Holocene and Anthropocene sea-level records from Indonesia

印度尼西亚全新世和人类世海平面记录

• 批准号: 423705513
• 负责人: Professorin Dr. Hildegard Westphal, since 10/2020
• 金额: --
• 依托单位: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/423705513?language=en
• 关键词: Holocene; Anthropocene; sea; level; records

Sea-level changes through the Holocene have been geographically variable. Large-scale mechanisms responsible for the observed variability comprise the interplay between eustatic melt-water contributions and isostatic adjustments of the solid Earth resulting from postglacial mass exchange between polar ice sheets and the oceans. These processes are further nuanced through oceanographic factors that act on shorter time scales and regionally constrained. During the early Holocene, sea level has been rising rapidly in equatorial ocean basins, reflecting a dominant eustatic contribution far from the ice sheets. In the middle Holocene, when melting of ice sheets slowed down, isostasy became the dominant control on sea-level changes in the tropics as subsiding peripheral forebulges in higher latitudes induced a redistribution of water masses away from the equator towards the poles. In the late Holocene / Anthropocene, tropical sea-level variability has been largely determined by dynamic oceanographic and steric factors. Knowledge of the spatial and temporal interplay between the dominant drivers of Holocene sea-level changes in the far field is essential to understand past ice sheet dynamics, constrain Earth parameters in glacial isostatic adjustment models and evaluate anthropogenic influences. This project contributes to the understanding of the dominant drivers of Holocene / Anthropocene sea-level changes in Indonesia, an archipelago that is highly vulnerable to future sea-level rise. We will determine the rate of early Holocene sea-level rise and the timing when sea level first reached its present position from reconstructions based on coral reef drill cores in the tectonically stable Spermonde Archipelago, Sulawesi. Results will be compared to an ensemble of glacial isostatic adjustment simulations in order to detect at which point in time isostatic contributions became the dominant driver of early Holocene sea-level rise. This project will furthermore validate existing mid-Holocene sea-level reconstructions for southwest Sulawesi, which are characterized by large inconsistencies, through a thorough field evaluation of the origins of the used sea-level indicators. In combination with the early Holocene reconstructions, these results will be used to put precise constraints on the regional Earth model parameters and to provide a reliable isostatic background signal to the ongoing anthropogenic and dynamic oceanographic contributions. Lastly, this project will provide the first high-resolution sea-level record for the late Holocene / Anthropocene in Southeast Asia, based on floating chronologies from slabbed microatolls reaching back in time to the 17th century. This unique record will be used to evaluate the steric contribution on sea-level variability in the Indo-Pacific Warm Pool during the Little Ice Age and the 20th century global warming.

全新世的海平面变化在地理上是可变的。大规模的机制，负责观察到的变化，包括海平面融化水的贡献和均衡的固体地球之间的相互作用，从冰后期的质量交换极地冰盖和海洋之间的调整。这些过程通过在较短时间尺度上起作用并受区域限制的海洋学因素而进一步微妙变化。在全新世早期，赤道洋盆的海平面一直在迅速上升，反映了远离冰盖的主要海平面升降的贡献。在全新世中期，当冰盖融化减缓时，等纬度线成为热带海平面变化的主要控制因素，因为高纬度地区外围前隆的下沉导致了水团从赤道向两极的重新分布。在晚全新世/人类世，热带海平面的变化在很大程度上是由海洋动力学和空间因素决定的。全新世海平面变化的主要驱动因素之间的空间和时间的相互作用的知识在远场是必不可少的了解过去的冰盖动态，约束地球参数在冰川均衡调整模型和评估人为影响。该项目有助于了解印度尼西亚全新世/人类世海平面变化的主要驱动因素，印度尼西亚是一个极易受到未来海平面上升影响的群岛。我们将确定早全新世海平面上升的速度和时间时，海平面第一次达到目前的位置，从重建的基础上，在构造稳定的斯佩蒙德群岛，苏拉威西岛的珊瑚礁钻孔岩心。结果将进行比较，以检测在哪个时间点均衡的贡献成为全新世早期海平面上升的主要驱动力的冰川均衡调整模拟合奏。该项目还将通过对所使用的海平面指标的来源进行彻底的实地评价，验证苏拉威西西南部现有的中全新世海平面重建，其特点是存在很大的不一致性。结合早期全新世重建，这些结果将被用来把区域地球模型参数的精确约束，并提供一个可靠的均衡背景信号，正在进行的人为和动力海洋学的贡献。最后，该项目将根据可追溯到世纪的片状微环礁的浮动年表，提供东南亚晚全新世/人类世的第一个高分辨率海平面记录。这一独特的记录将用于评估小冰期和世纪全球变暖期间印度洋-太平洋暖池海平面变化的空间贡献。