both at

the acquisition and processing phases. The Validator has 4 different views, 3 of which can

be opened simultaneously:

Plan View

Cross View

Profile View

3D View


25/250

G E U S 26

Multibeam Calibration

Multibeam calibration with QINSy is inter-active and very easy. The Validator offers tools

to calibrate for errors in:

Roll

Pith

Yaw

Timing

Single beam and Multibeam Data Editing

Editing of single beam or Multibeam data. A variety of automated cleaning algorithms are

available:

Apply On-line Flags

Clip Below / Clip Above

Adaptive Clipping

Median and Mean

Butterworth

3D Spline Surface Despiker

Multiply/Shift

The Validator adds fully automated pipeline detection features, such as:

Top of Pipe Detection

Bottom of Trench

Mean Seabed Detection

2.7 RTK Navigation system

An AD Navigation DC202 GPS/GLONASS L1/L2 RTK long range receiver was used for

the survey.

The RTK receivers provide real time positioning data at the 1cm level while attaining thehighest reliability and stability possible. Seamless Combination GPS and GLONASS is

the heart of the AD Navigation DC-202 RTK receiver. By seamlessly combining the GPS

and GLONASS system, the RTK receivers access the total of 40 positioning satellites.

During normal operation, the receiver track 30-50% more satellites than does a GPS-only

system. Using diversity receiver techniques (dual antenna system), reception of the UHF

signal is significantly improved compared to normal systems, even under difficult radio

conditions.

The base station sends CMR corrections at up to 5Hz. The diversity receiver technique, in

combination with high update rate of CMR correction broadcasts, results in operational

RTK up to 80 kilometres from the RTK base station. With two GPS/GLONASS antennas


26/250

G E U S 27

installed, accuracies of 0.01 deg are achieved at 10 times per second. The unit contains no

moving parts, and neither calibration nor maintenance is needed.

Technical specifications

Tracking: 20 Channel Dual Constellation (DC) GPS/GLONASS L1/L2

Cold start: < 60 secondsWarm

start: < 10 seconds

Reacquisition: < 1 second

Processing: Co-op Tracking and Advanced Multipath ReductionDC200 Series RTK Posi-

tioning1 and Heading

Accuracies2:Horizontal: 1 cm + 0.15 ppm RMS

Vertical: 1.5 cm + 0.15 ppm RMS (DC201/202)

Heading: 0.01 degrees RMS (DC202 only)Update Rate:

Positioning: 5Hz (DC201/202) 20Hz

Optional Heading: 10Hz (DC202 Only) 20Hz

Optional RTK Initialisation1: Typically 10-30 seconds

Operating Range3: Up to 80 km

Built-in UHF Radio

Modem: Frequency Range: 380-470 MHz25 Khz

Channel Separation19,200 bps on Air Transmission

Diversity Reception (Dual Antenna System)

Timing: External PPS Output PPS to TTL converted to RS232 Interrupt

Signal Output formats: GPS based NMEA-0183

Messages Proprietary ASCII and Binary

Output Formats CMR/RTCM, Differential Corrections

Input Formats: CMR/RTCM, Differential Corrections

Accessories: GPS/GLONASS L1/L2

Marine Antenna AC and DC Power Cables DB 9 Serial Cables Physical specifications

Power input: 12-28 VDC or 110-230 AC


27/250

G E U S 28

Size: 2U 19 rack unit, 254 mm (d), 89 mm (h)Weight: 4.8 kg

Environmental: Vibration, EMI: EN 60945

Temperature: Operation: -20 to 55oC

Storage: -40 to 70oC

Communications: 4 x RS232 com ports, DB9, 115,200 bps1 x RS232 TTL, DB91 x PPS

output, BNC-F1 x GPS antenna input, TNC-F (N optional) 2 x UHF antenna input, TNC-F

(N optional)

1 Performance is dependent on GPS/GLONASS satellite geometry, environment, iono-

sphere conditions and distance to the base station

2 Antenna separation > 10 meter

3 Operating range is depending on availability of differential correction dataNote: Specifi-

cations subject to change without notice.


28/250

G E U S 29

3. Health, Safety and Environment.

GEUS undertake full responsibility to provide for the safety, security and health of GEUS'

personnel and to observe the respective laws and regulations of the area of operations.

GEUS tries continuously to improve the safety management skills of its personnel bothashore and aboard ships, including preparing for emergencies related both to safety and

environmental protection. The target is zero level for injury, accidents, and lost time. The

target is further to eliminate or control hazards by risk management at all workplaces.

GEUS covenants, warrants, and represents that its personnel and the personnel of its sub-

contractors are suitably trained to safely perform the service. The objectives of GEUS

Safety Management Manual are achieved by:

Senior Management ownership of a Health & Safety Culture achieved by visible in-

vestment in GEUS personnel.

Maintaining high standards of safety consciousness, personal discipline and indi-

vidual accountability by adherence to a comprehensive and documented system of

training.

Actively promoting employee participation in measures aimed at improving safety

and protecting the environment including the right to stop work should the opera-

tional risk be found unacceptable. .

Communications to personnel of known or potential hazards that may affect them-

selves, their colleagues, the ships equipment or the environment.

Continuously reviewing all Health, Safety & Environmental mandatory rules, regula-

tions, industry codes and guidelines that are relevant to our work sites, and busi-

ness.

Providing operational and health risk assessment.

Maintaining a schedule of workplace auditing

All employees are required to comply with Safety and Pollution Prevention Regulations and

Procedures at all times and to take the necessary precautions to protect themselves, their

colleagues, the ship, its equipment, and the environment.

GEUS provides external assessed comprehensive safety training for its marine personnel

as follows:

Personnel Survival Techniques

Fire prevention and fire fighting

Elementary first aid

Personal Safety and social responsibilities


29/250

G E U S 30

3.1 Safety overview

There was one Safety Instruction meeting on board the ship before it left Gedser for the

testing of equipment. The survey crew was instructed on the safety rules on board the ship.

With crew change, new instructions were performed.

3.2 Accidents, near miss and unsafe Acts

Accidents

There were no accidents during the survey.

Near miss

There were no equipment miss reports during the survey.

Unsafe Acts

There were no unsafe acts reported.

Minor incidents.

There were neither equipment minor incidents reported nor personal minor incident.

3.3 Environmental incidents

There has been no environmental incident during the survey.


30/250

G E U S 31

4. Survey Vessel

4.1 Ship configuration

The seismic survey and seabed sampling campaign included one ship - M/S Hans M (fig-

ure 7). It was used for the combined shallow seismic, side scan and Multibeam Survey.

M/S Hans M was hired by Esvagt, Esbjerg.

Figure 7. M/S Hans M.

The survey configuration at M/S Hans M is shown in Figure 8. Navigation was carried out

by RTK DGPS connected to the NaviPac Navigation Acquisition computer distributing navi-

gation data corrected for offset to the ISIS Side Scan data acquisition computer, Delph

Seismic data acquisition computer and through QINSy, the Multibeam acquisition system

which is connected to the sound sources in the water, via the individual power transmitters.

A RTK GPS system with high accuracy in x, y and z is used. No tidal correction data are

used during the survey.


31/250

G E U S 32

Figure 8. Acoustical equipment onboard M/S Hans M (not in scale).

The location and offsets of the acoustical equipment onboard M/S Hans M is shown in fig-

ure 8.


32/250

G E U S 33

The Multibeam system was side mounted on M/S Hans M and the Side Scan sonar, the

Sparker catamaran and streamer and the Magnetometer was towed behind.

The Multibeam dual head Sonar system was side mounted with the GPS reference antenna

on top, as shown in figure 9.

Figure 9. Multibeam acoustical equipment onboard M/S Hans M.

The side Scan System is towed behind the ship central with offsets of X=-4,6m Y=-16.7m.

The Sparker system was towed in the port site, with the catamaran offsets of X=6m Y=-

17.2m and the streamer offset of X=4m Y= -15.2m as shown on figure 8.

The Magnetometer is towed behind the ship central with offsets X=-2.3m Y=-48.7m.


33/250

G E U S 34

Figure 10. Sparker seismic equipment towed after M/S Hans M.


34/250

G E U S 35

5. Survey preparation

5.1 Mobilisation Trials

Checks was performed on each instrument before survey commencement to ensure that all

the sensors and processing equipment specified were functioning correctly and performing

within the manufacturer's specifications.

All checks were performed with supervision of the Employer's Representative, in order to

establish any requirements for additional calibrations and any corrections that shall be ap-

plied to the gathered data.

Calibration of the Multibeam system was conducted in presence of the Employer's Repre-sentative on the 30. May 2006. (See the attached Patch test 30052006, appendix C1)

5.2 Positioning Systems

The surface positioning system was available during all phases of the survey and it pro-

vided an absolute accuracy of better than 3m. The system is an AD Navigation DC202

GPS/GLONASS L1/L2 RTK long range system, and it is based upon the differential Global

Positioning System (DGPS). The positioning system was displayed onboard and real time

quality control was maintained.Before the mobilisation, the DGPS positioning system was checked against a calibrated

reference point in Gedser Harbour, where the antenna was located (See appendix C2) and

the control points A and B established by Rasmussen og Kragh I/S Vestensborg Alle 34

4800 Nykbing F the 30h of May 2006 on Pier in Gedser Harbour.

5.3 Compass

The vessel heading was measured by compass and logged on the navigation computer to

enable the offsets to the various fixed and towed sensors to be computed.

The compass calibration carried out alongside pier by means of coordinated points.

5.4 Bathymetry

The transducer was side mounted as described in section 4. The multibeam echo sounder

was compensated for heave in order to obtain heave corrected echo sounder records. Data

was digitally recorded and displayed in analogue form for QC purposes.

A comprehensive report on test procedures is attached in appendix C1.


35/250

G E U S 36

5.4.1 Velocity test (SVP)

During the survey, SVP tests have been carried out at least twice every day and the results

have been used for calibration of the echo sounder, if data shows change in sound velocity

in the sea, supplementary SVP was carried out (Figure 11).

Figure 11. The SVP probe is made ready for a sound velocity profile.

5.5 Side Scan sonar

A test of the side scan sonar equipment was carried out with supervision of the Employer's

Representative, in order to establish any requirements for additional calibrations and any

corrections that shall be applied to the gathered data.

The side-scan sonar was the dual frequency hydrographical sonar. It is possibly identify

objects as small as 1m in horizontal dimension i.e. boulders.

Data was recorded digitally with all data automatically referenced for position and event

data.

The system was operated at a range of 50 metres. During mobilisation the system was rub

tested and wet tested for a 15 minute period to ensure that the system is operating to the

manufacturers specifications.

The side scan sonar was tested in sea to localise seabed features at the seabed.


36/250

G E U S 37

5.6 Sparker survey

The Sparker instrument turned out to be the best suited equipment for the survey compared

to the boomer system, because the low frequency band allowed acceptable deep penetra-

tion. The system is described in detail above. It is surface towed and bedrock conditions

were determining the choice of system.

The system is capable of delineating hard and soft layers in the first 25 metres sub seabed

with a definition of 0.5-1 metres near the seabed and 1.5 metres at depth. It is understood

that penetration may be less in the event that the seabed bedrock is dense. The sparker

system has a reliable performance record, with sharp signature at input energy at 300

Joules, and be capable of operating at the maximum firing rates specified by the manufac-

turer.

All data was recorded digitally for subsequent processing and interpretation in SEGY format

and was automatically referenced for position and event data (record length shall be

150ms). Signal processing on board the survey vessel was provided, including (but not

limited to) time varying gain, band-pass filtering, stacking and heave or swell compensa-

tion.

The sparker and hydrophone was towed in such a configuration as to minimise the effects

of propeller wash, ship's noise and vessel motion, the hydrophone shall be balanced to

maximise data quality. The Employer's Representative agreed that the selected configura-

tion gives the best results.

As part of the quality control, a pulse test from the Sparker was performed in the harbour.

Prior to the commencement of reporting the seismic horizons were selected as the key

strata for reporting shall be determined in consultation between Contractor and Employer's

Representative.

A test was prepared during the start up of the survey and supervised by the Employer's

Representative

5.7 Magnetometer

The marine magnetometer was a Caesium Vapour type and capable of recording variations

in magnetic field strength during survey to an accuracy of better than 0.1nT. All measure-

ments are recorded in Gamma which is equal to nanoTesla.

The system has a repetition rate selectable between 0.5 and 10 seconds and all data was

recorded digitally via NaviPac (including sensor offset and tow depth).

Prior to commencing fieldwork, sea trials were done in an area of demonstrably low mag-

netic gradient to establish the optimum deployment location for the magnetometer, such

that vessel heading errors are less than 10 nT. The marine magnetometer data is pre-

sented as a data listing of targets determined.


37/250

G E U S 38

6. Summery of events

DATE TIME TIME LINE NAME COMMENTS

30-05-2006 05:00:00 10:58:00 Cross line Test line Cross2

30-05-2006 10:58:00 14:07:00 MB calibration PATCHTEST

30-05-2006 14:07:00 19:43:00 Gyro alignment check in Gedser

30-05-2006 20:55:00 00:00:00 RS_001-002

31-05-2006 00:00:00 08:27:00 5 lines Weather 18:00 WNW 4m/s

Cloudy

31-05-2006 08:27:00 10:10:00 Cross line

31-05-2006 10:10:00 00:00:00 17 lines Nav Problems

01-06-2006 00:00:00 05:15:00 3 lines Resurveyed due to nav. Prob.

01-06-2006 05:15:00 00:00:00 25 lines Weather: Wind 2 m/s cloudy,

02-06-2006 00:00:00 00:00:00 15 lines

03-06-2006 00:00:00 00:00:00 14 lines04-06-2006 00:00:00 00:00:00 14 lines

05-06-2006 00:00:00 00:00:00 12 lines

06-06-2006 00:00:00 00:00:00 11 lines

07-06-2006 00:00:00 11:07:00 7 l ines

07-06-2006 11:07:00 15:19:00 4 lines Connecting route 4 test mills

07-06-2006 15:42:00 16:51:00 5 lines Test mill A

07-06-2006 17:04:00 18:23:00 5 lines Test mill C

07-06-2006 18:37:00 20:09:00 5 + 1 line Test mill E

07-06-2006 20:21:00 00:00:00 5 + 3 lines Test mill G

08-06-2006 00:00:00 01:03:00 1 line Test mill G

08-06-2006 01:17:00 12:25:00 7 Lines

08-06-2006 13:04:00 16:20:00 4 cross lines

08-06-2006 16:20:00 00:00:00 14 Lines

09-06-2006 00:00:00 10:43:00 16 Lines

09-06-2006 10:43:00 18:33:00 Repair GPS Antenna

09-06-2006 18:33:00 00:00:00 4 Lines

10-06-2006 00:00:00 00:00:00 27 Lines

11-06-2006 00:00:00 00:00:00 16 Lines

12-06-2006 00:00:00 00:00:00 16 Lines

13-06-2006 00:00:00 22:40:00 22 Lines

13-06-2006 22:40:00 00:00:00 2 Gablines Closing gabs



15-06-2006 01:53:00 03:00:00 Transfer Gedser

15-06-2006 07:00:00 18:00:00 20 samples Grab Sampling


38/250

G E U S 39

7. Seabed Sampling

7.1 Grab samples

20 Seabed grab samples have been collected by GEUS on the 15 thof June during the sur-

vey. The seabed sampling have been used to determine the seabed sediment composition

and to help interpretation of the side scan sonar data, acquired during the seismic survey.

Results from the standard grain size analysis are listed in appendix B.

The median diameters of the samples are listed in table 1.

Size Classes Sample no. 1 2 3 4 5 6 7 8 9 10

Silt and clay (< 0,063 mm): 37.30 0.53 1.17 0.36 0.94 0.84 0.14 0.73 0.31 1.60

Sand, fine (0,063 - 0,200 mm): 60.18 4.95 4.52 2.21 9.05 2.96 3.55 2.59 2.25 4.89

Sand, medium (0,2 mm - 0,6 mm): 2.44 72.98 38.82 2.33 68.53 64.19 26.34 72.82 31.88 30.57

Sand, coarse (0,6 mm - 2 mm): 0.07 21.37 16.34 3.43 11.77 30.64 12.73 20.01 14.04 31.11

Gravel ( > 2 mm): 0.00 0.17 39.16 91.67 9.70 1.38 57.24 3.85 51.53 31.82

Median 0.08 0.41 0.78 - 0.38 0.46 5.18 0.43 2.43 0.77

Size Classes Sample no. 11 12 13 14 15 16 17 18 19 20

Silt and clay (< 0,063 mm): 4.34 1.25 0.34 0.58 0.97 0.34 0.28 0.39 0.85 0.41

Sand, fine (0,063 - 0,200 mm): 13.81 6.29 12.81 9.34 2.75 2.90 6.15 14.25 9.59 15.69

Sand, medium (0,2 mm - 0,6 mm): 26.84 28.16 85.06 86.79 37.29 23.99 64.74 52.41 82.17 80.27

Sand, coarse (0,6 mm - 2 mm): 8.01 8.62 1.77 2.90 22.35 44.41 26.04 20.91 6.32 1.31

Gravel ( > 2 mm): 47.00 55.68 0.02 0.39 36.64 28.36 2.79 12.03 1.07 2.31

Median 0.82 3.64 0.29 0.32 0.83 0.87 0.50 0.43 0.32 0.28

Table 1. Grain size classes and Median diameter of the seabed samples from the Rdsand

2 Offshore Wind Farm Area.

As it can be seen from table 1, the samples show a large range from silt sand to gravel.

7.2 Boreholes

No boreholes or vibrocores have been drilled during the survey of the area, but two nearby

old vibrocores have been sampled by GEUS (564037 and 564030) (Ref. 1) few hundred

meters east of the Rdsand 2 Offshore Wind Farm Area (Figure 16).


39/250

G E U S 40

8. General geological setting in the Femer Belt area

8.1 Previous work

The previous geological mapping of the Femer Belt is mainly based on a raw material

mapping project with a total of 1000km shallow reflection seismic track lines and on 41

vibrocorings carried out in April 1993.

The reflection seismic investigation is documented in a cruise report: DGU datadokumenta-

tion nr. 19 - 1992 (Ref. 1) and detailed results on grain size analysis, carbonate content and

organic content are reported in a confidential report: Rstofgeologiske og Geologiske un-

dersgelser i stersen. Femer Belt, omrde 564 (Ref.2). Additional reflection seismic

data and vibrocorings were sampled in a scientific project in co-operation with the Baltic

Sea Research Institute in Warnemnde, Germany and University of Gdansk in Poland.

These scientific investigations include investigations of sedimentology, macroplants, dia-

toms and radiocarbon ages.

Figure 12. Previous shallow seismic grid used for raw material mapping.


40/250

G E U S 41

8.2 Topography

The Mecklenburg Bay and the Eastern part of Femer Belt forms a basin area with maximal

water depths of around 30m, while Gedser Reef constitutes a threshold about 20m below

sea level. The Rdsand 2 Offshore Wind Farm is placed in the transition zone between

Femer Belt and Mecklenburg Bay, on the northern margin of the basin at water depths of 3

20m.

Figure 13. Location of the Rdsand 2 Offshore Wind Farm (western red polygon) and the

Nysted Test Turbine Area (eastern red polygon) at the northern margin of the Femer Belt

Mecklenburg Bay basin.

8.3 Pre-Quaternary deposits

The pre-Quaternary surface consists of Upper Cretaceous chalk and Paleogene marine

plastic clay. These deposits have been found in deep corings onshore (Ref. 3-6, as well as

in the GEUS ZEUS database and in the deep corings from the Femer Belt Bridge investiga-

tions (Refs. 7 and 8). The aerial distribution of the pre-Quaternary deposits has been inter-

preted in a number of maps through time summarised in the Varv map (Ref. 9) as well as

lately in connection with the onshore surface mapping (Geological Map sheet Maribo by

Klint and Rasmussen 2004) (Ref. 10). Except for a diapir structure close to Rdby it ap-

pears that the Pre-Quaternary surface consists of Cretaceous chalk in the northern part of

Lolland and Palaeogene plastic clay in the southern part. Due to a general southward dip,

the Cretaceous chalk is supposed to be about 100m below present sea-level in the Rd-

sand area and the pre-Quaternary Palaeogene plastic clay surface is supposed to be in the


41/250

G E U S 42

order of 40 - 50m below present sea level. Faulting is observed in the bedrock northern part

of Lolland with strike directions northwest southeast, while no deep faults have previously

been seen in the Rdsand survey area.

Shallow seismic investigations (ref. 2) show that weak parallel reflectors characteristic for

the plastic clay appears 30 to 50m below the present sea level between Rdby Havn and

Rdsand while a clear discordance in the Gedser region indicates chalk about 40m below

present sea level.

8.4 Quaternary deposits

The Quaternary stratigraphy is well known in The Femer Belt area (Refs. 2, 10 and 11).

Evidence have been found of 3 glacial ice streams which can be correlated to 3 individual

glacial till units the Mid Danish Till, East Jutland Till and the Belt Sea Till from the latest

glacial, Weichselian (Ref. 13). But it is only the Belt Sea Till which have been identified in

the previous shallow seismic survey (Ref. 2).

The Late and Postglacial deposits may be divided in basin deposits concentrated in the

deeper parts of Femer Belt Mecklenburg Bay and coastal deposits located in the marginal

areas shallower than 20m below present sea level. Two late glacial Baltic Ice lake phases

predates the early Holocene Ancylus Lake, followed by the final marine transgression,

which is divided in an initial brackish Mastogloia Sea phase before the Littorina marine

transgression about 8500 calendar years before present (Figure 14).

Figure 14. Seismic units (1a - W5b) mapped in Femer Belt shallow seismic survey (Ref. 2)

Calendar and radiocarbon ages are indicated. .


42/250

G E U S 43

8.4.1 Till deposits

The 3 glacial ice streams mentioned the Mid Danish Till, East Jutland Till and the Belt Sea

Till (Ref. 13) are well documented as described in (Ref. 2) but it is only the Belt Sea Till

which has been identified in the previous shallow seismic survey.

Figure 15 Deglaciation ice marginal stages during the Belt Sea deglaciation (Ref. 14).

The final deglaciation of the Weichselian glaciers during which the Belt Sea advance (Feh-

marn-Mecklenburg Vorstoss) occurred, resulted in the formation of various typically regres-

sive ice marginal features (Ref. 14) (Figure 15). One example is a glacial deformed ground

moraine in the western Femer Belt, which most likely had subsequently become part of a

marginal moraine formed along an ice lobe. North-west of this moraine a relatively soft

moraine deposit has been found apparently formed as a flow till in front of the retreating ice

margin.

The till deposits are dominating along the basin margins, at water depth of less than 15-

20m. The two different moraine deposits can be distinguished, i.e. a consolidated ground

moraine generally with a rough surface topography and an unconsolidated flow till with a

smooth surface topography.


43/250

G E U S 44

8.4.2 Late glacial freshwater clay and sand.

The further ice melting resulted in the formation of an ice- dammed lake immediately in

front of the ice margin. During this initial stage of the Baltic Ice Lake (Unit W2, Phase I)

(Figure 14), large-scale drainage systems in the form of Urstromtler'' were developed.

These were running more or less parallel with the ice margin and caused the deposition of

proximal sediments. Immediately north-east of the Gedser Reef - Darsser Sill a large sand

delta prograded in a NE direction, apparently due to melt water discharge from a late gla-

cial Warnow river system draining the area around Rostock and further inland. In the more

distal parts of the Femer Belt (as example the Rdsand area) more fine-grained and typi-

cally laminated ice lake sediments as well as layered diamict deposits accumulated. Depo-

sition of the latter type of sediments can be related to slumping processes. The end of this

episode occurred after the ice had retreated from the area, and is marked by a significant

lowering of the lake level.

A large-scale transgression of the Baltic Ice Lake occurred at the end of the late glacial

period in the south- western part of the Baltic Basin (Unit W3, Phase II, figure 14), during

which narrow connection with the open sea was formed through the Sound (Ref. 15). In the

Femer Belt and western Arkona Basin this transgressive stage is represented by varved

clay and silt deposits. Also during this stage the late glacial Warnow river system trans-

ported sediments into the Baltic Lake. The previous studies (Ref. 2) shows, that the sedi-

mentation as well as transgression level reached 20m below present sea-level, about

11.500 calendar years before present.

8.4.3 Holocene freshwater sand and clay/mud

In the following period the Baltic Sea was drained through central Sweden which caused alowering of the water level of 25m in the central Baltic. The Darss sill threshold however

dammed a local lake in the deeper parts of the Femer Belt

Associated with a further isostatic rebound, the Sweedish connection at Mount Billingen

was interrupted as well and a new episode of lake level rise (Ancylus Lake) occurred in the

Baltic basin (Ref. 15). The maximum of the Ancylus Lake in the south-western Baltic was

reached at about 10.500 calendar years before present, when the lake extended as far as

into the Kieler Bucht. In the Femer Belt area the Ancylus Lake, during this period, had a

maximum lake level about 19 - 15 m below present sea level. Studies performed along the

Swedish east coast have shown that after the Ancylus high stand period an episode of a

few hundred years occurred with drainage of the lake and a lowering of the relative waterlevel by about 9m (Ref. 15 and Ref. 16). The observations in the Femer Belt indicate a si-

multaneous lowering of the water level of not more than 5 m. This difference can be as-

cribed to the effects of the threshold north-east of Gedser Reef - Darsser Sill. Thus, condi-

tions around 10.000 calendar years before present were characterized by continuous sedi-

mentation in the deeper parts of the Femer Belt and Arkona Basin, during which the water

level in the Femer Belt area was higher than in the Arkona Basin.


44/250

G E U S 45

8.4.4 Holocene marine deposits

A further eustatic global sea level rise resulted in increasing salinities in the Great Belt and

Femer Belt area, where waters became brackish (Mastogloia Sea) and undisturbed sedi-

mentation continued in the deeper parts of Femer Belt. After the marine transgression had

reached 20m (b.s.l) hydrodynamic conditions at the Darsser Sill drastically changed due to

an around 8500 calendar years before present, rapid and marked increase of the cross-

section of this passage. As a result, current intensities strongly increased. Sedimentation

continued in the deeper basins, but coastal processes in the near-shore areas resulted in

increased erosion and long-shore transport favoring the formation of coastal barriers and

associated bar systems. The continuing transgression was associated by onshore stepping

of the coastline, which thus migrated further inland. The former coastal deposits were inun-

dated, being no longer directly affected by active coastal processes. Their remains are

presently found mainly in the form of inactive larger sand deposits.

The water exchange regime between the North Sea and the Baltic developed since the

Littorina Transgression is characterized by a non-tidal current system in which strong cur-

rents are triggered by gale-force winds or, more generally, by differences in sea level be-

tween the south-western Baltic and Kattegat. Maximum current velocities in the inflowing

saline water masses at greater depth and those reached in the out flowing low salinity Bal-

tic water at the surface are well above the critical speed required for sediment erosion. For

example, the fossil sandy coastal deposits clearly illustrate the erosional capability of this

current system by often displaying a characteristic pattern of mega ripples and sand waves.

Ripple formation in upstream direction can be ascribed to erosion of the coastal deposits,

whereas bed forms in downstream direction are positive accumulation forms.


45/250

G E U S 46

9. Seabed sediments in the Femer Belt

Figure 16. Seabed sediments in the Femer Belt area (from Ref. 17). Rdsand 2 Wind Farm

Area is located as well as the existing seismic grid (red lines) and vibrocores (red dots)

from previous raw material investigations (Ref. 2). Notice vibrocores 37 and 30 east of the

Wind Farm.

The seabed of the Femer Belt consists of Late Quaternary sediments.


46/250

G E U S 47

These sediments were mapped (Late Quaternary sediments map scale 1 : 200 000 Figure

16) within the framework of the Danish program for mapping of offshore sand and gravel

resources, which since 1990 was carried out in this area in close co-operation with Insti-

tute fr Ostseeforschung in Warnemnde.

Due to limitation of seismic resolution characterization of the seabed sediments applies to

the sediment types found at about 0.5m sub bottom depth. It is stressed that the seabed

map not only provides Iithological information, but also illustrates the regional Late Quater-

nary stratigraphy and it includes information on the depositional environment as well. Vari-

ous survey techniques could not be applied at water depths of less than about 4m, which

implies that information from the coastal zone is not included in the map.

The actual bathymetry shows water depths of around 30m in deeper parts of the Femer

Blt and Mecklenburger Bucht. A threshold, i.e. the Gedser Reef, separates Femer Belt

from the Baltic proper. A connection is formed by the Kadet Channel with a maximum water

depth of about 30m. This erosional feature extends in a NE-SW direction just south of Ged-

ser Reef. The prevailing water depth elsewhere in the Darsser Sill area is less than 20 m.

During deglaciation ground moraines were formed, whereas also flow tills and esker ice

marginal deposits were left behind by the retreating ice. Ice lake deposits accumulated in

front of the melting ice masses. These deposits can be related to the earliest stage of the

Baltic Ice Lake. After further retreat of the ice, changes of the lake water level resulted in

various episodes (Baltic Ice Lake, Ancylus Lake) during which, amongst others, a series of

littoral sediments and coastal deposits were formed in the area. Finally, the Littorina trans-

gression occurred and marine conditions were established. In course of this transgression,

another series of (marine) coastal deposits was formed.

The development described here has resulted in the typical sediment distribution as can be

observed on the seabed map. Sediments found include glacial till mostly with a thin cover

of sandy or gravely lag sediments, late glacial freshwater clay, silt or sand, Holocene

freshwater and brackish (muddy) sand and sandy mud, and Holocene marine sand and

mud.

9.1 Moraine - Glacial till.

The oldest deposits exposed in the area are till deposits dominating along the basin mar-

gins, where water depth is less than 15-20m. Two different till deposits can be distin-

guished, i.e. a consolidated ground moraine generally with a rough surface topography and

an unconsolidated flow till with a smooth surface topography. Both till deposits are being

characterized by the occurrence of a thin (approx. 0.10m) layer of lag sediments of mainly

gravel and coarser material.

9.2 Late glacial freshwater clay - sand.

The late glacial deposits consist of ice lake sediments exposed in the central part of Femer

belt and along the northern and eastern margin of Mecklenburger Bcht. Clayey and typi-

cally varved distal ice lake deposits are the most widespread late glacial surface sediments

found in the Femer Belt, late glacial sandy deposits predominate, however, in the area


47/250

G E U S 48

south of Gedser Reef. These sandy deposits reflect sediment input from a late glacial War-

now river system discharging in this area.

9.3 Holocene freshwater-brackish (muddy) sand and sandy

mud.

During the early Holocene, organic-rich fine-grained sediments were deposited in the

deeper parts of the Femer Belt area. These sediments were deposited during the develop-

ment of the Ancylus Lake and partly also during the following beginning of marine trans-

gression (Mastogloia Sea). The sandy littoral facies of these sediments in the northern part

of Femer Belt has been eroded in a narrow zone around 20 -15m water depth.

The Ancylus sediments were also deposited south and north-east of Gedser Reef filling the

older channel system and deeper parts of this area. Erosional remnants of these deposits

are locally exposed on the seafloor here.

9.4 Holocene marine sand.

Marine sand overlying moraine deposits is locally found at water depths of less than 20m.

This sand originates for a large part from former coastal deposits formed during the Lit-

torina Transgression.

Subsequently, reworking of the sandy deposits may locally have occurred.

Furthermore, at the Darsser Sill, in the vicinity of Gedser Reef and more to the east larger

areas are found, covered by an up to 4 m thick layer of sand. Water depth in these areas is

around 20 m. The thickness of the sand layer gradually decreases in an easterly direction.

9.5 Holocene marine mud.

Areas where marine mud has been accumulating are found in the central part of the Meck-

lenburger Bcht, in the Arkona Basin and in the south-western pad of Femer Belt. A charac-

teristic feature of the mud depositional area in the Femer Belt is the evidence of erosion

found in the northern and western part of this area. This is indicated by an erosional uncon-

formity and the occurrence of sediment waves. Thus, a record of continuous accumulation

of recent sediments can be expected to be found only in the central part of the Mecklen-burger Bucht.

9.6 Current-induced bedforms

The actual circulation pattern of the Femer Belt is responsible for modifying older deposits

and for the generation of specific current induced bedforms. As outlined before, the non-

tidal current system in this area is controlled by the large-scale weather pattern over NW

Europe, and more in particular, by wind-induced sea level changes in the Kattegat and Bal-


48/250

G E U S 49

tic. Another factor to be taken into consideration is the layering of the water column with

generally inflow of saline waters in the lower part of the water column and outflow of Iow

salinity Baltic water at the surface. The effect of the earth rotation (Coriolis force) further

complicates this two Iayer flow pattern.

A general conclusion is that the seabed in the southern part of the investigated area is

mainly affected by inflowing saline waters from the Great Belt and Kattegat, whereas Baltic

outflow affects the seafloor at shallower (< 15m) depth in the northern part of the area.

9.6.1 Sandwaves and megaripples.

These transverse bedforms clearly indicate current-induced sediment transport. Sand-

waves and megaripples occur in various parts of the investigated area and are often found

in relation with fossil sandy coastal deposits. In such areas they originate from erosional

processes affecting the fossil deposits upstream, whereas downstream they form by accu-

mulation processes.

Investigations of the Gedser Reef area (Ref. 18) have shown the occurrence of sandwaves

indicative both of inflow and outflow. Moreover, repeated observations indicated a change

of bed form configurations in this area, i.e. a reversal of large sandwaves as well as the

disappearance of a megaripple field (Ref. 19).

9.6.1.1 Sand ribbons.

Small sand ribbons are widespread at shallow (< 15m) depth over the entire area in the

northern part of the Femer Belt. Only in a few cases it was possible to determine the cur-

rent direction from these longitudinal bedforms.


49/250

G E U S 50

10. Geological results of the survey

The survey results will be presented in two parts:

The Rdsand 2 Offshore Wind Farm, Chart D1 D16

The Nysted Offshore Test Turbine area, Chart D101 D112

10.1 The Rdsand 2 Offshore Wind Farm

The Rdsand 2 Offshore Wind Farm area covers the area selected for installation of wind

turbines which has an overall length of 13km from east to west and a width of 6km from

south to north. For location see figure 13.

10.1.1 Chart D1 Survey Track Lines

The location of the 131 seismic track lines (RS_001 to RS_126 plus RS cross2(4000)

RS_cross 2-6000) surveyed in the Rdsand 2 Offshore Wind Farm Area is presented on

chart D1.

10.1.2 Chart D2 Bathymetric chart

The map of the sea bed bathymetry is based on multibeam measurements. Selected pointmeasurements are indicated and the topography is shown as water depth contour lines with

a 1m contour interval (m below sea level).

The bathymetric survey has given the following results:

Water depths: The depth interval is between 5.2 and 19.5m, with the shallow area located

in the northe

Documents

11. Geophysical Survey