Paleoredox and lithofacies assessments in Deepwater intervals of the Monterey Formation, Santa Maria Basin, California: Insights from organic sulfur geochemistry

IF 5.6 2区 工程技术 Q2 ENERGY & FUELS
{"title":"Paleoredox and lithofacies assessments in Deepwater intervals of the Monterey Formation, Santa Maria Basin, California: Insights from organic sulfur geochemistry","authors":"","doi":"10.1016/j.coal.2024.104606","DOIUrl":null,"url":null,"abstract":"<div><p>Although the Monterey Formation has been studied extensively for its petroleum system and Miocene climate insights, debates persist regarding its paleo-redox conditions. Furthermore, its characteristic lithofacies offer a natural laboratory for developing tools to differentiate siliceous and calcareous rocks in deepwater environments. This study evaluated the potential of the Sulfur Index (SI = mg S<sub>org</sub>/g TOC), measured by Rock-Eval 7S, as a proxy for assessing paleoredox conditions by comparing the SI with iron speciation data. Additionally, high-resolution molecular analyses were performed to investigate possible relationships between sulfur compounds and rocks with different carbonate content. The findings indicate higher SI values and higher concentrations of benzothiophenes over dibenzothiophenes in the siliceous lithofacies compared to the calcareous lithofacies. This suggests that the mineral matrix plays a crucial role in influencing the process by which sulfur-rich kerogen undergoes cracking when placed under thermal stress. The SI may support a paleoredox interpretation for the Monterey Formation, differing from previous interpretations based only on iron speciation. This alternative interpretation involves a more extensive water-column euxinia, distinct from the seasonal euxinia suggested in previous work. This study represents a practical and pioneering workflow based on sulfur data derived from Rock-Eval 7S for paleoredox and lithofacies assessments, opening avenues for further research.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6000,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Coal Geology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0166516224001630","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0

Abstract

Although the Monterey Formation has been studied extensively for its petroleum system and Miocene climate insights, debates persist regarding its paleo-redox conditions. Furthermore, its characteristic lithofacies offer a natural laboratory for developing tools to differentiate siliceous and calcareous rocks in deepwater environments. This study evaluated the potential of the Sulfur Index (SI = mg Sorg/g TOC), measured by Rock-Eval 7S, as a proxy for assessing paleoredox conditions by comparing the SI with iron speciation data. Additionally, high-resolution molecular analyses were performed to investigate possible relationships between sulfur compounds and rocks with different carbonate content. The findings indicate higher SI values and higher concentrations of benzothiophenes over dibenzothiophenes in the siliceous lithofacies compared to the calcareous lithofacies. This suggests that the mineral matrix plays a crucial role in influencing the process by which sulfur-rich kerogen undergoes cracking when placed under thermal stress. The SI may support a paleoredox interpretation for the Monterey Formation, differing from previous interpretations based only on iron speciation. This alternative interpretation involves a more extensive water-column euxinia, distinct from the seasonal euxinia suggested in previous work. This study represents a practical and pioneering workflow based on sulfur data derived from Rock-Eval 7S for paleoredox and lithofacies assessments, opening avenues for further research.

加利福尼亚州圣玛丽亚盆地蒙特雷地层深水区段的古氧化还原和岩性评估:有机硫地球化学的启示
尽管人们对蒙特雷地层的石油系统和中新世气候进行了广泛研究,但关于其古氧化还原条件的争论依然存在。此外,其特征岩相为开发区分深水环境中硅质岩和钙质岩的工具提供了一个天然实验室。本研究通过比较硫指数(SI = mg Sorg/g TOC)与铁标本数据,评估了用 Rock-Eval 7S 测量的硫指数(SI = mg Sorg/g TOC)作为评估古氧化还原条件的替代物的潜力。此外,还进行了高分辨率分子分析,以研究硫化合物与不同碳酸盐含量的岩石之间可能存在的关系。研究结果表明,与钙质岩层相比,硅质岩层的 SI 值更高,苯并噻吩的浓度高于二苯并噻吩。这表明,矿物基质在影响富硫角质在热应力作用下发生裂解的过程中起着至关重要的作用。SI可能支持对蒙特雷地层进行古氧化还原解释,有别于以往仅根据铁的种类进行的解释。这种替代解释涉及到更广泛的水柱氧化作用,有别于之前研究中提出的季节性氧化作用。这项研究代表了一种基于 Rock-Eval 7S 得出的硫数据进行古氧化还原和岩性评估的实用和开创性的工作流程,为进一步的研究开辟了道路。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
International Journal of Coal Geology
International Journal of Coal Geology 工程技术-地球科学综合
CiteScore
11.00
自引率
14.30%
发文量
145
审稿时长
38 days
期刊介绍: The International Journal of Coal Geology deals with fundamental and applied aspects of the geology and petrology of coal, oil/gas source rocks and shale gas resources. The journal aims to advance the exploration, exploitation and utilization of these resources, and to stimulate environmental awareness as well as advancement of engineering for effective resource management.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信