The Stratigraphy, Setting and Hydrocarbon Potential of the Mesozoic Sedimentary Basins of the Antarctic Peninsula
Published:January 01, 1990
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David I. M. Macdonald, Peter J. Butterworth, 1990. "The Stratigraphy, Setting and Hydrocarbon Potential of the Mesozoic Sedimentary Basins of the Antarctic Peninsula", Antarctica as an Exploration Frontier—Hydrocarbon Potential, Geology, and Hazards, Bill St. John
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The Antarctic Peninsula is a relatively accessible area of the continent, a fact which has stimulated interest in its hydrocarbon potential. This chapter uses known stratigraphic information to provide general constraints on the hydrocarbon potential of the Mesozoic basins of the Antarctic Peninsula.
The peninsula lies on a medium-sized block of continental crust. It is one of a mosaic of crustal blocks forming West Antarctica which underwent a complex tectonic evolution during Gondwana breakup. It was the site of an active volcanic arc above easterly subducting proto-Pacific ocean floor throughout the Mesozoic and part of the Cenozoic.
As a result the exposed Mesozoic basins display a complex stratigraphy, reflecting local tectonic and volcanic events. No units can be correlated between any two basins, but there are a few general trends. Almost all basins are post-Oxfordian; their fill is entirely clastic, and largely derived from the Antarctic Peninsula volcanic arc. Most basins were affected by a period of arc expansion in Late Jurassic or Early Cretaceous times, which manifests itself as inputs of lava or coarse volcaniclastic sediment. Berriasian and older mudstones are generally finer-grained and darker than mudstones from post-Berriasian strata. Deformation is variable, but rarely penetrative.
This stratigraphic information provides the basis for general constraints on the hydrocarbon potential. Organic geochemistry shows that Berriasian and older mudstones from the backarc region are the best potential oil source rocks; all other mudstones tend to be lean and gas-prone. Reservoir and seal facies tend to be better in deep marine (generally older) strata. Reservoir quality is generally poor due to breakdown of labile volcanic grains, but younger sandstones tend to be more quartz-rich.
The only significant prospective basin is the Larsen Basin, east of the Antarctic Peninsula. Geological evidence suggests that the best plays would involve deep strata. The major problem in this basin is the very difficult access, even by Antarctic standards.
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Antarctica as an Exploration Frontier—Hydrocarbon Potential, Geology, and Hazards
The 10 papers contained in this publication are oriented toward the hydrocarbon potential of Antarctica. Contents include regional seismic surveys involving tectonic and stratigraphic interpretations extending from the Adelie Coast margin, over the Ross Sea and Bellingshausen Sea, throughthe Bransfield Straight and along the northern Antarctic Peninsula. Mesozoic sedimentary basins are compared in detail, and a tectonic synthesis of Antarctica and the surrounding southern seas is presented.