Early Cambrian microfossils from the cherts in carbonates of the Kuruktag area, the Tarim block

Abstract

The basal Cambrian is characteristic for the appearance of small shelly fossils and acanthomorphic acritarchs with relatively small vesicles. In the Tarim Block (NW China) and South China, this microfossil assemblage is dominated by small acanthomorphs and was referred to as the 'Micrhystridium-Paracymatiosphaera-Megathrix' (MPM) association, based on microfossils from the early Cambrian Yurtus and Xishanblaq Formations of the Tarim Block. This study provides the new early Cambrian microfossil assemblage preserved in cherts of carbonates in Tikebuladahuang section of the Kruktag area, Tarim Block. These early Cambrian microfossil assemblages come from early Cambrian Upper Xishanblaq Formation in Tikebuladahuang section correlated with the Cambrian Stage 2, and the microfossil association is dominated by Heliosphaeridium irregulare n. sp., sponge spicules, Leiosphaeridia spp., and Siphonophycus sp. also occur.

Cryogenian and Ediacaran integrative stratigraphy, biotas, and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

“…This inference is further supported by the carbon isotope chemostratigraphic correlation, indicating a depositional age younger than 570 Ma for the Hanchalchough Formation (Wang et al, 2023). On the other hand, the earliest record of the Cambrian microfossils is found in the Xishanblaq Formation (Yao et al, 2005;Zhang Z et al, 2023), which sits above the Hanchalchough Formation. Based on the evidence provided above, the tillites in the Hanchalchough Formation could be attributed to a late Ediacaran glaciation.…”