地史学教学课件-地史学10.pptVIP

第7章 早古生代的地史Early Paleozoic geohistory ;7.1 Early Paleozoic abstract;志留纪（Silurian,S） Murchison, 1835, 英国古民族名称 奥陶纪（Ordovician,O） Lapworth, 1879，英国古民族名称 寒武纪（Cambrian,∈） Sedgwick, 1835， Cambria山 早古生代持续126Ma;显生宙各纪命名地点;Phanerozoic global chronostratigraphic boundaries are formally defined by a Global Standard (Boundary) Stratotype Section and Point (GSSP - COWIE et al, 1986), whereas Precambrian chronostratigraphic boundaries are formally defined in terms of absolute ages : Global Standard Stratigraphic Age (GSSA- REMANE et al, 1996). In order to become mandatory, a boundary definition as to be accepted by 60% majority in successive votes, first by the working group responsible for the choice of the GSSP, then by the concerned Subcommission of ICS and finally by the Full Commission of ICS. With its ratification(批准） through IUGS, the GSSP or GSSA becomes mandatory（强制性的）.;1 生物界—寒武纪生物大暴发(Cambrian explosion）；海生无脊椎动物空前繁盛（环境分析、地层对比、生态分异、生物分区);植物登陆；奥陶纪末期生物集群绝灭(mass extinction)事件 2 属加里东(Caledonian)构造阶段，陆壳板块扩大和增生（陆相沉积、生物上陆） 3 沉积类型复杂多样，奥陶纪末期冈瓦纳 (Gondwana)大陆发育冰川;第7章 早古生代的地史Early Paleozoic geohistory ;Primarily confined to shallow-water marine environments. Animals with hard body parts appear at the beginning of the Cambrian - this defines the beginning of the Phanerozoic. Important fossils: trilobites, graptolites, Cephalopods (mainly nautiloids), conodonts, brachiopods Other fossils: Mollusca, corals, Arthropoda, Echinodermata, Vertebrata，sponges;1 小壳动物群(small shell-bearing fauna)：震旦纪末期出现、寒武纪初大量繁盛，个体微小（1—2mm），具外壳的多门类海生无脊椎动物群。包括软体动物门中的软舌螺、单板类和腹足类，腕足类以及分类位置不明的类型。 意义：第一个带壳生物群，寒武纪的起点;早期小壳动物群small shell-bearing fauna（与伊迪卡拉动物群共生）;;寒武系底部继小壳动物群之后出现的第一个无壳和具壳化石混生化石群。包括三叶虫、水母、蠕虫类、甲壳纲及分类位置不明的节肢动物、腕足类、藻类及脊索动物----鱼。最早发现于云南澄江 意义：是寒武纪初期生物大爆发的典型代表;叶足动物门，Microdictyon sinicum Chen, Hou et Lu,1989;澄江动物群;澄江动物群;澄江动物群; 澄江动物群中的昆明鱼化石; 澄江动物群中的海口鱼化石;Chengjiang fauna;帽天山;澄江动物群;;澄江动物群生态复原;三叶虫是继小壳动物后最早繁盛的带壳动物 寒武纪三叶虫属种繁多，演化迅速，生态分异明显，是寒武纪地层划分对比