Spatial variation in the diversity and composition of the Lower Cambrian (Series 2, Stage 3) Chengjiang Biota, Southwest China
Spatial variation in the diversity and composition of the Lower Cambrian (Series 2, Stage 3) Chengjiang Biota, Southwest China
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中国西南地区下寒武统（系列2，第3阶段）澄江生物群多样性和组成的空间变化
DOI：
10.1016/j.palaeo.2012.05.021
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发表时间：
2012-08-15
影响因子：
3
通讯作者：
Lu, Miao
中科院分区：
文献类型：
--
作者：
Zhao, Fangchen;Hu, Shixue;Lu, Miao
下寒武统澄江生物群（玉安山组茅田页岩段）（第2统第3期）的地层分布于中国西南部的云南省东部。在这项研究中，基于文献的动物区系清单从10个地区（代表34个地点），连同22,038个新标本收集在三个地点从10个地区的三个，进行了定量分析，以评估大规模的空间变异的分类多样性和组成。我们的分析表明，当地的古环境和物种多样性之间存在着显著的协变，并建议在毛天山页岩段中存在三个一般的埋藏相，从西到东：低多样性26种，是武定地区的特征，该地区的含油气地层经历了广泛的生物扰动;高度多样性澄江-海口-安宁地区的含油气地层主要由事件层和背景泥岩薄层叠置而成，有215种;中等多样性（55种）是马龙地区的特征，其中含油气地层由不明显的层状页岩组成，显示出较少的单事件层，但丰富的背景层。尽管站点之间的采样工作的变化，在物种多样性和群落组成的空间格局主要由沉积环境的变化控制，沿着近端近海较低的滨面梯度，影响生态和埋藏因素。近海环境（海口-澄江-安宁地区）显示出相对较高的物种多样性和异常保存的软体化石，反映了在远源风暴岩中的快速埋藏。相对较高程度的生物扰动，时间平均和水动力扰动造成了大幅度下降，在武定和马龙地区的保存质量和软体动物物种的数量。研究表明，澄江生物群在分类多样性、区系组成和化石保存等方面的空间变异具有很好的高分辨率特征。此外，澄江生物群可能提供了一个独特的机会，以评估的作用，环境因素，埋藏和生态控制的物种多样性在地方到区域的空间尺度。(C)2012 Elsevier B. V.保留所有权利。
Strata hosting the Lower Cambrian (Series 2, Stage 3) Chengjiang Biota (Maotianshan Shale Member, Yu'anshan Formation) occur throughout the eastern part of Yunnan Province, Southwest China. In this study, literature-based faunal inventories from 10 areas (representing 34 localities), together with 22,038 new specimens collected at three localities from three of the 10 areas, were analyzed quantitatively to assess large-scale spatial variation in taxonomic diversity and composition. Our analyses show substantial co-variation between local paleoenvironmental settings and species diversity, and suggest the presence of three general taphofacies in the Maotianshan Shale Member, from west to east: low diversity (26 species) characterizes the Wuding area, where fossiliferous strata have undergone extensive bioturbation; high diversity (215 species) characterizes the Chengjiang-Haikou-Anning areas, where fossiliferous strata consist of stacked couplets of thin event and background mudstone layers; moderate diversity (55 species) characterizes the Malong area, where fossiliferous strata consist of indistinctly bedded shale showing fewer single-event layers but abundant background layers. In spite of variations in sampling effort between sites, spatial patterns in species diversity and community composition were controlled primarily by variation in depositional environments along a proximal offshore to lower shoreface gradient, which influenced both ecological and taphonomic factors. The offshore settings (Haikou-Chengjiang-Anning areas) show relatively high species diversity and exceptional preservation of soft-bodied fossils, reflecting rapid burial in distal tempestites. Relatively high degrees of bioturbation, time-averaging and hydrodynamic disturbance caused a substantial decrease in the quality of preservation and number of soft-bodied species in the Wuding and Malong areas. Arthropods are the most diverse group in most localities, followed by priapulids, poriferans, brachiopods, lobopods and hyoliths.This study shows that the Chengjiang Biota lends itself very well to high resolution characterization of spatial variation in taxonomic diversity, faunal composition and fossil preservation. Furthermore, the Chengjiang Biota may provide a unique opportunity to assess the roles of environmental factors, taphonomy and ecological controls on species diversity at local to regional spatial scales. (C) 2012 Elsevier B.V. All rights reserved.