A Dinoflagellate Cyst Zonation of the Cenomanian and Turonian (Upper Cretaceous) in the Western Interior, United States
A Dinoflagellate Cyst Zonation of the Cenomanian and Turonian (Upper Cretaceous) in the Western Interior, United States
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DOI：
10.1080/01916122.2018.1477851
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发表时间：
2019-01
期刊：
影响因子：
1.5
通讯作者：
P. Dodsworth;J. Eldrett
中科院分区：
文献类型：
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作者：
P. Dodsworth;J. Eldrett
摘要这项研究记录了美国科罗拉多州普韦布洛以西岩石峡谷背斜露头的桥溪段格林霍恩石灰岩组的详细孢粉学。该剖面是正式批准的全球界线层型剖面和点(GSSP)，适用于吐鲁尼亚阶段和相应的下吐鲁尼亚亚阶段的底部，也是唯一提议的用于中吐鲁尼亚亚阶段底部的GSSP。回顾了作者以前发表的来自附近美国地质调查局(USGS)波特兰1号岩心下的Cenomian地层的孢粉资料，以及德克萨斯州西南部Cenomian、Turonan和最早的Coniacian时代的岩心和露头的生物地层学。根据其他公布的生物和化学地层(碳同位素)数据和天文年龄模型，对这两个地区的甲藻包囊范围和事件进行了校准。根据中欧和北欧的方案，提出了一个地区性的甲藻包囊分带，包括三个带和四个亚带。与亚利桑那州、堪萨斯州、犹他州、怀俄明州和蒙大拿州等其他州公布的古旧孢粉数据进行比较，表明该分区可能适用于美国白垩纪西部内海的海洋剖面。普韦布洛中-下图罗尼亚边界附近的新孢粉学数据支持其作为全球科学计划的提议。
ABSTRACT This study documents the detailed palynology of the Bridge Creek Member, Greenhorn Limestone Formation, at the Rock Canyon anticline outcrop, west of Pueblo, Colorado, USA. The section is the formally ratified Global Boundary Stratotype Section and Point (GSSP) for the base of Turonian Stage and corresponding Lower Turonian Substage, and the only proposed GSSP for the base of the Middle Turonian Substage. The authors' previously published palynological data from the underlying Cenomanian strata in the nearby US Geological Survey (USGS) Portland-1 core, and from cores and an outcrop of Cenomanian, Turonian and earliest Coniacian age in SW Texas, are reviewed for biostratigraphy. Dinoflagellate cyst ranges and events in both areas are calibrated against other published bio- and chemostratigraphical (carbon isotope) data and an astronomical age model. A regional dinoflagellate cyst zonation is proposed, adapted from a Central and Northern European scheme, comprising three zones and four subzones. Comparison with vintage published palynological data from other states, including Arizona, Kansas, Utah, Wyoming and Montana, indicates that the zonation is probably applicable to marine sections throughout the Cretaceous Western Interior Seaway of the USA. The new palynological data from around the Lower–Middle Turonian boundary at Pueblo support its proposal as a GSSP.