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首页> 外文学位 >Organic-walled microplankton in the Jaguel Formation (upper Maastrichtian-Danian), Neuquen Province, Argentina: Implications for the Cretaceous/Paleogene boundary event.
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Organic-walled microplankton in the Jaguel Formation (upper Maastrichtian-Danian), Neuquen Province, Argentina: Implications for the Cretaceous/Paleogene boundary event.

机译：阿根廷内乌肯省Jaguel组（马斯特里赫特-达安上部）中的有机壁微浮游生物：对白垩纪/古生界事件的影响。

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摘要

Fossil organic-walled microplankton, dinoflagellates primarily, from marine deposits of the Jaguel Formation at two locations, Lomas Coloradas and Bajada de Jaguel, Neuquen Province, Argentina, were analyzed for age assignment, paleoenvironmental interpretation and paleobiogeography of selected species.; The abundant and diverse dinoflagellate cyst assemblages show that the Jaguel Formation is of Late Maastrichtian/Danian age and contains the Cretaceous/Paleocene boundary. The precise location, at the Bajada de Jaguel section, of a biologic turnover that is interpreted to represent the Cretaceous/Paleogene boundary event occurs at the bottom of a 17cm water lain ash layer and is defined on the basis of the first occurrence of worldwide known Danian dinocyst biostratigraphic markers such as Damassadinium californicum and Senoniasphaera inornata. Detailed studies of the dinoflagellates recovered show that the group was more resistant than the calcareous microfossils to the Cretaceous/Paleogene boundary event and did not suffer mass extinction. This is probably because they are represented in the fossil record only by the encysted stage. However, dinoflagellates did undergo a sharp turnover with extinction of some species and migration of others. Locally, the last occurrence of Maastrichtian autotrophic, the gonyaulacacean affinity group, appears to be severely affected by the K/Plg boundary event. With the exception of Deflandrea galeata and the Isabelididnium-Manumiella complex, the peridinialean affinity group, considered as heterotrophic, survived the event.; Within 1m interval below the boundary, the first occurrence, peak and disappearance of the Isabelidinium/Manumiella group was documented. This group evolved through the Upper Cretaceous at high latitudes and its presence is interpreted as indicating a short-term episode of regression and/or water cooling prior to the boundary.; Within the 2m interval above the boundary, an unusual peak of acritarchs, single celled and colonial algae and small peridiniod species bloom are interpreted as the response to environmental stress in the aftermath of the boundary event.; Comparisons with studies in sections from the Southern Hemisphere suggest that temperature and/or salinity barriers controlled the paleogeography of the assemblages. The assemblages from Tierra del Fuego and Antarctica are very similar to one another, but differ from those of middle latitude analyzed in this study.
机译：分析了阿根廷内乌肯省Lomas Coloradas和Bajada de Jaguel两个地点的Jaguel组海洋沉积物中主要为鞭毛虫的化石有机壁微浮游生物的年龄分配，古环境解释和所选物种的古生物地理。丰富而多样的异鞭毛虫囊肿组合表明，Jaguel组处于马斯特里赫特晚期/达尼安时代，并包含白垩纪/古新世边界。在Bajada de Jaguel断面的生物翻转的精确位置被解释为代表白垩纪/古生物学的边界事件，发生在17cm的层积水灰层的底部，并且是根据第一次世界范围内已知的事件定义的丹尼亚恐龙囊生物地层标记物，例如Damassadinium californicum和Senoniasphaera inornata。对回收的鞭毛藻的详细研究表明，该组比白垩质微化石对白垩纪/古生界的边界事件更有抵抗力，并且没有灭绝。这可能是因为它们仅在化石阶段才在化石记录中代表。但是，鞭毛藻确实发生了急剧的周转，其中一些物种灭绝而另一些物种迁徙。在本地，最后一次出现的马斯特里赫特自养生物，即冈拉西坦亲和性基团，受到K / Plg边界事件的严重影响。除Deflandrea galeata和Isabelididnium-Manumiella复合体外，被认为是异养性的周二亲和性基团在事件中幸存下来。在边界以下1m的间隔内，记录了Isabelidinium / Manumiella组的首次出现，峰和消失。该组在高纬度地区通过上白垩统演化，其存在被解释为表明边界发生短期回归和/或水冷现象。在边界以上2m的间隔内，尖锐的尖锐的尖峰，单细胞和殖民藻类以及小的周生物种的花被解释为边界事件发生后对环境压力的响应。与南半球各部分研究的比较表明，温度和/或盐分屏障控制着该组合的古地理。火地岛和南极洲的组合非常相似，但与本研究中分析的中纬度组合不同。

著录项

  • 作者

    Palamarczuk, Susana.;

  • 作者单位

    City University of New York.;

  • 授予单位 City University of New York.;
  • 学科 Paleontology.; Geology.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 220 p.
  • 总页数 220
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 古生物学;地质学;
  • 关键词

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