OH-isoGDGTs as a paleothermometer for bottom seawater temperature in the eastern China marginal seas

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology Pub Date : 2025-04-01 DOI:10.1016/j.chemgeo.2025.122768

Yuning Wang , Huamao Yuan , Jinming Song , Junhui Chen , Fengmin Pan , Qidong Wang , Xuegang Li , Liqin Duan , Ning Li , Yueqi Wang

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引用次数: 0

Abstract

Hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH-isoGDGTs), which exhibit similar behavior to regular isoprenoid GDGTs (isoGDGTs), have shown potential for reconstructing past seawater temperature than isoGDGTs in marginal seas due to their reduced impact from terrestrial inputs. However, there are marginal seas exhibit regional variability, such as water depth and seasonality bias, in terms of how isoGDGTs and OH-isoGDGTs reflect the marine environment. In this study, we investigated OH-isoGDGTs in both suspended particulate matters and surface sediments of the eastern China marginal seas (ECMS), to constrain which water layer temperature the sedimentary OH-isoGDGTs-based indices better represents. Our results showed that OH-isoGDGTs concentrations were generally higher in bottom waters than in surface waters. Additionally, the composition of OH-isoGDGTs (and also isoGDGTs) in surface sediments showed no significant differences (p > 0.05) with that of bottom waters and significant differences (p < 0.05) with that of surface waters, indicating that OH-isoGDGTs in surface sediments were mainly derived from the deposition of bottom waters. Furthermore, OH-isoGDGTs-based indices in surface sediments correlated better with bottom seawater temperature (BST) than with surface seawater temperature (SST), reinforcing the notion that sedimentary OH-isoGDGTs mainly derive from bottom waters. Moreover, OH-isoGDGTs-based indices showed stronger correlations with summer and autumn temperatures compared to other seasons, and exhibited improved accuracy in BST reconstruction than isoGDGTs-based TEX₈₆ indices, suggesting that sedimentary OH-isoGDGTs-based indices are potential BST proxies for warm seasons in the ECMS. Our findings enhance the understanding of the potential of OH-isoGDGTs as paleothermometer proxies in marginal seas and offer insights into their application for more precise paleoceanographic reconstructions.

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OH-isoGDGTs作为中国东部边缘海底部海水温度的古温度计

羟基化类异戊二烯甘油二烷基甘油四醚（OH-isoGDGTs）表现出与常规类异戊二烯甘油四醚（isoGDGTs）相似的行为，由于受陆地输入的影响较小，在边缘海域，与类异戊二烯甘油四醚相比，具有重建过去海水温度的潜力。然而，在等ogdgt和oh -等ogdgt如何反映海洋环境方面，边缘海表现出区域变异性，如水深和季节性偏差。本文对中国东部边缘海（ECMS）表层沉积物和悬浮颗粒物中的OH-isoGDGTs进行了研究，以确定沉积OH-isoGDGTs指标更能代表哪一种水层温度。我们的研究结果表明，OH-isoGDGTs在底层水体中的浓度普遍高于地表水。此外，表层沉积物中OH-isoGDGTs（以及isoGDGTs）的组成没有显著差异(p >；0.05)，与底水差异显著(p <；0.05)，表明表层沉积物中的OH-isoGDGTs主要来源于底层水的沉积。此外，表层沉积物中基于OH-isoGDGTs的指数与底层海水温度（BST）的相关性优于与表层海水温度（SST）的相关性，强化了沉积OH-isoGDGTs主要来源于底层海水的观点。此外，与其他季节相比，基于oh - isogdgts的指数与夏季和秋季气温的相关性更强，并且在BST重建方面比基于isogdgts的TEX86指数具有更高的准确性，这表明基于oh - isogdgts的沉积指数是ECMS暖季BST的潜在替代指标。我们的研究结果增强了对oh - isogdgt作为边缘海古温标的潜力的理解，并为它们在更精确的古海洋学重建中的应用提供了见解。

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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.