Upper Cambrian Faunal Patterns on the Craton

Research Article| November 01, 1970 Upper Cambrian Faunal Patterns on the Craton CHRISTINA LOCHMAN-BALK CHRISTINA LOCHMAN-BALK New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1970) 81 (11): 3197–3224. https://doi.org/10.1130/0016-7606(1970)81[3197:UCFPOT]2.0.CO;2 Article history received: 24 Jul 1969 rev-recd: 02 Jul 1970 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation CHRISTINA LOCHMAN-BALK; Upper Cambrian Faunal Patterns on the Craton. GSA Bulletin 1970;; 81 (11): 3197–3224. doi: https://doi.org/10.1130/0016-7606(1970)81[3197:UCFPOT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Analysis of the biostratigraphy and the litho-facies pattern of Upper Cambrian sedimentation upon the craton reveals four synchronous marine regressions and three transgressions attributable to eustatic sea level change. The beginning of each regression relates to the impoverishment or extinction of the existing trilobite biota and the appearance of many individuals of a few unrelated genera and species. Except in near-shore sites the abrupt faunal change preceded by a short time the physical evidence of regression in the sections. The cause of the faunal change and of the regression was a deterioration of world climate.The first regression occurred during the Bolaspidella Zone and the ensuing faunal impoverishment and change has been used to mark the end of the Middle Cambrian. The beginning of the second regression coincided with the appearance of the oldest genera of the Aphelaspis Zone assemblage on the craton in late Dresbachian; the third with the earliest genera of the Conaspis Zone assemblage in the middle Franconian; and the fourth with the dominance of genera of the Hungaia assemblage on the craton in late Trempealeauan. The small biota of each new assemblage evolved during the regression to occupy the limited habitats of the shrinking environments on the craton and in the adjoining miogeosyncline. During the succeeding transgression some of the genera evolved explosively as a variety of habitats became available in the warming marine waters of the expanding cratonic environment. The Cedaria-Crepicephalus, the Elvinia, and the Prosautya-early Saukja assemblages are the characteristic, highly varied biotas of the transgressions. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.