澄江生物群分子在贵州遵义牛蹄塘组发现   总被引：8，自引：1，他引：7  

杨瑞东张位华  姜立君高慧 《地质学报》2003,77(2):145-150,T001

澄江生物群是认识寒武纪生命大爆发的重要窗口,它的分布范围一直仅限于滇东地区,员近在贵州遵义松林牛蹄塘组底部页岩中发现有Naronia,Archotuba Conoidalis,Isaxys,Perpicaris,Lingulepis,Tsunyidiscus,Scenella,水母状化石(medusiform fossil),海绵动物化石Leptomitus,类似半索动物秆壁虫Rhabdopleura化石,软舌螺类Hyolithids,宏观藻类和疑源类化石Zunyiphyton perelegans Yang et Zhao,1999,Yuknessia sp.,Longenema Ding,1996,Sphaerocongregus variabilis等。其中有一部分是属于澄江生物群分子,这是云南省外澄江生物群分子的新发现。由于生物群之下40m处还产大量海绵动物、高肌虫和藻类化石等组成的松林生物群,其上又有下寒武统明心寺组古杯动物群,因此,这一生物群的发现对研究早寒武世生物的演化也具有一定的科学意义,同时,对澄江生物群的古生态学研究也具有重要意义。  相似文献   

What happened to climate change? CITES and the reconfiguration of polar bear conservation discourse     

《Global Environmental Change》2014

In the past decade, polar bears have become the poster species of climate change. But in March 2013, a joint proposal by the governments of the United States and the Russian Federation to up-list polar bears to Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) diverted public attention from climate change towards the hunting of polar bears. Prior to a vote on the proposal, non-governmental organisations spear-headed a media campaign to support the up-listing. In the United Kingdom the campaign received support from celebrities and was widely reported in English language news media. Narratives of commercial legal and illegal polar bear hunting and the imminent extinction of polar bears were aggressively promoted, rhetorically supported by the manipulation of trade and scientific data. By rendering discourses of commercial hunting and a lucrative global trade in polar bear parts highly visible, sustainable hunting and climate change-induced habitat loss were rendered invisible. Media reports of commercial hunting de-coupled polar bear conservation from climate change mitigation, and disassociated polar bear hunting from regulated indigenous subsistence practices. A review of current polar bear conservation measures and an analysis of media coverage leading up to the CITES decision reveal these conflicting discourses, and suggest that more nuanced media coverage of polar bear conservation is necessary if appropriate multilateral conservation policies are to be enacted and publicly supported.  相似文献   

大山口剪切带大理岩糜棱岩的变形机制分析     

殷秀兰 《地质力学学报》1996,2(4):61-67

大山口韧性剪切带是大别造山带"结晶轴带"内平行造山带延长方向的走滑型剪切带,其内发育的大理岩糜棱岩呈现了各种在绿片岩相变质条件下形成的显微构造,如碎斑构造、S-C组构、核幔构造等。糜棱岩化作用是以方解石颗粒粒度的减小为特征的,这一过程表现了大别造山带古老中地壳应变软化带和局部化带的岩石流变行为和物理状态。根据各种显微标志,并综合宏观特征,得出大山口剪切带总体为以右行剪切为主的走滑型剪切带,并被以正向滑动为主的近水平剪切带所改造。
作者在综合分析宏观及微观地质资料的基础上,初步建立了广水地区主要地质及变形事件序列,并指出:大别造山带三维空间上的变形及结构图象,主要是印支-燕山期陆-陆俯冲、碰撞造山运动的变形及造山期后的揭顶、塌陷等作用的综合结果。   相似文献   

鄂西早三叠世南漳-远安动物群地层分布特征          下载免费PDF全文

阎春波  李姜丽  程龙  赵璧  邹亚锐  牛东毅  陈刚  方子晨 《地球科学》2021,46(1):122-135

在区域地质调查的基础上,以远安张家湾嘉陵江组剖面为重点,通过对南漳和远安交界地区下三叠统嘉陵江组剖面测制和多处化石点考察,重新厘定研究区内嘉陵江组岩性特征.认为研究区内的嘉陵江组划分为3个岩性段更为合理,产南漳-远安动物群的纹层状灰岩段位于二段顶部.通过系统化石发掘和张家湾剖面详细描述,初步查明了南漳-远安动物群的垂向...  相似文献