Fieldwork Study

Rogador, Jacob IV E.

Sarael, Jenes Mae

INTROStructural Geology is the science that

deals with the study of the structures of rocks insofar as it is resulted from deformation and any other geological movements. These investigations are frequently field-based and draw on remote observations, experimental work, and computer simulations. In recent years, there has been an explosion of new technologies which allow scientists to answer questions that were once beyond their reach.

INTRO

This research and actual practical fieldwork mapping and surveying not only leads to advances in basic research, but is also relevant to society, through the exploration for natural resources and understanding of natural hazards and geological activities as well as the economical and industrial development here in the Bo. Baluyan, Malalag Davao del Sur.

OVERVIEWDavao del Sur is located in the

southeastern corner of the country's southernmost island of Mindanao, the province of Davao del Sur in the north to Sarangani Island in the south.

Malalag itself is a 1st class municipality in the province of Davao del Sur, Philippines. Malalag is strategically located in the heart of Davao del Sur and is accentuated at 6° 35' 45" North, 125° 23' 57" East.

OVERVIEWThe scope and parameters of

which the fieldwork study is being conducted is at Bo. Baluyan, Malalag, Davao del Sur. It is bounded by geographic coordinate’s 06°32’27’’ north latitude and 125°22’12.9’’ east longitude.

Hilly Landscape The landforms are composed of

hills with significant relief having crests of less than 500 meters elevation.

OVERVIEWThey are formed by warping and

folding of sedimentary rocks, tectonic uplift and geologic action and are found through the premises of the area involved. Mountains

These landforms are formed by tectonic uplift caused by stress and divided into several types of mountains including Limestone and Sedimentary. These are found throughout the area, particularly the southwest and southeast portions.

OVERVIEWPhilippine Fault Zone

OVERVIEW

Thus, the formation of faults along these areas of responsibilities is quiet observable. A thrust fault that trends southeast to northwest passes the formations of sedimentary along the Baluyan zigzag road. A thrust fault is a low angle reverse fault with the hanging wall moving upward relative to the footwall.

OVERVIEWAccording to the study done by the

Geology Students of the University of Southeastern Philippines last February 6, 2011, the region was uplifted as a result of the compressional force acting on the eastward by the Saranggani Trench towards west and the Cotabato trench towards northeast.

The andesite rocks intruding the clastic rocks are of Late Miocene age (7.25-11.61 Mya) that is younger to the sedimentary sequence which is of Late Oligocene age (23.03-28.4 mya).

PreparationPreparing for fieldworkWork PlanEquipment and Supplies

Preparing for fieldwork 

Work PlanDay 1: preliminary visiting the

areaDay2: The Practical Fieldwork

and Mapping

Field Discussionslead by Sir LoiEquipment and Suppliestape measurebrunton compass

methodologySTA No. Station Name Distance Angle of Dep. Bearing Remarks

PR Tubac Eat - - - Station Point of Reference

1 Ped. Post 20 meters 3˚ N 35˚ E Near side of the slope with riprap along right lane.

2 Near Cliff 20 meters 2˚ N 3˚ W Shaded area and near to cliff

3 Con. Site 20 meters 1˚ N 55˚ E Road cut present along mountain side.

4 Con. Site 20 meters 2˚ N 2˚ E Road cut present

5 Cliff Side 20 meters 0˚ N 40˚ W Shaded area along right lane

6 Cliff Side 20 meters 2˚ N 10˚ W The Riprap was destroyed for road widening

7 Curve Pt. 20 meters 0˚ N 15˚ W Very shaded area at nearside of the cliff

8 Peak of Curvature 20 meters 1˚ N 4˚ WWithin the 200 m. assigned. 2 fault lines were

observed.

9 Straight L. 20 meters 4˚ N 70˚ EUnshaded area at Cliff Side. 2 fault lines were

observed.

10 Fault zone 20 meters 1˚ N 60˚ EWithin the 200 m. assigned.

Unshaded area Cliff Side. Faults are observed.

findingsStructure Observed Point Observed Distance from P.O. Elev. & Dep.

Strike & Dip Remarks

Steep slope of Mountain Side Station 1 4. 43 meters 48˚ elevation Near riprap no. 22+540

Mini house at slope end Station 2 326.35 meters 19˚depression Beneath the cliff

Wide Road cuts at steep slope Station 3 5.72 meters 51˚ elevationRocks are brittle

Water gutter is present

Strata layering Mid-station 3 & 4 7.43 metersN 53˚ E(strike)54˚ N(dip)

Diagonally oriented and near to being vertical

Road cuts with layering Station 4 6.43 meters49 ˚ elevation

S 73˚ W (strike)80˚ S (dip)

Rocks are brittleWater gutter is present

And strata is diagonally oriented

Road cracks Station 5 3.25 meters N 2˚ W(strike)

3˚ N(dip)

Possibility to have road slips

Large boulder Station 6 14.04 meters 78˚ elevation On the right lane

Fault line 1 Station 7 23.33 meters N 67˚ W (strike)

45˚ N(dip)

Loosen soil stability rocks are brittleSteep slope

Fault line 2 Station 8 27.6 metersN 56˚ E (strike)10˚ N(dip)

Loosen soil stability rocks are brittleSteep slope

Fault line 3 Station 9 20 metersN 79˚ E (strike)15˚ N(dip)

Intrusion is present Loosen soil stability rocks are brittle

Steep slope

Fault line 4 Station 10 12 meters N 23˚ W (strike)

3˚ N(dip)

Loosen soil stability rocks are brittleSteep slope

Survey site

Survey Sites

Survey sitePreparing for fieldworkWork PlanEquipment and Supplies

The site at where the surveying field study and mapping is being conducted is at Bo Baluyan, Malalag Davao del Sur.

The geological formation of the area has been affected by uplift, subsidence, faulting, marine transgressions, geologic land mass movements and water erosion. Consequently, the geology of Bo Baluyan Malalag is notable in its great diversity, especially for such a relatively small area.

Survey sitePreparing for fieldworkWork PlanEquipment and Supplies

The general structure of the region is thrusted sedimentary layers and andesite bodies. The thrust fault is located at the eastern part of the Saranggani Penisula trending at NW-SE direction. Chaotic exhumation and upliftment of the rocks resulting to the formation of fault block mountains and hills. Furthermore, the intrusion of andesite body had also contributed to the upliftment of the region. Irregular bed dipping downward results the jointing of andesite and sandstone bodies.

Field sheetPreparing for fieldworkWork PlanEquipment and Supplies

The typical field sheets that are being used for professionals on the field are those plane sheets with grid lines intersecting at specified intervals. On the other hand, the pair decided to use the Engineering Field Book for the recording and gathering of data. The pages of the Field book are also gridded for an interval used in any given measurements. This is of great help for accurate plotting of the data into graphical and tabular forms. Thus, the back page of each page is design for any mathematical solutions.

samples

Sample StoragePlastic BagsSample Labels

samples

Transporting SamplesPreparing Samples for

Transport Chain of Custody

Chain of custodyArea Assigned

(Malalag Davao del Sur) Planning on the Activity

Observations on the Site

Collecting Samples

Labeling the Samples

Transporting Samples

Naming the Samples

Presentation of Samples

qualityQuality Assurance

The quality of one product must be assured to attest the credibility of it. Thus, to justify the collected samples of the pair, the pair decided to sealed in the rocks into the zip-lock bag after gathering it using the clothe as an alternative for the hand gloves. This is intentionally followed since the protocol of the fieldwork study is to re-assure always the conditions of the rock samples and that must be in good quality.

quality

Quality ControlFor the quality control, the rock

samples collected are mounted on the wooden slab where it is being covered with cellophane. Nevertheless, the samples are not allowed to be washed by waters since the accessory minerals and impurities might be affected when done.

dataData Management

Herewith, discussed the Data management done by the pair to render and justify the constructive results of the pair.

The pair designated the work among themselves. There is one assign to measure the distances and angles. And another one is to collect the data and do the documentations. After the data being gathered, the immediate transferring of it to the Engineer’s Field Book comes next.

For mathematical calculations, the data were subjected to be used for finding the other remaining data especially on the heights and angles that are not easily done by the provided instruments.

dataThen, the gathered data are reviewed before

leaving the area to re-assure that there is no single missing data.

After collecting and solving mathematically, the data are also analyzed by the pair to comprehend and give out the findings and were able to discuss what they have found out.

Lastly, the data were used by the pair for illustrating the area being surveyed and mapped at its most comprehensive and concise approach. This is needed to illustrate the current and actual scenario of the place where the field study is conducted.

Finally, the derivation and drawing out of conclusions and recommendations are being formulated based on the data being gathered and managed.

Health and Safety

The Status Co

a. Environmental Effects b. Soil Erosion and Slope

Stability

Health and Safety

Mitigative Measures

Mitigation measures to ensure the maintenance of slope stability during and after road construction have been recommended and can be incorporated into construction contracts. These include: mortared rip-rap, reinforced concrete supporting walls, and gabions. In addition, DPWH road standards constructions containing a number of provisions for slope protection are being applied to the construction of these roads. 

Health and Safety

Slope Protection Volume of soil removed during

excavation will be minimized. Slopes will be contoured to maximize natural revegetation. Riprap, gablons, and appropriate drainage structures will be provided.

conclusions

Due to elevated topography of the region, resorts, restaurants, and other socially enriching businesses is of good economic market to be established in the area. But, they must observed and consider that the mass movement may cause a tragic landslide and erosion that would trigger the lives of the people around the area of responsibility.  

Thrust faults and fault gouge is present generating the anticlinal folded structures. 

conclusions

The thrust fault is located at the eastern part of the Saranggani Penisula trending at NW-SE direction. Chaotic exhumation, upliftment and intrusion of andesitic rocks results to the formation of fault block mountains and hills. 

The presence of jointed, fractured, spheroidally and deeply weathered rocks possesses imminent danger to the traveling vehicles and human infrastructures. Rock and debris fall will mostly likely to occur. 

Bo. Baluyan, Malalag, Davao del Sur constitutes generally of interlingering of thrusted sedimentary rocks and porphyritic andesite intrusions.

references

Citations: http://tl.wikipedia.org/wiki/Malalag,_Davao_del_Sur http://www.zamboanga.com/z/index.php?title=Malalag,_Davao_del_Sur,_Phlippines http://www.google.com.ph/search?q=malalag+davao+del+sur&hl=tl&biw=1024&bih=596&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=2dKMTvHlJoGtiAfyr4DTAw&sqi=2&ved=0CD8QsAQ http://wikimapia.org/4970492/tl/Malalag-Davao-del-Sur http://en.wikipedia.org/wiki/Geologist

references

Publication:

Geohazard, Economic and Social implications of Sedimentary-Plutonic Structure of Bo. Baluyan, Malalag, Davao del Sur 

Philippines: Paving the Way to Developmenthttp://www.worldbank.org.ph/WBSITE/EXTERNAL/COUNTRIES/EASTASIAPACIFICEXT/PHILIPPINESEXTN/0,,contentMDK:22690219~menuPK:333004~pagePK:141137~piPK:141127~theSitePK:332982,00.html