Carboniferous chemostratigraphy: Do epicontinental seas reflect global ocean conditions?

石炭纪化学地层学：陆缘海是否反映了全球海洋状况？

• 批准号: 0643309
• 负责人: Deborah Thomas
• 金额: $ 29.08万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0643309&HistoricalAwards=false
• 关键词: Carboniferous; chemostratigraphy; Do; epicontinental; seas

Carboniferous chemostratigraphy: Do epicontinental seas reflect global ocean conditions?Deborah J. Thomas, Ethan L. Grossman, Brent V. Miller, Thomas D. Olszewski, Thomas E. YanceyEAR-0643309Texas A&M UniversityABSTRACTThe Carboniferous Period (359 to 299 million years ago) was a time of dramatic tectonic, climatic, and biologic change in Earth's history. Several aspects of the Carboniferous are distinctive from the standpoint of Earth Systems Science: the onset of significant glaciation, signaled by global regression; a major change in carbon cycling manifested by coal accumulation in the paleotropics; and reconfiguration of the continents resulting in the Alleghanian-Variscan orogeny, assembly of Pangea, and closure of the Rheic Ocean, leading to severing of the marine connection between the North American paleotropics and the Tethyan paleotropics. A wealth of paleobiologic, paleobiogeographic, and paleochemical data has been generated, with recent emphasis on applying marine geochemical proxies to unraveling the potential links between tectonics, carbon cycling, and climate. The marine paleochemical data, in theory, provide oceanic proxy records of temperature (Delta 18 Oxygen ), carbon cycling (Delta 13 Carbon), and weathering (34S/32S, 87Sr/86Sr), but the application of these proxies to the Paleozoic is confounded by the fact that they are derived from marine sediments deposited in epicontinental seas. These shallow, shelf-like environments must have had connections to open ocean basins (e.g., Panthalassa and Rheic Oceans) in order to support marine communities, yet there is evidence to suggest geochemical decoupling between shallow epicontinental seas and the open ocean.In an effort to better understand the causes and consequences of climate change during the Carboniferous, PIs must first establish what can be inferred from marine geochemical records. Thus they propose to address the question, To what degree does the Carboniferous North American epicontinental sea record global open-ocean conditions? They will use radiogenic and stable isotope tracers of varying residence times along a transect spanning the Mixteco terrane in present-day southwestern Mexico (most oceanic), Arrow Canyon, US Midcontinent, Illinois Basin, and Appalachian Basin (most interior) to constrain the degree of geochemical coupling between the epicontinental sea and the open ocean (Panthalassa and Rheic Ocean).

石炭纪化学地层学：陆表海反映全球海洋状况吗？托马斯，伊森L.放大图片作者：布伦特V.米勒，托马斯D.作者：Olszewski，托马斯E.石炭纪时期（3.59亿至2.99亿年前）是地球历史上一个剧烈的构造、气候和生物变化时期。从地球系统科学的角度来看，石炭纪的几个方面是独特的：全球海退标志着重大冰川作用的开始;古热带地区煤炭积累表明碳循环的重大变化;大陆的重新组合导致了阿勒格尼-瓦里斯坎造山运动、盘古大陆的组装和莱茵洋的闭合，导致北美古热带区和特提斯古热带区之间的海洋联系被切断。已经产生了丰富的古生物学、古生物地理学和古化学数据，最近的重点是应用海洋地球化学代用品来揭示构造、碳循环和气候之间的潜在联系。从理论上讲，海洋古地球化学数据提供了海洋温度（δ 18氧）、碳循环（δ 13碳）和风化（34 S/32 S，87 Sr/86 Sr）的代用记录，但这些代用记录来源于陆表海的海洋沉积物，这一事实使它们在古生代的应用受到干扰。这些浅的、类似大陆架的环境一定与开放的海洋盆地有联系（例如，然而，有证据表明，在浅陆缘海和开阔洋之间存在着地球化学脱钩现象。为了更好地理解石炭纪气候变化的原因和后果，研究人员必须首先确定从海洋地球化学记录中可以推断出什么。因此，他们提出解决这个问题，石炭纪北美陆表海在多大程度上记录了全球开放的海洋条件？他们将使用放射性同位素和稳定同位素示踪剂的不同的停留时间沿着一个横断面跨越米斯特科维在今天的墨西哥西南部（大多数海洋），箭头峡谷，美国中部大陆，伊利诺伊盆地和阿巴拉契亚盆地（大多数内部），以限制地球化学之间的耦合程度的陆表海和开放的海洋（泛萨拉萨和Rheic海洋）。