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

A rare glimpse into the Jurassic period (Bajocian–Bathonian) within the UNESCO-listed Western Tien Shan, specifically the Sarbatyr inlier of Uzbekistan's Kyzylkum region, reveals a dynamic interplay between terrestrial and marine environments. The study, focusing on the Kuduksarbatyr Formation, identifies six distinct sedimentary facies transitioning from conglomerates to mudstones, deposited in distal alluvial fan settings that interdigitated with nearshore/lagoonal sediments rich in fossil fragments and glauconite. This succession highlights three significant transgressive events, including two global Bajocian events and a notable Bajocian–Bathonian boundary event, suggesting prolonged marine influence—contrary to earlier interpretations that assumed a continental setting by the Bathonian. The research underscores the complex interplay between eustatic sea-level changes and local tectonic activity in shaping these ancient landscapes.

McCann, T. (2016). The Jurassic of the Western Tien Shan: the Central Kyzylkum Region, Uzbekistan. Geological Society, London, Special Publications, 427(1), 411–437. https://doi.org/10.1144/sp427.13