PHANNEROZOIC EAST EUROPE- SIBERIA INTERACTION and PETROLEUM HABITAT of NORTHERN EURASIA

The principal tectonic elements in Northern Eurasia are East European and Siberian cratons. A smaller continental block, the Neoproterozoic Brentsia plate, is situated in the Arctic shelf. The cratons are surrounded by Neoproterozoic-Paleozoic orogens (Sobornov, K and Yakubchuk, A, 2004, Yakubchuk, A.S., 2004). Basement of the prolific West Siberian basin includes amalgamated folded Paleozoic terrains. The Paleozoic orogenic collage is sinistrally offset along the Transeurasian strike-slip fault, which was active during late Paleozoic-Triassic times. This fault extends from South Siberia towards Pai-Khoy and Novaya Zemlya displacing all pre-Mesozoic structures for as much as 1,000 km (Fig. 1). Figure 1. Structural scheme of Northern Eurasia and location of the major sedimentary basins. Dotted line is the Transeurasian fault. 133 Two major phases of sedimentary basin development in Northern Eurasia are recognized in the plate tectonic context. The first one started in the Late Precambrian and finished in the Late Permian (circa 750-250 Ma). Much of the preserved sedimentary deposits of these times are in the Lena-Tunguska, Timan-Pechora and Volga-Ural basins. They developed as asymmetrical foreland-type basin

SQUEEZED DIAPIRS OF THE TIMAN PECHORA BASIN: STRUCTURE, EVOLUTION AND PETROLEUM PROSPECTIVITY

Reprocessing and integrated interpretation of vintage and newly available data provided new insight into structural framework of thrust belt in the northeastern part of the Timan Pechora basin. It showed that structural evolution of the fold and thrust belt was influenced by the multiphase development of salt diapirs which finally were squeezed during pulses of the orogenic shortening. This was accompanied with expulsion of salt and the development of divergent thrusting. The improved seismic imaging has allowed for more accurate definition of the structure and stratigraphy below thrust sheets including salt sole in frontal zone of the fold and thrust belt. The updated interpretation shows new exiting opportunities for petroleum exploration provided by subsalt traps. © EAGE Conference and Exhibition 2021.All right reserved

Sedimentary response to a collision orogeny recorded in detrital zircon provenance of Greater Caucasus foreland basin sediments

The Greater Caucasus orogen on the southern margin of Eurasia is hypothesized to be a young collisional system and may present an opportunity to probe the structural, sedimentary and geodynamic effects of continental collision. We present detrital zircon U‐Pb age data from the Caucasus region that constrain changes in sediment routing and source exposure during the late Cenozoic convergence and collision between the Greater Caucasus orogen and the Lesser Caucasus, an arc terrane on the lower plate of the system. During Oligocene to Middle Miocene time, following the initiation of deformation within the Greater Caucasus, marine sandstones and shales were deposited between the Greater and Lesser Caucasus, and detrital zircon age data suggest no mixing of Greater Caucasus and Lesser Caucasus detritus. During Middle to Late Miocene time, Greater Caucasus detritus was deposited onto the Lesser Caucasus basin margin, and terrestrial, largely conglomeratic, sedimentation began between the Greater and Lesser Caucasus. Around 5.3 Ma, upper plate exhumation rates increased and shortening migrated to pro‐ and retro‐wedge fold‐thrust belts, coinciding with the initiation of foreland basin erosion. Sediment composition, provenance and structural data from the orogen together suggest the existence of a wide (230–280 km) marine basin that was progressively closed during Oligocene to Late Miocene time, probably by subduction/lithospheric underthrusting beneath the Greater Caucasus, followed by initiation of collision between the Lesser Caucasus arc terrane and the Greater Caucasus in Late Miocene to Pliocene time. The pace of the transition from hypothesized subduction to collision in the Caucasus is consistent with predictions from numerical modeling for a system with moderate convergence rates (<13 mm/yr) and hot lower plate continental lithosphere. Basement crystallization histories implied by our detrital zircon age data suggest the presence of two pre‐Jurassic sutures between stable Eurasia and the Lesser Caucasus, which likely guided later deformation.The Greater Caucasus may constitute a natural example of early continental collision. New detrital zircon U‐Pb geochronology data, together with published Cenozoic stratigraphy and structural data from the Greater Caucasus, suggests collision began in the Late Miocene to Pliocene, leading to diachronous changes in deformation and sedimentation in the orogen and associated basins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167026/1/bre12499.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167026/2/bre12499-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167026/3/bre12499-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167026/4/bre12499-sup-0003-FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167026/5/bre12499_am.pd

Oligocene uplift of the Western Greater Caucasus: an effect of initial Arabia–Eurasia collision

The Greater Caucasus is Europe's largest mountain belt. Significant uncertainties remain over the evolution of the range, largely due to a lack of primary field data. This work demonstrates that depositional systems within the Oligocene–Early Miocene Maykop Series on either side of the Western Greater Caucasus (WGC) display a similar provenance and divergent palaeocurrents away from the range, constraining a minimum age for the subaerial uplift of the range as early Early Oligocene. An Eocene–Oligocene hiatus, basal Oligocene olistostromes and a marked increase in nannofossil reworking also point to initial deformation in the earliest Oligocene. The initial uplift of the WGC occurred during the final assembly of the Tethysides to its south. Uplift commenced after the Late Eocene final suturing of northern Neotethys and during the initial collision of Arabia with the southern accreted margin of Eurasia. This suggests that compressional deformation was rapidly transferred across the collision zone from the indenting Arabian plate to its northern margin.<br/