Anadyr Basin: Geological Structure, Tectonic Evolution and Oil-and-Gas Potential
Mikhail Antipov1, Grigoriy Bondarenko1, and Eduard Shipilov2
1Geological Institute Russian Academy of Sciences, Moscow, Russia.
2Murmansk Marine and Biological Institute Russian Academy of Sciences, Murmansk, Russia.
An attempt to summarize knowledge on tectonic evolution, sedimentation conditions in Anadyr depression and published data on results of oil and gas exploration work within its range was made in this work. Findings were interpreted in the context of new geological and structural data obtained by the authors during field investigations on the territory of Chukotsky peninsula.
History of Anadyr basin sedimentary cover formation reflects tectonic history of the region which developed in the Late Mesozoic and Cenozoic at the turn of Southern-Anyuy oceanic basin, the Asian continental edge and multiage convergence zones along its boundaries with Pacific. There are three major stages of basin cover formation: 1) after Albian-Cenomanian orogeny in Late Cretaceous-Early Eocene under conditions of passive heterogeneous continental margin the lower part of cover was formed; 2) in the middle Eocene-Oligocene sedimentation proceeded along with stretching and rifting of the northern part of paleobasin and compression in its southern part, it was determined by northward migration of foredeep trough before the front of Koryak accretion orogen; 3) Miocene sedimentation activation is connected with continental riftogenesis.
The sediment complex of the first sedimentation stage concerns primarily southern part of Anadyr depression (Maynitsky and Lamutsky trough). Maximum thickness of a sedimentary complex of the second stage of sedimentation is fixed primarily in the southern part of the basin, and in Central and East-Anadyr trough. Accumulation of deposits of the third stage was mostly intense in the central and northern parts of Anadyr depression.
The analysis of geological and geophysical materials testifies that for the southern part of Anadyr basin thrust structure is typical. Amplitude of overlapping by thrusts within Maynitsky trough reaches tens kilometers. Vertical thickness of tectonically screened Palaeogene-Neogene deposits exceeds 10 km within the southern part of Maynitsky trough.
The most perspectives of new petroleum and gas fields detection are connected with the southern part of Anadyr depression. Detection of industrial (commercially productive) hydrocarbons in upper Cretaceous, Eocene and There are Upper Oligocene-Miocene collectors localized in structural-lithologic traps of under-thrust type.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia