TY - JOUR

T1 - The Itmurundy Accretionary Complex, Northern Balkhash Area

T2 - Geological Structure, Stratigraphy and Tectonic Origin

AU - Safonova, I. Yu

AU - Perfilova, A. A.

AU - Obut, O. T.

AU - Savinsky, I. A.

AU - Chyornyi, R. I.

AU - Petrenko, N. A.

AU - Gurova, A. V.

AU - Kotler, P. D.

AU - Khromykh, S. V.

AU - Krivonogov, S. K.

AU - Maruyama, Sh

PY - 2019/5/1

Y1 - 2019/5/1

N2 - Abstract: The Itmurundy zone of the northern Balkhash area is a Pacific-type orogenic belt. It possesses a complex geological structure and hosts rocks of mantle, accretionary and post-orogenic associations. The volcanic and sedimentary rocks of the accretionary association belong to three suites: Itmurundy (O1-2), Kazyk (O2-3) and Tyuretai (O3-S1). The suites are separated by tectonic unconformities or faults of three orders: 1) large regional faults; 2) medium faults separating mantle and oceanic accreted rocks; 3) small faults separating packages consisting of oceanic sediments. The Itmurundy Fm. (O1-2) is the most lithologically variable consisting of oceanic basalt, pelagic chert, hemipelagic siliceous mudstone and siltstone, and trench greywacke sandstone. The packages, each consisting of chert-siliceous mudstone, are separated from each other by 2nd and 3rd order faults of probably thrust nature, i.e. they are parts of duplex structures. The presence of duplex structures and the high degree of deformation of Itmurundy Fm. rocks are typical of accretionary complexes. The associations of volcanic and sedimentary rocks under study represent a full section of oceanic plate stratigraphy (OPS): basalt (MORB, OIB)—chert (pelagic)—siliceous mudstone, siltstone and shale (hemipelagic)—trench sandstones (greywacke). The structural position and the lithology of Itmurundy rocks accord well with the model of formation of accretionary complexes at Pacific-type convergent margins, in particular, those in the western Pacific.

AB - Abstract: The Itmurundy zone of the northern Balkhash area is a Pacific-type orogenic belt. It possesses a complex geological structure and hosts rocks of mantle, accretionary and post-orogenic associations. The volcanic and sedimentary rocks of the accretionary association belong to three suites: Itmurundy (O1-2), Kazyk (O2-3) and Tyuretai (O3-S1). The suites are separated by tectonic unconformities or faults of three orders: 1) large regional faults; 2) medium faults separating mantle and oceanic accreted rocks; 3) small faults separating packages consisting of oceanic sediments. The Itmurundy Fm. (O1-2) is the most lithologically variable consisting of oceanic basalt, pelagic chert, hemipelagic siliceous mudstone and siltstone, and trench greywacke sandstone. The packages, each consisting of chert-siliceous mudstone, are separated from each other by 2nd and 3rd order faults of probably thrust nature, i.e. they are parts of duplex structures. The presence of duplex structures and the high degree of deformation of Itmurundy Fm. rocks are typical of accretionary complexes. The associations of volcanic and sedimentary rocks under study represent a full section of oceanic plate stratigraphy (OPS): basalt (MORB, OIB)—chert (pelagic)—siliceous mudstone, siltstone and shale (hemipelagic)—trench sandstones (greywacke). The structural position and the lithology of Itmurundy rocks accord well with the model of formation of accretionary complexes at Pacific-type convergent margins, in particular, those in the western Pacific.

KW - accretionary complex

KW - basal

KW - Central Asian Orogenic Belt

KW - duplex

KW - ocean plate stratigraphy

KW - Pacific-type convergent margin

KW - sandstone

KW - siliceous sediments

KW - SIKHOTE-ALIN

KW - ROCKS

KW - ALIN OROGENIC BELT

KW - CRUST

KW - OCEAN PLATE STRATIGRAPHY

UR - http://www.scopus.com/inward/record.url?scp=85067400614&partnerID=8YFLogxK

U2 - 10.1134/S1819714019030072

DO - 10.1134/S1819714019030072

M3 - Article

AN - SCOPUS:85067400614

VL - 13

SP - 283

EP - 296

JO - Russian Journal of Pacific Geology

JF - Russian Journal of Pacific Geology

SN - 1819-7140

IS - 3

ER -