First Identification of the Ediacaran Yukengou Formation in the Western Kuruktag Block, Northeastern Tarim, and Its Implications for Neoproterozoic Rift Basin Evolution

Abstract

The Cryogenian–Ediacaran strata in the Kuruktag block, northeastern Tarim Craton, are pivotal for deciphering the breakup of Neoproterozoic Rodinia and related peripheral subduction processes. This study reveals previously unidentified Ediacaran strata in the western Kuruktag block, characterized by deltaic plain clastic rocks and channel deposits. Zircon geochronological analyses of basalts and sandstones indicate a maximum depositional age of ~596 Ma, thereby attributing these strata to the Ediacaran Yukengou Formation in conjunction with prior paleontological findings. The prevalence of lithic fragments and two primary detrital zircon age populations within the Yukengou Formation sandstones suggest a rift basin environment, in contrast to a passive continental margin, receiving detrital material from the neighboring Paleoproterozoic basement and Neoproterozoic magmatic activity. As a result, the Cryogenian–Ediacaran strata are posited to have been deposited in an aulacogen basin. The presence of numerous Neoproterozoic zircon grains further implies significant volcanic events preceding and concurrent with Cryogenian rifting, suggesting that continental rifting along the northeastern Tarim margin may have been instigated by subduction-induced extension.