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首页> 外文学位 >Dinoflagellates from the Upper Campanian - Maastrichtian of Colombia and western Venezuela: Biostratigraphic and sequence stratigraphic implications.
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Dinoflagellates from the Upper Campanian - Maastrichtian of Colombia and western Venezuela: Biostratigraphic and sequence stratigraphic implications.

机译：来自上Campanian-哥伦比亚马斯特里赫特和委内瑞拉西部的鞭毛虫：生物地层学和层序地层学意义。

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摘要

Dinoflagellate biostratigraphy of the Upper Campanian-Danian was studied in five surface sections from Colombia and one from western Venezuela (Rio Loro section). The Rio Molino section is in northern Colombia, the Chiguata Creek and Tausa sections are in the central part of the Eastern Cordillera, La Buitrera Creek section is in the western flank of the Eastern Cordillera, and the Aico Creek Section is in the Upper Magdalena Valley. At least twenty-two biostratigraphically significant events were identified in the upper Campanian and Maastrichtlan of the studied sections. In absence of calcareous macro- and microfossils the Campanian/Maastrichtian boundary was identified based on the highest occurrence of Trichodinium castanea and near the lowest occurrence of Phelodinium tricuspe, Yolkinigymnium lanceolatum and Hafniasphaera fluens. Several third-order coarsening upward cycles were recognized within the overall shallowing upward pattern displayed in the six sections. Dinoflagellates tend to be more abundant at the base of these cycles and peridinoid cysts dominate the dinoflagellate assemblage in most samples. During the upper Campanian carbonate sediments accumulated in northern Colombia (Socuy Limestones), while high paleo-productivity conditions generated biosiliceous sediments and condensed phosphorites in the Eastern Cordillera and the Upper Magdalena Valley (Plaeners Formation and Lidita Superior). These become younger to the east. Continuous, cyclic progradation from the east and south during the upper Campanian accumulated coarse-grained siliciclastics in proximal settings where sandstones are interbedded with porcelanites and cherts (Chiguata and Tausa sections). In more distal environments, micritic limestones and dark mudstones from the Buscavida Formation represent coeval sediments (La Buitrera Creek and Alco Creek sections). An expanded section of mudstones and sandstones from Los Pinos and Tierna Formations was recognized in the Chiguata Creek section relative to the Aico, La Buitrera, Rio Molino and Tausa sections. The K/T boundary is present in the Venezuelan section but coincides with an 11.5 m unexposed interval separating uppermost Maastrichtian dinoflagellate events below from Danian dinoflagellates above.
机译：在哥伦比亚的五个地表剖面和委内瑞拉西部的一个地表剖面（里奥洛罗剖面）研究了上坎帕尼-达尼安的鞭毛藻生物地层学。 Rio Molino段位于哥伦比亚北部，Chiguata Creek和Tausa段位于东部山脉的中部，La Buitrera Creek段位于东部山脉的西侧，Aico Creek段位于上马格达莱纳谷。在研究断层的上Campanian和Maastrichtlan地区至少发现了22个生物地层学重要事件。在不存在钙质大型化石和微化石的情况下，根据 Trichodinium castanea 的最高发生率和 Phelodinium tricuspe，Yolkinigymnium lanceolatum 和< italic> Hafniasphaera fluens 。在六个部分显示的总体浅化向上模式中，识别出几个三阶粗化向上循环。在这些周期的基础上，鞭毛藻往往更丰富，在大多数样品中，鞭毛类囊肿主导着鞭毛藻的组合。在哥伦比亚北部的上部坎帕尼亚碳酸盐沉积物（苏古石灰岩）中积累，而高古生产力条件在东部山脉和上马格达莱纳谷地（普拉纳斯组和利迪塔特优）产生了生物硅质沉积物和凝结的磷矿。这些在东方变得年轻。在上坎潘期期间，从东部和南部连续不断的循环堆积，在近端环境中堆积了粗粒状硅质碎屑岩，砂岩夹杂着角砾岩和石（Chiguata和Tausa剖面）。在更远端的环境中，来自Buscavida组的微粉质石灰岩和深色泥岩代表着中世纪的沉积物（La Buitrera Creek和Alco Creek断面）。相对于Aico，La Buitrera，Rio Molino和Tausa断层，在Chiguata Creek断层中认识到了Los Pinos和Tierna地层的泥岩和砂岩扩展段。委内瑞拉部分存在K / T边界，但与11.5 m的未暴露间隔一致，该间隔将下面的最上Maastrichtian鞭毛藻事件与上面的大鞭毛藻分开。

著录项

  • 作者

    Yepes, Oscar.;

  • 作者单位

    Texas A&M University.;

  • 授予单位 Texas A&M University.;
  • 学科 Palynology.; Paleontology.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 237 p.
  • 总页数 237
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 植物形态学;古生物学;
  • 关键词

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