Hydrocarbon Gases in Canned Core Samples from Leg 28 Sites 271, 272, and 273, Ross Sea

McIver, R.D.

doi:10.2973/dsdp.proc.28.128.1975

Cited by 17 publications

(20 citation statements)

References 4 publications

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“…Gas hydrates were also encountered at this site [Barrett, 1988]. Earlier reports of high canned hydrocarbon values in DSDP samples from the Leg 28 sites [Mclver, 1975] Tertiary age deposits are also exposed on King George Island and include the Ezcurra Inlet Group (Paleocene), Fildes Peninsula Group (Eocene? ), and Dufayel Island Group (Eocene).…”

Section: S Data Have Been Made Public and Described In Any Detail [Cmentioning

confidence: 76%

Geology and hydrocarbon potential of the Antarctic continental margin

Anderson

1990

Mineral Resources Potential of Antarctica

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Seismic surveys have been conducted on most of the seasonally ice-free portions of the Antarctic continental margin, but drilling has been limited to only a few areas. These data, coupled with the results of geological studies of coastal outcrops and information from the conjugate Gondwana continents, are used to infer the subsurface geology of five different sectors of the Antarctic continental margin and to assess their hydrocarbon potential. Potential source rocks are believed to exist on most portions of the continental margin and are buried deep enough, or are subjected to high enough geothermal heat, for hydrocarbon maturation to have occurred in these deposits. Suitable reservoir rocks are also considered to be widespread on the margin, with the possible exception of that portion of the Pacific-Antarctic margin situated north of the Tula Fracture Zone and including the Bransfield Basin. Structural traps are generally confined to the older sequences on the margin that fill early rift basins. Stratigraphic traps are probably common. WILKES LAND SECTOR GeologyPrior to the breakup of Gondwana, the Australian and Antarctic continents were joined along what is now the Wilkes Land continental margin of Antarctica ( Figure 2). Initial studies of magnetic data from the Indian Ocean by Weissel and Hayes [1972] led to the conclusion that seafloor spreading between Australia and Antarctica began 55 million years ago. Later, Cande and Mutter [1982] reinterpreted these data and concluded that initial rifting between the two continents had actually begun between 110 and 90 Ma, and Veevers [1986] constrained the time of breakup to 95 _+ 5 Ma. Actual breakup was preceded by an extended period of extension and rifting, which Falvey [1974] refers to as the Rift Valley Phase. This phase probably began in the mid-Jurassic [Veevers, 1987]. During this time, rift basins formed in the vicinity of the incipient breakup axis. Initially, these basins were broad troughs which developed into narrow fault-bounded basins as rifting progressed [Falvey and Mutter, 1981]. Subsidence rates on Australia's southern margin were high (an average of 0.1 km/Ma) during the rifting phase and slowed appreciably (an average of 0.01 km/Ma) during the postbreakup phase [Falvey and Mutter, 1981]. During the rifting phase, a thick sequence of mostly continental deposits accumulated in the basins of southern Australia, with periodic marine invasions from the west result-

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Section: S Data Have Been Made Public and Described In Any Detail [Cmentioning

confidence: 76%

Geology and hydrocarbon potential of the Antarctic continental margin

Anderson

1990

Mineral Resources Potential of Antarctica

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“…The presence of natural gas in the subsurface has been associated with roughly circular depressions in the seafl oorpockmarks-where natural gas has apparently escaped (King and Maclean, 1970;Hovland, 1981;Hovland and Judd, 1988), and these have been found in many regions globally (e.g., Judd and Hovland, 2007;Pilcher and Argent, 2007). These pockmarks are inferred to result from the expulsion of sub-seafl oor gas occurrences associated with the phase change from hydrate to free gas, and support the existence of extensive gas in the sedimentary section, as found on the Ross Shelf by Deep Sea Drilling Leg 28 (McIver, 1972). These results suggest an alternate interpretation for the mounds-that they are carbonate mounds (Lawver et al, 2008), similar to those seen in the Porcupine Bight off northwest Europe (Shannon et al, 2007).…”

Section: Introductionmentioning

confidence: 75%

Flat-topped mounds in western Ross Sea: Carbonate mounds or subglacial volcanic features?

et al. 2012

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“…Kvenvolden et al, 1987;Geletti and Busetti, 2011), or on geochemical records of methane and chloride content (Mann and Gieskes, 1975;McIver, 1975).…”

Section: Gas Hydrate Related Bottom-simulating Reflectorsmentioning

confidence: 99%

Did massive glacial dewatering modify sedimentary structures on the Amundsen Sea Embayment shelf, West Antarctica?

Weigelt

Uenzelmann-Neben

Gohl

et al. 2012

Global and Planetary Change

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Multichannel seismic reflection lines collected in the western Amundsen Sea Embayment (ASE) provide an insight into the sedimentary cover on the shelf, which documents glacial processes. Numerous columnar, reflection-poor structures penetrating the sedimentary sequences on the middle shelf form the focus of this study. The features range between 50 and 500 m in width, and from a few metres up to 500 m in height. The columns originate and end at different depths, but do not seem to penetrate to the seafloor. They show well-defined vertical boundaries, and reflection signals can be identified below them. Hence, we exclude gasbearing chimneys. Based on the general seismic reflection characteristics we suggest that the columns originate from dewatering processes which occur close to glaciated areas where fluids are pressed out of rapidly loaded sediments. Likely several mud-diapirs rise from water-rich mud layers within a mixed sedimentary succession and penetrate overlying denser and coarse-grained sediment strata. The presence of fluidescape veins indicates a glacial origin and overprinting of the older sedimentary sequences on the ASE. The locations of the structures indicate that grounded ice sheets reached at least onto the middle shelf during former glacial periods.

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Hydrocarbon Gases in Canned Core Samples from Leg 28 Sites 271, 272, and 273, Ross Sea

Cited by 17 publications

References 4 publications

Geology and hydrocarbon potential of the Antarctic continental margin

Geology and hydrocarbon potential of the Antarctic continental margin

Flat-topped mounds in western Ross Sea: Carbonate mounds or subglacial volcanic features?

Did massive glacial dewatering modify sedimentary structures on the Amundsen Sea Embayment shelf, West Antarctica?

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