Eustatic and tectonic controls on mixed carbonate-siliciclastic ramp deposits in the South Pyrenean foreland basin: The Eocene Alveolina Limestone

IF 2 3区 地球科学 Q1 GEOLOGY
Stefan Schröder, Oliver Neame, Amber Finch, Miquel Poyatos-Moré
{"title":"Eustatic and tectonic controls on mixed carbonate-siliciclastic ramp deposits in the South Pyrenean foreland basin: The Eocene Alveolina Limestone","authors":"Stefan Schröder,&nbsp;Oliver Neame,&nbsp;Amber Finch,&nbsp;Miquel Poyatos-Moré","doi":"10.1002/dep2.70025","DOIUrl":null,"url":null,"abstract":"<p>Palaeogene depositional systems in the South Pyrenean foreland were influenced by eustatic sea level changes, compressive and salt tectonics, as well as biotic and environmental changes during and after the Palaeocene–Eocene Thermal Maximum (PETM). Decoupling these factors requires careful sedimentary and stratigraphic analysis. This study combines outcrop observations and microfacies analysis to derive a depositional model and to evaluate the relative roles of eustasy, tectonics and skeletal biota during deposition of the lower Eocene Alveolina Limestone, which immediately post-dates the PETM. The studied succession is preserved in the footwall of the Montsec thrust. Diagnostic skeletal grains show a systematic upward change from coastal (miliolid foraminifera, charophytes) and inner ramp (miliolid and alveolinid foraminifera), through tidal bars or dunes (alveolinid and nummulitid foraminifera), to middle ramp (bryozoans, echinoderms, encrusters—mainly acervulinid foraminifera and coralline red algae) environments, a deepening succession recording the global early Eocene transgression. A condensation interval rich in red algae, iron and glauconite grains and cement marks the maximum flooding and passage to the overlying tidally-influenced Baronia Formation sandstones. The fossil assemblage is consistent with expansion of foraminifera at the expense of corals in the aftermath of the PETM. Lower accommodation space and higher detrital input in the footwall of the Montsec thrust caused stratigraphic thinning and interbedding of carbonate debrites and sandstones. This suggests that the Montsec tectonic structure was at least partially emergent already during the earliest Eocene. Uplift of the Montsec tectonic structure, which was probably related to salt movements and compressive tectonics, and the early Eocene transgression facilitated a detrital provenance shift from a southern provenance in the Palaeocene to north/northeasterly Pyrenean sources. The large tidal bedforms in the Alveolina Limestone, deposited by currents amplified in a narrow strait, may provide evidence for the development of an Atlantic-Mediterranean seaway.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 4","pages":"1132-1165"},"PeriodicalIF":2.0000,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70025","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Depositional Record","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/dep2.70025","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0

Abstract

Palaeogene depositional systems in the South Pyrenean foreland were influenced by eustatic sea level changes, compressive and salt tectonics, as well as biotic and environmental changes during and after the Palaeocene–Eocene Thermal Maximum (PETM). Decoupling these factors requires careful sedimentary and stratigraphic analysis. This study combines outcrop observations and microfacies analysis to derive a depositional model and to evaluate the relative roles of eustasy, tectonics and skeletal biota during deposition of the lower Eocene Alveolina Limestone, which immediately post-dates the PETM. The studied succession is preserved in the footwall of the Montsec thrust. Diagnostic skeletal grains show a systematic upward change from coastal (miliolid foraminifera, charophytes) and inner ramp (miliolid and alveolinid foraminifera), through tidal bars or dunes (alveolinid and nummulitid foraminifera), to middle ramp (bryozoans, echinoderms, encrusters—mainly acervulinid foraminifera and coralline red algae) environments, a deepening succession recording the global early Eocene transgression. A condensation interval rich in red algae, iron and glauconite grains and cement marks the maximum flooding and passage to the overlying tidally-influenced Baronia Formation sandstones. The fossil assemblage is consistent with expansion of foraminifera at the expense of corals in the aftermath of the PETM. Lower accommodation space and higher detrital input in the footwall of the Montsec thrust caused stratigraphic thinning and interbedding of carbonate debrites and sandstones. This suggests that the Montsec tectonic structure was at least partially emergent already during the earliest Eocene. Uplift of the Montsec tectonic structure, which was probably related to salt movements and compressive tectonics, and the early Eocene transgression facilitated a detrital provenance shift from a southern provenance in the Palaeocene to north/northeasterly Pyrenean sources. The large tidal bedforms in the Alveolina Limestone, deposited by currents amplified in a narrow strait, may provide evidence for the development of an Atlantic-Mediterranean seaway.

Abstract Image

南比利牛斯前陆盆地碳酸盐-硅质混合斜坡沉积的隆起和构造控制:始新世肺泡灰岩
古新世—始新世热极大期(PETM)前后,南比利牛斯前陆古近系沉积体系受到海平面上升、挤压构造和盐构造以及生物和环境变化的影响。将这些因素分离需要仔细的沉积和地层分析。本研究结合露头观测和微相分析,建立了沉积模型,并评价了始新世下肺泡灰岩沉积过程中游鼓、构造和骨骼生物群的相对作用。所研究的演替被保存在蒙特塞克逆冲构造的下盘。诊断型骨骼颗粒显示出从海岸(千孔虫、轮虫)到内斜坡(千孔虫和肺泡孔虫),经过潮坝或沙丘(肺泡孔虫和多孔孔虫)到中斜坡(苔藓虫、棘皮动物、以针孔虫和珊瑚红藻为主的壳类)环境的系统向上变化,记录了全球始新世早期海侵的不断深化的演替过程。一个富含红藻、铁、海绿石颗粒和胶结物的凝结层段标志着上覆受潮汐影响的巴罗尼亚组砂岩的最大洪水和通道。化石组合与新第三纪新第三纪后有孔虫以牺牲珊瑚为代价的扩张相一致。蒙塞克逆冲下盘可容纳空间减小,碎屑输入增大,导致地层变薄,碳酸盐岩碎屑与砂岩互层。这表明,在始新世早期,蒙特塞克构造至少部分已经出现。蒙塞克构造的抬升(可能与盐运动和挤压构造有关)和始新世早期的海侵使碎屑物源从古新世的南部物源向比利牛斯山脉的北部/东北部物源转移。阿尔韦利纳石灰岩中的大型潮汐床是由狭窄海峡中放大的水流沉积的,可能为大西洋-地中海海道的发展提供证据。
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
CiteScore
4.10
自引率
16.70%
发文量
42
审稿时长
16 weeks
×
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:604180095
Book学术官方微信