Great revolution of Early Ordovician geobiota in the Yangtze Block, China: the establishment of land - sea linkages

2014 Fiscal Year Final Research Report

• Project/Area Number: 24340130
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Osaka City University
• Principal Investigator: EZAKI Yoichi 大阪市立大学, 大学院理学研究科, 教授 (60221115)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 環境変動 / 揚子地塊 / オルドビス紀 / カンブリア紀 / 微生物岩 / 礁 / ストロマトライト

Outline of Final Research Achievements

To understand the Early Ordovician great revolution in geobiota in the Yangtze Block, this project examined the genesis of and secular changes in lower Cambrian reefs in the block, and in middle to upper Cambrian reefs in the North China Block. In the former, purely calcimicrobial reefs formed after the demise of archaeocyathan reefs, related to a late early Cambrian regression. In contrast, the latter saw the development of sponge - microbial reefs earlier than elsewhere. The sponge - microbial reefs were precursors of those that dominated worldwide in the Early Ordovician, when terrestrial-derived nutrients showed a marked increase through land - sea linkages. The low preservation potential of sponges provided a substrate for the development of reef-builders. In addition, the growth forms and morphological variability of reef constructors increased markedly. The establishment of such reef-building patterns also would have made a large contribution to the Early Ordovician revolution.

Free Research Field

層位・古生物学