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GEOREF RECORD

Oblique to orthogonal convergence across the Turan Block in the post-Miocene

Nikos Lyberis and Geoff Manby
Oblique to orthogonal convergence across the Turan Block in the post-Miocene
AAPG Bulletin (July 1999) 83 (7): 1135-1160

Abstract

The 2-17-km-thick, post-Triassic sediments of the Turan continental block accumulated in a south-dipping basin characterized by fault-controlled facies and thickness variations. Since the late Miocene, the thickest part of the basin fill, on the southern margin of the Turan Block, has been folded and uplifted as the Kopet Dag Range, in response to the Iran-Turan convergence. The Apsheron sill, which separates the northern continental from the southern oceanic Caspian Sea basins, links the Kopet Dag-Greater Balkan ranges (Turkmenistan) to the Caucasus (Azerbaijan). The large-scale east-west- to west-northwest-east-southeast-oriented arrays of periclinal folds of the Kopet Dag Range, which indicate a north-south oriented compression, were generated by a fault propagation mechanism. The migration and accumulation of hydrocarbons has been controlled by the deformation pattern. The 75 km of north-south shortening in the western Kopet Dag-Greater Balkan area can be resolved into 70 km of pure compression, orthogonal to the N120 degrees -oriented Ashgabat Fault, and 35 km of dextral slip along this fault. The north-south Iran-Asia relative motion has produced the oblique convergent northwest-southeast structures along the dextral Ashgabat Fault and the pure convergent east-west structures in the western Kopet Dag-Greater Balkan region. The orientation of the structures has been controlled by the angular relationship between the relative motion of two blocks and the orientation of their boundaries. The Ashgabat Fault as a major crustal anisotropy has concentrated the deformation into a narrow fold and thrust belt, whereas in the west the deformation is distributed over a wider area. The pattern of deformation has been controlled by the Iran-Turan boundary conditions.


ISSN: 0149-1423
EISSN: 1558-9153
Coden: AABUD2
Serial Title: AAPG Bulletin
Serial Volume: 83
Serial Issue: 7
Title: Oblique to orthogonal convergence across the Turan Block in the post-Miocene
Affiliation: University of Paris VI, Department of Geotectonics, Paris, France
Pages: 1135-1160
Published: 199907
Text Language: English
Publisher: American Association of Petroleum Geologists, Tulsa, OK, United States
References: 41
Accession Number: 1999-060181
Categories: Structural geologyEconomic geology, geology of energy sources
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., sketch maps
N42°34'60" - N44°00'00", E22°15'00" - E28°00'00"
N36°00'00" - N48°00'00", E47°00'00" - E53°00'00"
N35°00'00" - N43°30'00", E54°00'00" - E66°00'00"
N35°00'00" - N39°30'00", E52°30'00" - E63°00'00"
Secondary Affiliation: University of Greenwich, School of Earth Sciences, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States
Update Code: 199920
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