910 Full - docs.iodp.org · 910 Full The overall scientific goal is to vastly improve our understanding of biogeochemical and physical processes that lead to widespread methane occurrence

Proponent Information

IODP Proposal Cover Sheet -

Abstract

Title

Proponents

Affiliation

Proponent

Keywords Area

Country

Received for:

Permission is granted to post the coversheet/site table on www.iodp.org

910 FullContinental Margin Methane Cycling: Rio Grande

Enormous quantities of microbial methane occur in continental margin sediments. This methane can exist as dissolved gas,free gas or gas hydrate. However, its abundance and importance remain poorly understood, because of major open issuesregarding the formation and flow of methane. These include reaction pathways and rates of microbial methanogenesis; theinfluence of sediment lithology, temperature, and organic matter composition upon methanogenesis; the relative importanceof shallow versus deep methanogenesis; the cycling of carbon and its sequestration as carbonate in the sediment; andcarbon release back to the ocean. The outstanding problems demand new drilling that enables linking microbiologicalexperiments done at near in situ conditions, a vast array of geochemical analyses, and detailed physical propertymeasurements within a framework of reaction-transport modeling. Such study would directly address Challenge 13 (Whatproperties and processes govern the flow and storage of carbon in the subseafloor?) and Challenge 5 (What are the origin,composition, and global significance of subseafloor communities?) in the IODP 2013-2023 science plan.

Widespread microbial methane implies globally relevant processes. However, past drilling clearly demonstrates a highdegree of heterogeneity in methane abundance and distribution at individual locations and between regions. This reflectsdifferences in key parameters that affect the formation and flow of methane. The Rio Grande Cone, offshore Brazil,represents a spectacular natural laboratory for understanding how carbon cycles in methane-charged sediment. Seismicreflection profiles show a prominent bottom-simulating reflector spanning ~45,000 km2. Multibeam bathymetry and near-bottom surveys display areas with pockmarks near the upper limit of the methane hydrate stability zone. Piston coresrecovered samples of gas hydrate and authigenic carbonate. Analyses of pore water and gas from these cores havedetermined shallow (~3-10 mbsf) subbottom sulfate-methane transitions related to anaerobic oxidation of methane, as wellas a microbial origin for the gas. All information indicates a large region of the seafloor with a dynamic microbial methanesystem.

We propose eight sites that sample the variation in methanogenesis and carbon cycling at different water depths(~600-3000 m) and different locations across the margin. The measurement plan consists of high-resolution sampling formicrobiology and geochemistry, extensive pressure coring, APC-T temperature measurements, infrared core imaging, anddownhole logging. Methanogenesis rates will also be measured in microbiological experiments where sediment samples areinoculated in biomass recycle reactors that reproduce the starved conditions experienced in situ and in separate incubationexperiments done under in situ pressure.

Carbon cycling in methane-charged continental margin sediments: Rio Grande Cone (Brazil)

Alberto Malinverno, Joao Marcelo Ketzer, Gerald R. Dickens, Caroline Thaís Martinho, Adolpho Augustin,Frederick S. Colwell, Verena B. Heuer, Fumio Inagaki, Adriana Leonhardt, Renata Medina da Silva, YukiMorono, Vivian Helena Pellizari, Maria Alejandra Pivel, John W. Pohlman, Brandi Reese, Luiz FredericoRodrigues, Marta E. Torres, Adriano R. Viana

microbial methanogenesis, hydrates, carbon cycle Brazil Atlantic margin

Alberto MalinvernoLamont-Doherty Earth Observatory of Columbia University, Palisades, New York, USAUnited States

⃞✓

2018-04-02

Generated: 2018-11-02T20:52:57+00:00

Scientific Objectives

Non-standard measurements technology needed to achieve the proposed scientific objectives

-910 Full

The overall scientific goal is to vastly improve our understanding of biogeochemical and physical processes that lead to widespreadmethane occurrence in continental margin sediments and that couple to the overlying ocean over time. We will determine the amount anddistribution of methane across a region where basic observations suggest that key parameters differ in space and time. The proposed studywill address outstanding questions on carbon cycling in continental margin sediments: we will estimate in situ methanogenesis rates bycomparing the results of microbiological experiments and reaction-transport modeling, test whether observations require a deep methanesource, investigate how methanogenesis rates are related to sediment type, temperature, age and composition of organic matter,characterize the time-dependent organic matter input driven by paleoceanographic changes, clarify the role of methane in the complex setof near-seafloor biogeochemical reactions relevant to the global carbon cycle, and constrain the flux of carbon from the sediment back to theocean. The planned measurements of in situ methane concentration from pressure core sampling will provide key constraints to themodeling and the estimated methanogenesis rates will inform the quantification of methane amounts in continental margin sediments.Additional benefits will include a comparison of in situ methane estimates based on N2 and Ar with PCS data, a set of combined incubationand extraction-based measurements of H2, and constraints on how methane and carbon escape the seafloor near the feather edge ofhydrate stability conditions.

Generated: 2018-11-02T20:52:57+00:00

Proposal 910-FullSite RGC-01B 2980 3000 3020 3040 3060SP:

RGC-01B

1.500

2.000

2.500

3.000

3.500

4.000

2980 3000 3020 3040 3060SP:1.500

2.000

2.500

3.000

3.500

4.000

BSR

2880 2900 2920 2940 2960 2980SP:1.500

2.000

2.500

3.000

3.500

4.000

0231_0486

2880 2900 2920 2940 2960 2980SP:1.500

2.000

2.500

3.000

3.500

4.000

BSR

RGC-01BSP 3021 on 0231_0486SP 2930 on 0277_0234

Lat -32.949807 / Long -49.879119UTM 22S 604770 E / 6353720 N

0231_0486

0277_0234 0277_0234

SW SW NE

NW SE NW SE

1km 1km

1km 1km

3145

3125

3105

3085

3065

3045

3025 3005

2995

2786

2806

2826

2846

2866

2886

2906

29

-1200

-1160

-1140

-1120

RGC-01B3005 2985

2965

2945

2925

2905

2885

2865

2906

2936

2956

2976

2996

3016

3036

3056

3076

-1100

-1080

-1180-1220

-1240

Line 0231_0486

km

0 1 2

-1220

TWT

(s)

TWT

(s)

TWT

(s)

TWT

(s)

RGC-01B

RGC-01B RGC-01B

Water depth 1160 mPenetration 500 m

Data �les will be submitted to the SSDB by the May 2018 deadline

32.9

3°S

49.90°W 49.86°W

32.9

7°S

3140 3160 3180 3200 3220 3240SP:

1.500

2.000

2.500

3.000

3140 3160 3180 3200 3220 3240SP:

1.500

2.000

2.500

3.000

3056

3076

3096

3116

3136

3156

3176

3186 3556

586

3

36

3646

3666

3686 -1280

-1260

-1180

-1160

317

3196

3216

236

3256

326

3296

3436

3456

3476

3496

3516

3536

3556

RGC-09A

7

3

3

606

26

Proposal 910-FullSite RGC-09A

RGC-09ASP 3575 on 0277_0229SP 3185 on 0277_0234

Lat -33.012018 / Long -49.808320UTM 22S 611310 E / 6346750 N

km

0 1 2

-1200 -1220

-1240

-1260

Line 0277_0234Line 0277_0229

RGC-09A

RGC-09A RGC-09A

SW NE

NW SE NW SE

0277_0234

1km0277_0234

1km

BSR

3520 3540 3560 3580 3600 3620SP:

1.500

2.000

2.500

3.0000277_0229

1km

RGC-09ASW NE3520 3540 3560 3580 3600 3620SP:

1.500

2.000

2.500

3.0000277_0229

1km

BSR

TWT

(s)

TWT

(s)

TWT

(s)

TWT

(s)



32.9

9°S

49.82°W 49.78°W

33.0

3°S

6300 6320

6340 6360

6380 6400

6420 6440

646

40

0- 1

140 6160

6180 6200

6220 6240

6260 6280

6300

40

0-

1

Proposal 910-FullSite RGC-02B

RGC-02BSP 6312 on 0277_0222

Lat -33.216336 / Long -49.664565UTM 22S 624450 E / 6323935 N

RGC-02B

km

0 1 2

Line 0277_0222

626062806300632063406360SP:1.500

2.000

2.500

3.000

3.500

RGC-02BNW SE

0277_0222

1km

626062806300632063406360SP:1.500

2.000

2.500

3.000

3.500

RGC-02BNW SE

0277_0222

1km

BSR

TWT

(s)

TWT

(s)

30

01-



Seismic re�ection data for a crossing line have been requested from Petrobras and the Brazil National Petroleum Agency

33.2

0°S

33.2

4°S

49.68°W 49.64°W

2599

2579

2559

2539

2519

2499

2479

2459

00

- 1 3

00

2739

2719

2699

2679

2659

2639

2619

2599

2579

0 0- 1 4

- 1 5 0 0

-1

40


RGC-03BSP 2597 on 0277_0090

Lat -33.628705 / Long -50.188400UTM 22S 575275 E / 6278716 N

RGC-03B

Line 0277_0090

2560 2580 2600 2620 2640SP:1.000

1.500

2.000

2.500

3.000

0277_0090

1km

RGC-03BNW SE

2560 2580 2600 2620 2640SP:1.000

1.500

2.000

2.500

3.000

0277_0090

1km

RGC-03BNW SE

BSR

TWT

(s)

TWT

(s)

km

0 1 2




33.6

1°S

50.21°W 50.17°W

33.6

5°S

1426

1446

1466

1486

1506

1526

1546

1566

1346

1366

13

86

1406

14

26

14

66

1486

15

06

0-

091-

366

1386

1406

1426

1446 14

86

1506

15

26

1546

1566

1586

1606

16

26

646

- 1 0 0 0


RGC-04BSP 1492 on 0277_0080

SP 1493 on 0277_0229 - projected wellLat -33.536711 / Long -50.368336

UTM 22S 558648 E / 6289032 N

RGC-04B

Line 0277_0080

Line 0277_0229

1440 1460 1480 1500 1520 1540SP:

1.000

1.500

2.000

2.500 0277_0080

1km

RGC-04BNW SE

1440 1460 1480 1500 1520 1540SP:

1.000

1.500

2.000

2.500 0277_0080

1km

RGC-04BNW SE

BSR

km

0 1 2

1440 1460 1480 1500 1520 1540SP:

1.000

1.500

2.000

2.5000277_0229

1km

RGC-04BSW NE1440 1460 1480 1500 1520 1540SP:

1.000

1.500

2.000

2.5000277_0229

1km

RGC-04BSW NE

BSR

TWT

(s)

TWT

(s)

TWT

(s)

TWT

(s)



Projected site location

33.5

2°S

50.39°W 50.35°W

33.5

6°S

-1000


RGC-05BSP 1487 on 0277_0086SP 1572 on 0277_0205

Lat -33.439839 / Long -50.451039UTM 22S 551026 E / 6299816 N

1440 1460 1480 1500 1520 1540SP:

0.500

1.000

1.500

2.000

2.500

TWT

(s)

0277_0086

1km

RGC-05BNW SE

1440 1460 1480 1500 1520 1540SP:

0.500

1.000

1.500

2.000

2.500

TWT

(s)

0277_0086

1km

RGC-05BNW SE

1520 1540 1560 1580 1600 1620SP:

0.500

1.000

1.500

2.000

2.500

RGC-05B

TWT

(s)

SW NE

0277_0205

1km

1520 1540 1560 1580 1600 1620SP:

0.500

1.000

1.500

2.000

2.500

RGC-05B

TWT

(s)

SW NE

0277_0205

1km

BSR

BSR

1699 1679

1659 1639

1619 1599

1579 1559

1539 1519

1479

1459

1439

1419

1399

1379 1359

1339 1319

1

-016

- 53

1539 1519

1499 1479

1459 1439

1419 1399

639

1619

1599

1579

1559

1539

1519

1499

1479

1459

- 6 9 0

016-

km

0 1 2Line 0277_0205




RGC-05B

33.4

2°S

50.47°W 50.43°W

33.4

6°S

50.39°W


RGC-06BSP 2279 on 0277_0258SP 4166 on 0277_0187

Lat -32.780872 / Long -49.889998UTM 22S 603950 E / 6372460 N

2240 2260 2280 2300 2320SP:

1.500

2.000

2.500

3.000

3.500

TWT

(s)

RGC-06BNW SE

0277_0258

1km

21

2166

2186

2206

2226

2246

2266

2286

2306

2326

39 4319

4299 4279

4259 4239

4219 4199

4179

0

-0

31

00

2-

1

2306

2326

2366

2386

2406

2426

2446

2466

4139 4119

4099 4079

4059 4039

4019

2240 2260 2280 2300 2320SP:

1.500

2.000

2.500

3.000

3.500

TWT

(s)

RGC-06BNW SE

0277_0258

1km

BSR

RGC-06B

km0 1 2 4120 4140 4160 4180 4200 4220SP:

1.500

2.000

2.500

3.000

RGC-06BSW NE4120 4140 4160 4180 4200 4220SP:

1.500

2.000

2.500

3.000

RGC-06BSW NE

BSR

0277_0187

1km

0277_0187

1km




32.7

7°S

49.91°W 49.87°W

32.8

1°S

49.83°W

Proposal 910-FullSite RGC-10A

RGC-10ASP 2140 on 0277_0270SP 4249 on 0277_0187

Lat -32.775206 / Long -49.850842UTM 22S 607624 E / 6373049 N

2100 2120 2140 2160 2180SP:

1.500

2.000

2.500

3.000

RGC-10ANW SE

0277_0270

1km

TWT

(s)

2100 2120 2140 2160 2180SP:

1.500

2.000

2.500

3.000

RGC-10ANW SE

0277_0270

1km

TWT

(s)

4200 4220 4240 4260 4280 4300SP:

1.500

2.000

2.500

3.000

3.500

RGC-10A

0277_0187

1km

TWT

(s)

SW NE4200 4220 4240 4260 4280 4300SP:

1.500

2.000

2.500

3.000

3.500

RGC-10A

0277_0187

1km

TWT

(s)

SW NE

BSR

BSR

2020

2040

2060

2080

21

00

2120

21

40

4359

4339

4319

4299

4279

4259

4239

4219

30

0-1

2140

2160

2180

2200

2220

2240

2260

4239

4219

4199

4179

4159

4139

4119

00

31

-

km

0 1 2

RGC-10A

Line 0277_0187



32.7

6°S

49.87°W 49.83°W

32.8

0°S

1

1485

1465

1425

1405

1385

1365

1345

1325 1345

1325

1305

1285

1265

1245

1225

1205

1185

12801300132013401360SP:

3.500

4.000

4.500

5.000

5.500

Proposal 910-Full

RGC-07BSP 1319 on 0228_0313

Lat -33.557135 / Long -49.100375UTM 22S 676344 E / 6285330 N

NW SE

TWT

(s)

RGC-07B

km

0 1 2

RGC-07B

0228_03131km

12801300132013401360SP:

3.500

4.000

4.500

5.000

5.500

NW SE

TWT

(s)

RGC-07B

0228_03131km

BSR

00

0-

3

00

2-

3

99

8-

2

1445




33.5

3°S

49.13°W 49.08°W

33.5

8°S

49.03°W

Site RGC-07B

3899

3879

3859

3839

3819

3799

3779

3759

3739

3719

1086

1106

1126

1146

1166

1186

1206

1226

1246

0962-

4039

4019

3999

3979

3959

3939

3919

3899

3879

966

986

1006

1026

1046

1066

1086

1106

RGC-08BSP 3873 on 0277_0090SP 1141 on 0231_0491

Lat -33.926419 / Long -49.816671UTM 22S 609375 E / 6245372 N


Line 0231_0491

RGC-08B

NW SE

TWT

(s)

RGC-08B

km

0 1 2

3820 3840 3860 3880 3900 3920SP:3.000

3.500

4.000

4.500

5.000

NW SERGC-08B

3820 3840 3860 3880 3900 3920SP:3.000

3.500

4.000

4.500

5.000

TWT

(s)

0277_00901km

BSR

0277_00901km

1100 1120 1140 1160 1180SP:

3.000

3.500

4.000

4.500

5.000

SW NERGC-08B

TWT

(s)

0231_04911km

1100 1120 1140 1160 1180SP:

3.000

3.500

4.000

4.500

5.000

SW NERGC-08B

TWT

(s)

0231_04911km

BSR

BSR

0372-



33.9

1°S

49.85°W 49.80°W

33.9

6°S

49.75°W

910 - FullProposed Sites (Total proposed sites: 10; pri: 7; alt: 3; N/S: 0)

Generated: 2018-11-02T20:52:57+00:00

Site Name Position(Lat, Lon)

WaterDepth

(m)

Penetration (m)Brief Site-specific Objectives

Sed Bsm Total

RGC-01B(Primary)

-32.94981-49.87912 1160 500 0 500

Sample a "stratigraphic" methane hydrate setting in the extensionaldomain of the Rio Grande Cone. This site will allow for investigatingmicrobial methanogenesis where fluid flow is likely not to be significantand address our scientific objectives on constraining the of microbialmethanogenesis pathway, vertical distribution, and rate, and oncharacterizing reactions at the SMTZ. This site will be also triple-coredfor a paleoceanographic reconstruction.

RGC-09A(Alternate)

-33.01202-49.80832 1218 500 0 500 Alternate site with same site-specific objectves as RGC-01B.

RGC-02B(Primary)

-33.21634-49.66456 1368 500 0 500

Sample a "stratigraphic" methane hydrate setting in the extensionaldomain of the Rio Grande Cone. This site will allow for investigatingmicrobial methanogenesis where fluid flow is likely not to be significantand address our scientific objectives on constraining the of microbialmethanogenesis pathway, vertical distribution, and rate, and oncharacterizing reactions at the SMTZ.

RGC-03B(Primary)

-33.6287-50.1884 1362 500 0 500


RGC-04B(Primary)

-33.53671-50.36834 920 500 0 500


RGC-05B(Primary)

-33.43984-50.45104 620 200 0 200

Sample a location near pockmarks on the upper slope of the Rio GrandeCone at the feather edge of the MHSZ. This site will allow fordetermining the variation in methanogenesis in a location where fluidadvection may be important and where hydrates may be activelydissociating, providing key observations on the portion of the marinehydrate reservoir that is most sensitive to climatic change.

RGC-06B(Primary)

-32.78087-49.8900 1240 500 0 500

Sample a location near pockmarks on the middle slope of the RioGrande Cone. This site will allow for determining the variation inmethanogenesis in a location where fluid advection may be important fora comparison to "stratigraphic" settings.

RGC-10A(Alternate)

-32.77521-49.85084 1290 500 0 500 Alternate site with same site-specific objectives as RGC-06B.

RGC-07B(Primary)

-33.55713-49.10038 3001 800 0 800

Sample a "stratigraphic" methane hydrate setting in the deepwatercontourite SE of the Rio Grande Cone. This site will allow forinvestigating microbial methanogenesis where fluid flow is likely not to besignificant and address our scientific objectives on constraining the ofmicrobial methanogenesis pathway, vertical distribution, and rate, andon characterizing reactions at the SMTZ. This site will be also triple-cored for a paleoceanographic reconstruction.

RGC-08B(Alternate)

-33.92642-49.81667 2710 800 0 800 Alternate site with same site-specific objectves as RGC-07B.

Documents

910 Full - docs.iodp.org · 910 Full The overall scientific goal is to vastly improve our understanding of biogeochemical and physical processes that lead to widespread methane occurrence