Carboniferous chemostratigraphy: Do epicontinental seas reflect global ocean conditions?

石炭纪化学地层学：陆表海是否反映全球海洋状况？Deborah J. Thomas, Ethan L. Grossman, Brent V. Miller, Thomas D. Olszewski, Thomas E. yancey - 0643309906石炭纪（3.59 - 2.99亿年前）是地球历史上构造、气候和生物发生剧烈变化的时期。从地球系统科学的角度来看，石炭纪的几个方面是独特的：以全球回归为标志的重大冰川作用的开始；碳循环的主要变化表现在古热带地区的煤聚集；大陆的重新构造导致了阿勒哈尼亚-瓦里斯坎造山运动，盘古大陆的合并，以及里海的关闭，导致北美古热带和特提斯古热带之间的海洋联系被切断。大量的古生物学、古地理和古化学数据已经产生，最近的重点是应用海洋地球化学代理来揭示构造、碳循环和气候之间的潜在联系。从理论上讲，海洋古化学资料提供了温度（δ 18氧）、碳循环（δ 13碳）和风化（34S/32S、87Sr/86Sr）的海洋代用记录，但这些代用记录来源于陆表海沉积的海洋沉积物，因此难以应用于古生代。为了支持海洋生物群落，这些浅的、陆架状的环境必须与开阔的海洋盆地（例如Panthalassa和Rheic ocean）有联系，然而有证据表明，浅海陆表海和开阔海洋之间存在地球化学脱钩。为了更好地理解石炭纪气候变化的原因和后果，pi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，他们提出要解决这个问题：石炭纪北美陆表海在多大程度上记录了全球开放海洋的状况？他们将使用不同停留时间的放射性成因和稳定同位素示踪剂，沿着横跨现今墨西哥西南部（大部分是海洋）的Mixteco地块、美国大陆中部的Arrow峡谷、伊利诺伊盆地和阿巴拉契亚盆地（大部分是内陆）的样带，来限制陆表海和公海（Panthalassa和Rheic ocean）之间的地球化学耦合程度。

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).