Middle and Late Cambrian Depositional Environments and Trilobite Faunas of the Fenghuang – Chenxi, Western Hunan, China

Middle and Late Cambrian trilobite faunas are described from the Dama, Haichongkou Elitang and Shishangguan (Chenxi) sections in western Hunan. There, trilobites are the most common macrofossils and include a mixture of cosmopolitan agnostoids and polymerids, most of the fossils are well preserved in dark gray or gray granular, laminated, argillaceous carbonates. The trilobite faunas are assigned to 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Three new species are described by author in 2004. the discovery of this genus is significant for biostratigraphic correlation of the Late Cambrian in the Australo-Asia region.
During the Middle and Late Cambrian, the study area had well-developed carbonate gravity deposits, particularly in the Fenghuang and adjacent areas. This paper describes in detail slope fan deposit characters of the Lejopyge laevigata to Corynexochus plumula-Sinoproceratopyge cf. kiangshanensis zones. According to their distribution and thickness, three main slope fan deposits have been recognized in the study area.
According to vertical distribution regularity, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for Dama section and 4 trilobite communities for Haichongkou section.

【Main Contents】

Chapter 1 Introduction
1.1 Previous studies
1.2 Regional geologic setting
1.3 Purpose of study
1.4 Collections
Chapter 2 Lithostratigraphy
2.1 Description of sections
2.2 Major lithostratigraphic units of the study area
Chapter 3 Biostratigraphy
3.1 Trilobite zones of the study area
3.2 Correlation
Chapter 4 Carbonate Platform Margin Slope Deposits and Palaeogeography
4.1 Characteristics of the rock associations
4.2 Marine carbonate facies group
4.3 Evolution of the depositional environments
Chapter 5 Trilobite Communities and Palaeoenvironments
5.1 Introduction
5.2 Trilobite communities from the Dama Section
5.3 Trilobite communities from the Haichongkou Section
5.4 Comment on palaeoenvironments of the study area
Chapter 6 Systematic Paleontology