English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Lake-phase organic-rich shales are widely developed in the fifth member (Xu5 Member) of the Triassic Xujiahe Formation in the Sichuan Basin. However, due to the lack of understanding of the paleoclimate and paleoenvironment, the mechanism of organic matter enrichment in the Xu5 Member shale is controversial. To address these issues, this study takes the X5 Member in the Tianfu area as a case study. By analyzing its paleoenvironmental characteristics and correlating with organic matter development, we elucidate the influence of paleoenvironmental conditions on organic matter enrichment patterns in X5 shale. The results show that: (1) the shale of the Xu5 Member has high total organic carbon content and the organic matter type is dominated by type III, which has good potential for anger. (2) Chemical index of alteration (CIA)–weathering index of Parker (WIP) cross-plots indicate first-cycle deposition of the Xu5 Member shales with significant terrigenous input. La/Th, Hf, and Al 2 O 3 /TiO 2  ratios collectively suggest relatively slow sedimentation rates. Provenance analysis reveals dominant felsic igneous sources with minor mafic contributions.  C -values and Sr/Cu ratios consistently indicate semi-humid to humid paleoclimatic conditions during deposition. Sr/Ba (&lt;0.5) and Al 2 O 3 /MgO (&gt;7) ratios constrain paleosalinity to freshwater-brackish conditions. Redox proxies (Ni/Co, U/Th, V/Cr, U EF , Mo EF ) uniformly demonstrate oxygenated bottom-water conditions. Productivity indicators (P/Ti, Cu/Ti, Ba bio ) reveal elevated paleoproductivity in early Xu5 3  to Xu5 2 , with lower values in overlying intervals. (3) The organic matter enrichment of the shale in the Xu5 Member is mainly affected by the redox conditions of the bottom water, paleoproductivity, and paleosalinity, and the more reducing the bottom water is, the higher the paleoproductivity and the higher the paleosalinity are, the more favorable the organic matter enrichment is. In addition, in the sub-member of Xu5 1  and Xu5 2 , paleoclimate, land-source input, and sedimentation rate are also secondary factors affecting the degree of organic matter enrichment.

open geosciences

Paleoenvironmental characteristics of continental shale and its significance to organic matter enrichment: Taking the fifth member of Xujiahe Formation in Tianfu area of Sichuan Basin as an example