JoVE - Journal of Visualized Experiments
JoVE Visualize
Contact Us

Depositional Model and Controlling Factors of High-Quality Shales of the Wufeng and Longmaxi Formations in Western Chongqing, Sichuan Basin, China

  • 0School of Geosciences, Yangtze University, Wuhan 430100, China.
Acs Omega +

|

April 15, 2024

|

April 15, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

High-quality shale deposition depends on organic matter enrichment, driven by ocean upwelling and oxygen minimum zones (OMZ). These factors, varying with water depth, are key to understanding shale formation and guiding shale gas exploration.

Area Of Science

  • Geochemistry
  • Sedimentology
  • Paleoceanography

Background

  • Organic matter enrichment is crucial for high-quality shale formation.
  • High productivity and anoxia are traditionally linked to organic enrichment.
  • The dynamic interplay between productivity and anoxia in shale formation remains understudied.

Purpose Of The Study

  • To investigate the combined effects of ocean productivity and anoxia on organic matter enrichment in shale.
  • To understand the spatio-temporal variability of high-quality shale development.
  • To propose depositional models for high-quality shale formation.

Main Methods

  • Analysis of black shales from the Wufeng and Longmaxi Formations in western Chongqing.
  • Correlation of shale quality with oceanic anoxia and productivity evolution related to water depth.
  • Development of depositional models based on observed relationships.

Main Results

  • High-quality shale distribution is strongly linked to the oxygen minimum zone (OMZ).
  • Intense ocean upwelling during the late Wufeng Formation led to high productivity and thick shale deposition.
  • Weakened upwelling and OMZ expansion in the early Longmaxi Formation resulted in widespread high-quality shales.

Conclusions

  • Ocean upwelling and OMZ dynamics are critical controls on high-quality shale formation.
  • Two depositional models highlight the spatial and temporal variability in shale development.
  • Findings provide guidance for shale gas exploration and development strategies.