在查卡耶梅莱乌（阿根廷内乌肯盆地）下侏罗统普林斯巴赫阶至托阿尔阶界线的新年代约束。

New age constraints on the Lower Jurassic Pliensbachian-Toarcian Boundary at Chacay Melehue (Neuquén Basin, Argentina).

机构信息

Department of Earth Sciences, Khalifa University of Science and Technology, PO Box 12333, Abu Dhabi, UAE.

Department of Geology, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.

出版信息

Sci Rep. 2022 Mar 23;12(1):4975. doi: 10.1038/s41598-022-07886-x.

DOI:10.1038/s41598-022-07886-x

PMID:35322043

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8942990/

Abstract

The Pliensbachian-Toarcian boundary interval is characterized by a ~ 3‰ negative carbon-isotope excursion (CIE) in organic and inorganic marine and terrestrial archives from sections in Europe, such as Peniche (Portugal) and Hawsker Bottoms, Yorkshire (UK). A new high-resolution organic-carbon isotope record, illustrating the same chemostratigraphic feature, is presented from the Southern Hemisphere Arroyo Chacay Melehue section, Chos Malal, Argentina, corroborating the global significance of this disturbance to the carbon cycle. The negative carbon-isotope excursion, mercury and organic-matter enrichment are accompanied by high-resolution ammonite and nannofossil biostratigraphy together with U-Pb CA-ID-TIMS geochronology derived from intercalated volcanic ash beds. A new age of ~ 183.73 + 0.35/- 0.50 Ma for the Pliensbachian-Toarcian boundary, and 182.77 + 0.11/- 0.15 for the tenuicostatum-serpentinum zonal boundary, is assigned based on high-precision U-Pb zircon geochronology and a Bayesian Markov chain Monte Carlo (MCMC) stratigraphic age model.

摘要

Pliensbachian-Toarcian 边界间隔的特点是有机和无机海洋和陆地档案中的3‰负碳同位素偏移（CIE），来自欧洲的剖面，如葡萄牙的 Peniche 和英国的 Yorkshire 的 Hawsker Bottoms。来自阿根廷 Chos Malal 的 Arroyo Chacay Melehue 剖面的新的高分辨率有机碳同位素记录说明了相同的化学地层特征，证实了这种对碳循环的干扰对全球的重要意义。负碳同位素偏移、汞和有机质富集伴随着高分辨率菊石和钙质超微化石生物地层学，以及来自夹层火山灰床的 U-Pb CA-ID-TIMS 地质年代学。基于高精度 U-Pb 锆石地质年代学和贝叶斯马尔可夫链蒙特卡罗（MCMC）地层年龄模型，为 Pliensbachian-Toarcian 边界分配了183.73±0.35/-0.50 Ma 的新年龄，以及 182.77±0.11/-0.15 的 tenuicostatum-serpentinum 带边界。