Abstract
Marine carbonate δ13C and δ18O values are commonly utilized as indicators of past climate and are thought to record primary seawater conditions. However, these minerals can be altered following deposition and burial, overprinting the primary signal to reflect subsurface conditions. Whereas the influence of post-depositional alteration is widely understood in carbonate-dominated sediments (Swart, 2015), the influence has not been as widely studied in mud-rich settings. This study analyzed the carbonate δ13C and δ18O values from carbonate intervals in the Late Pennsylvanian Wolfcamp D shale unit in the Midland Basin to evaluate the impact of post-depositional alteration on the interpretation of stable isotope compositions of carbonates in a mud-rich depositional environment. Here we show the importance of using multiple indicators to fully evaluate the impact of post-depositional alteration on the interpretation of the marine carbonate δ13C and δ18O values in mud-rich environments. The extent of diagenesis in the Wolfcamp D was primarily controlled by fluctuations in benthic redox chemistry, which controlled sulfate reduction and the preservation of organic matter. These processes influenced the extent of carbonate cementation in the bacterial sulfate reduction zone and during deep-burial, making the carbonates unreliable for intra-basinal correlations. The results of this study were incorporated into a conceptual model that can likely be applied as a framework for other studies in mud-rich depositional environments.
| Original language | English |
|---|---|
| Pages (from-to) | 196-212 |
| Number of pages | 17 |
| Journal | Chemical Geology |
| Volume | 524 |
| DOIs | |
| State | Published - Oct 5 2019 |
Bibliographical note
Funding Information:We would like to thank Pioneer Natural Resources for supplying the cores, additional data, and funding to AE, without which this project would not have been possible. We would like to thank Tom Spalding and the geoscience group from Pioneer Natural Resources for their contributions and feedback throughout the course of this project. We would also like to thank Dr. Jordon Munizzi, Rich Dabundo, James Thompson, and those in the KSIGL group who helped with laboratory work and the interpretation of the stable isotope data. The authors would also like to thank the editor Dr. Michael E. Böttcher and the two anonymous reviewers for their detailed comments which improved the manuscript significantly. Funding for the SEM and Electron-probe Micro Analyzer was provided by NSF grants 1551342 and 0824714 respectively, each to D. P. Moecher. Additional funding for research was provided by the Geological Society of America's Graduate Student Grant program and the American Association of Petroleum Geologists Grants-in-Aid Program.
Funding Information:
We would like to thank Pioneer Natural Resources for supplying the cores, additional data, and funding to AE, without which this project would not have been possible. We would like to thank Tom Spalding and the geoscience group from Pioneer Natural Resources for their contributions and feedback throughout the course of this project. We would also like to thank Dr. Jordon Munizzi, Rich Dabundo, James Thompson, and those in the KSIGL group who helped with laboratory work and the interpretation of the stable isotope data. The authors would also like to thank the editor Dr. Michael E. Böttcher and the two anonymous reviewers for their detailed comments which improved the manuscript significantly. Funding for the SEM and Electron-probe Micro Analyzer was provided by NSF grants 1551342 and 0824714 respectively, each to D. P. Moecher. Additional funding for research was provided by the Geological Society of America 's Graduate Student Grant program and the American Association of Petroleum Geologists Grants-in-Aid Program.
Publisher Copyright:
© 2019
Keywords
- Carbonate diagenesis
- Dolomitization
- Midland Basin
- δC
- δO
ASJC Scopus subject areas
- Geology
- Geochemistry and Petrology
