Lower–Middle Jurassic facies patterns in the NW Afghan–Tajik Basin of southern Uzbekistan and their geodynamic context

Abstract

Based on eleven sections, the palaeoenvironments and depositional history of the northwestern Afghan-Tajik Basin in southern Uzbekistan have been reconstructed for the time interval Early Jurassic to Early Callovian. The earliest sediments, resting on Palaeozoic basement rocks, date from the Early Jurassic Period. Up to the end of the Early Bajocian time up to more than 500 m of non-marine sediments accumulated due to extensional tectonics inducing active subsidence. In the Late Bajocian time interval, transgression led to the establishment of siliciclastic ramps that were influenced by storm processes. After a condensed unit in the Middle Bathonian, sedimentation resumed in an outer carbonate ramp basinal setting as the subsidence rate outpaced the diminished siliciclastic sediment supply. The change from siliciclastic to carbonate sedimentation in the Middle Jurassic Period is thought to be multifactorial, reflecting levelling of relief in the hinterland, the subsidence moving to a thermally more quiet stage, and a change from humid to arid climatic conditions. These features are also observed in the area of present-day Iran. Similarly, the timing of the transgression coincides with that in eastern and northern Iran stressing the regional significance of this event. After the collisions of the Cimmerian terranes with Eurasia in the Late Triassic (e.g., Stampfli

Tajik Basin and Southwestern Tian Shan, Northwestern India‐Asia Collision Zone: 2. Timing of Basin Inversion, Tian Shan Mountain Building, and Relation to Pamir‐Plateau Advance and Deep India‐Asia Indentation

“…The Jurassic‐Cretaceous cooling recorded in the western Tian Shan likely is the vestige of widespread crustal extension after the “Eo‐Cimmerian” (Norian‐Rhaetian) orogeny, best documented in Uzbekistan and Iran. Extension almost ceased at the end of the Middle Jurassic (~160 Ma), with only minor normal faulting recorded in Upper Jurassic and Cretaceous strata; this time was mostly characterized by thermal subsidence (e.g., Brunet et al, 2017; Fürsich et al, 2015; Mordvintsev et al, 2017). For the often cited trigger of the cooling by collisions at the southern margin of Asia (e.g., De Grave et al, 2012, 2013; Glorie et al, 2011; Jepson, Glorie, Konopelko, Gillespie, et al, 2018), we see no structural evidence in the studied areas.…”

Facies analyses and depositional setting of the Lower Cretaceous Shurijeh–Shatlyk formations in the Kopeh Dagh–Amu Darya Basin (Iran and Turkmenistan)

“…Although there are limited studies on the sedimentological characteristics of the Shurijeh-Shatlyk formations, particularly in the eastern part of the basin (Turkmenistan, Uzbekistan, and Afghanistan), recent studies on the Kopeh Dagh Foldbelt have indicated that the Shurijeh-Shatlyk formations were deposited in arid to semiarid climatic conditions in palaeolatitudes of about 30°to 40°N (Fursich, Brunet, Auxie'tre, & Munsch, 2015;Mortazavi, Moussavi-Harami, Brenner, & Mahboubi, 2013;Moussavi-Harami, Mahboubi, Nadjafi, Brenner, & Mortazavi, 2009;Thomas, Cobbold, Shein, & Le Douaran, 1999). In addition, Moussavi-Harami and Brenner (1990) suggested that the siliciclastic sediments of the Shurijeh Formation have metamorphic, igneous and sedimentary sources that derived from south and south-west of Mashhad (i.e., north-east Iran).…”

Geological evolution of Central Asian Basins and the western Tien Shan Range

“…Stampfli & Borel 2002;Barrier & Vrielynck 2008, 2017Wilmsen et al 2009;Zanchi et al 2009Zanchi et al , 2012, a number of new or rejuvenated sedimentary basins formed north of the main collision zone in Central Asia, including the Amu Darya Basin (extending mainly across Turkmenistan and Uzbekistan) and the Afghan-Tajik Basin (extending across Uzbekistan, Tajikistan and Afghanistan) (e.g. Thomas et al 1999a;Melikhov 2000Melikhov , 2013Melikhov , 2017Brookfield & Hashmat 2001;Ulmishek 2004;Klett et al 2006;Fü rsich et al 2015;Brunet et al 2017). The evolution of these two basins was closely linked from the Late Palaeozoic onwards; indeed, during Jurassic times the two basins were connected.…”

“…The Jurassic -Cretaceous was characterized by a general planation of the previously formed relief (e.g. Makarov 1977;Chediya 1986;Burbank et al 1999;Allen et al 2001;Cunningham et al 2003;Jolivet et al 2010Jolivet et al , 2013Jolivet et al , 2015, providing sediments to these newly forming extensional basins (Brookfield & Hashmat 2001;Klett et al 2006;Fü rsich et al 2015;Brunet et al 2017).…”

“…In Central Asia, the Mesozoic period was marked by pronounced tectonic activity but also by climatic changes, specifically, the transition from a humid climate during the Middle TriassicMiddle Jurassic to a semi-arid-arid climate through to the Late Jurassic -Early Cretaceous (e.g. Hendrix et al 1992;Shao et al 2003;Cecca et al 2005;Fü rsich et al 2015;Jolivet 2015;Jolivet et al 2015;McCann 2016a, b;Schnyder et al 2016;Brunet et al 2017). Subsequently, during the early Cenozoic regionally well-correlated marine transgressions occurred (Bosboom 2013;Bosboom et al 2015).…”