Paleoenvironmental evolution of the Eastern Paratethys: Tracing the Tethys Ocean legacy through geochemical proxies

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology Pub Date : 2025-07-18 DOI:10.1016/j.chemgeo.2025.122974

Dan V. Palcu Rolier , Zhanhong Liu , Wei Wei , Sergey Popov , Larisa Golovina , Iuliana Vasiliev , Wout Krijgsman , Thomas Algeo

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引用次数: 0

Abstract

During the Oligocene to Miocene, the Paratethys Sea emerged as the northern offshoot of the Tethys Ocean, separated from the Mediterranean by the Alpine-Himalayan mountain range. Its history was characterized by the opening, restriction and closure of marine gateways, resulting in significant paleoenvironmental changes, including episodes of anoxia and extreme salinity fluctuations. This study investigates the paleoenvironmental evolution of the Paratethys Sea by focusing on variations in salinity and paleoventilation through advanced geochemical analyses of key sections (Belaya, Panagia, Zhelezhny Rog) in the northern Caucasus and Taman Peninsula of Russia, spanning 42 to 4 Ma. We apply a suite of geochemical proxies to reconstruct paleosalinity [e.g., using the boron/gallium (B/Ga), strontium/barium (Sr/Ba), sulfur/total organic carbon (S/TOC) ratios] and paleoredox conditions [e.g., using the organic carbon/phosphorus (C_org/P) ratio as well as trace-metal enrichment factors such as Zn_EF, V_EF, and Mo_EF]. Our results indicate that Paratethys was influenced by both global and local events, with regional factors becoming increasingly significant as isolation and fragmentation progressed. Paleoventilation proxies reveal two main episodes of anoxia: the Kuma Anoxic Event, a regional event exhibiting oceanic anoxic signatures that encompassed the time of the Middle Eocene Climatic Optimum (MECO) and; the Maikop Persistent Basin Water Stratification (PBWS) event, coinciding with the Eocene-Oligocene Transition (EOT) and lasting until the Middle Miocene Climatic Optimum (MMCO), reflecting characteristics of an enclosed sea; and a weaker, less stable suboxic-anoxic episode in the late Miocene, associated with Megalake Paratethys. Paleosalinity proxies depict both transitions from marine to brackish conditions, such as the late Maikop salinity decrease and significant short-lived marine episodes, such as the MMCO-related mid-Langhian flood (14.8 Ma), the Badenian-Sarmatian Extinction Event (12.65 Ma) and the Intra-Maeotian Event (6.8 Ma). These findings emphasize the critical role of marine connectivity as a trigger of salinity and ventilation changes in the Eastern Paratethys's evolution, laying the groundwork for future studies on restricted basins.

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东特提斯古环境演化：利用地球化学指标追踪特提斯海洋遗产

在渐新世到中新世期间，帕拉提提斯海作为特提斯洋的北部分支出现，被阿尔卑斯-喜马拉雅山脉与地中海隔开。其历史以海洋门户的开启、限制和关闭为特征，导致了重大的古环境变化，包括缺氧和极端盐度波动。本研究通过对北高加索和俄罗斯塔曼半岛42 ~ 4 Ma的关键剖面（Belaya、Panagia、Zhelezhny Rog）进行先进的地球化学分析，以盐度和古呼吸变化为重点，探讨了Paratethys海的古环境演化。我们使用了一套地球化学指标来重建古盐度[例如，使用硼/镓（B/Ga），锶/钡（Sr/Ba），硫/总有机碳（S/TOC）比率]和古氧化还原条件[例如，使用有机碳/磷（Corg/P）比率以及微量金属富集因子（如ZnEF， VEF和MoEF）]。研究结果表明，Paratethys同时受到全球和局部事件的影响，随着隔离和碎片化的进展，区域因素变得越来越重要。古通气指标揭示了两个主要的缺氧事件：熊马缺氧事件，这是一个区域性事件，显示了中始新世气候最佳（MECO）时期的海洋缺氧特征；迈科普持续性盆地水分层（PBWS）事件，与始新世—渐新世过渡（EOT）相吻合，持续到中新世中期气候最适期（MMCO），反映了一个封闭海的特征；而在中新世晚期则出现了一个较弱的、不太稳定的缺氧期，与巨湖Paratethys有关。古盐度代用物描述了从海相到微咸环境的转变，如迈可普晚期盐度降低，以及显著的短期海相事件，如与mmcco相关的朗县中期洪水（14.8 Ma）、巴登尼亚-萨尔马提亚灭绝事件（12.65 Ma）和马奥天内事件（6.8 Ma）。这些发现强调了海洋连通性在东帕拉提斯演化过程中作为盐度和通风变化触发因素的关键作用，为未来对限制性盆地的研究奠定了基础。

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来源期刊

Chemical Geology 地学-地球化学与地球物理

CiteScore

7.20

自引率

10.30%

发文量

374

审稿时长

3.6 months

期刊介绍： Chemical Geology is an international journal that publishes original research papers on isotopic and elemental geochemistry, geochronology and cosmochemistry. The Journal focuses on chemical processes in igneous, metamorphic, and sedimentary petrology, low- and high-temperature aqueous solutions, biogeochemistry, the environment and cosmochemistry. Papers that are field, experimentally, or computationally based are appropriate if they are of broad international interest. The Journal generally does not publish papers that are primarily of regional or local interest, or which are primarily focused on remediation and applied geochemistry. The Journal also welcomes innovative papers dealing with significant analytical advances that are of wide interest in the community and extend significantly beyond the scope of what would be included in the methods section of a standard research paper.