A Chronostratigraphic Framework for the Rise of the Ediacaran Macrobiota: New Constraints from Mistaken Point Ecological Reserve, Newfoundland
A Chronostratigraphic Framework for the Rise of the Ediacaran Macrobiota: New Constraints from Mistaken Point Ecological Reserve, Newfoundland
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DOI：
10.1130/b35646.1
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发表时间：
2021-03-01
影响因子：
4.9
通讯作者：
Condon, Daniel J.
中科院分区：
文献类型：
--
作者：
Matthews, Jack J.;Liu, Alexander G.;Condon, Daniel J.
纽芬兰东南部的Conception和圣约翰群包含了一些已知最古老的埃迪卡拉大型生物群化石。错误点生态保护区联合国教科文组织世界遗产是国际公认的化石地点，并拥有全群后生动物身体化石和后生动物运动的早期证据。错误点生态保护区的沉积序列包括类似于1500米的含化石地层，其中含有许多可确定日期的火山成因层位，因此为早期动物的崛起和多样化提供了一个重要的窗口。在这里，我们提出了六个地层连贯的放射性同位素年龄来自火山凝灰岩的概念和圣约翰集团在错误点生态保护区的锆石。最古老的建筑复杂的宏体化石，从上Drook组，有574.17 +/- 0.66 Ma的年龄（包括示踪剂校准和衰变常数的不确定性）。来自Mistaken Point生态保护区的Fermeuse地层中最年轻的范围型化石的最大年龄为564.13 +/- 0.65 Ma。著名的“E”面的化石被确认为565.00 +/- 0.64 Ma，而在Briscal组的“Brasier”面上保存异常的标本被确定为567.63 +/- 0.66 Ma。我们使用我们的新年龄来构建沉积序列的年龄-深度模型，限制沉积累积速率，并将地层化石范围转换为时间域，以便于与其他序列的时间校准数据相结合。结合这个年龄模型与编译的地层范围内的所有命名的宏体化石的错误点生态保护区继承，跨越76个离散的含化石层位，使识别和询问潜在的进化信号。高峰分类多样性内的错误点和Trepassey形成，和unitermal rangeomorphs与未显示的分支架构出现几百万年前的多终端，显示形式。总之，我们的综合地层学，古生物学和地质年代学方法提供了一个全面的，在埃迪卡拉纪中晚期的时间校准的演化记录，并在其中考虑其他地球化学，环境和演化数据集的框架。
The Conception and St. John's Groups of southeastern Newfoundland contain some of the oldest known fossils of the Ediacaran macrobiota. The Mistaken Point Ecological Reserve UNESCO World Heritage Site is an internationally recognized locality for such fossils and hosts early evidence for both total group metazoan body fossils and metazoanstyle locomotion. The Mistaken Point Ecological Reserve sedimentary succession includes similar to 1500 m of fossil-bearing strata containing numerous dateable volcanogenic horizons, and therefore offers a crucial window into the rise and diversification of early animals. Here we present six stratigraphically coherent radioisotopic ages derived from zircons from volcanic tuffites of the Conception and St. John's Groups at Mistaken Point Ecological Reserve. The oldest architecturally complex macrofossils, from the upper Drook Formation, have an age of 574.17 +/- 0.66 Ma (including tracer calibration and decay constant uncertainties). The youngest rangeomorph fossils from Mistaken Point Ecological Reserve, in the Fermeuse Formation, have a maximum age of 564.13 +/- 0.65 Ma. Fossils of the famous "E" Surface are confirmed to be 565.00 +/- 0.64 Ma, while exceptionally preserved specimens on the "Brasier" Surface in the Briscal Formation are dated at 567.63 +/- 0.66 Ma. We use our new ages to construct an age-depth model for the sedimentary succession, constrain sedimentary accumulation rates, and convert stratigraphic fossil ranges into the time domain to facilitate integration with time-calibrated data from other successions. Combining this age model with compiled stratigraphic ranges for all named macrofossils within the Mistaken Point Ecological Reserve succession, spanning 76 discrete fossil-bearing horizons, enables recognition and interrogation of potential evolutionary signals. Peak taxonomic diversity is recognized within the Mistaken Point and Trepassey Formations, and uniterminal rangeomorphs with undisplayed branching architecture appear several million years before multiterminal, displayed forms. Together, our combined stratigraphic, paleontological, and geochronological approach offers a holistic, timecalibrated record of evolution during the mid-late Ediacaran Period and a framework within which to consider other geochemical, environmental, and evolutionary data sets.