The Jurassic of the Western Tien Shan: the Central Kyzylkum Region, Uzbekistan

Abstract

AbstractThe Sarbatyr inlier in the Kyzylkum area, Uzbekistan contains rare outcrops of Jurassic (Bajocian–Bathonian) rocks which form part of the Kuduksarbatyr Formation. Six facies are differentiated in the general succession, ranging from conglomerates to mudstones. The coarser sediments were deposited in a distal alluvial fan setting, which interdigitated with nearshore/lagoonal marine sediments rich in fossil fragments and glauconite. The overall succession provides evidence of varying sea-levels over time, with three distinct ‘transgressive’ events being noted. Two global transgressive events have been recognized in the Bajocian with another significant event at the Bajocian–Bathonian boundary. While it is possible that the events recognized within the Sarbatyr succession correspond to these global events, the effects of local tectonic activity must also be taken into account. The re-examination of the sediments of the Kuduksarbatyr Formation extends the marine influence on sedimentation through to the Bathonian (previous interpretations suggested that the area was continental).