美国耶鲁大学Jennifer Kasbohm团队报道了中新世气候最佳期的高精度U-Pb年代学，及深海沉积物岩心年龄模型校正的新方法。该研究于2024年7月12日发表于《地质学》杂志。

据研究人员介绍，多年前回收的科学海洋钻探岩心(遗留岩心)，特别是旋转钻井回收的岩心，通常表现为不完全恢复和岩心扰动。

研究人员首次利用高精度的U-Pb锆石测年的新方法，对来自大洋钻探计划1000号地点（位于加勒比海的尼加拉瓜隆起）的火山灰进行测定，以确定中新世气候最佳期（MCO; ca.17-14Ma）。研究人员将测得的年龄放在一个新开发的框架中，以解决岩心不完全恢复问题，并将它们用于校准高分辨率块状碳酸盐岩δ¹³C和δ¹⁸O记录。

测定的1000号地点年龄显示，哥伦比亚河玄武岩群(CRBG)大火成岩省的火山活动与该地点最稳定的MCO温暖期相吻合。

然而，如果CRBG是MCO的主要驱动力，那么年代学可能会认为火山活动之前的除气作用是CO₂的主要来源。结果强调，本研究记录了一种很有前途的新方法，获得不依赖于与其他记录相关联的高分辨率、准确和精确的深海沉积物岩心数值年龄模型。

附：英文原文

Title: High-precision U-Pb geochronology for the Miocene Climate Optimum and a novel approach for calibrating age models in deep-sea sediment cores

Author: Jennifer Kasbohm, Blair Schoene, Ellen Thomas, Pincelli Hull

Issue&Volume: 2024-07-12

Abstract: Scientific ocean drilling cores recovered years ago (legacy cores), especially as recovered by rotary drilling, commonly show incomplete recovery and core disturbance. We present a novel method to date such cores by presenting the first high-precision U-Pb zircon ages targeting the duration of the Miocene Climate Optimum (MCO; ca. 1714 Ma) from volcanic ashes at Ocean Drilling Program Site 1000 (on the Nicaragua Rise in the Caribbean Sea). We place these ages within a newly developed framework to address incomplete core recovery and use them to calibrate a high-resolution bulk carbonate δ¹³C and δ¹⁸O record. Our Site 1000 ages show that volcanism of the Columbia River Basalt Group (CRBG) large igneous province was coincident with the interval of greatest sustained MCO warmth at this site. However, if the CRBG were the primary driver of the MCO, our chronology may allow for outgassing preceding volcanism as a major source of CO₂. We thus document a promising new way to obtain highly resolved, accurate, and precise numerical age models for legacy deep-sea sediment cores that does not depend on correlation to other records.

DOI: 10.1130/G52255.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52255.1/645502/High-precision-U-Pb-geochronology-for-the-MioceneredirectedFrom=fulltext