Intrastratal trace fossil zonation, Cretaceous flysch of northern California
作者:
William Miller,
期刊:
Ichnos
(Taylor Available online 1991)
卷期:
Volume 1,
issue 3
页码: 161-171
ISSN:1042-0940
年代: 1991
DOI:10.1080/10420949109386349
出版商: Taylor & Francis Group
关键词: vertical zonation;disturbance;infaunal tiering;pre‐ versus post‐turbidite trace fossils;flysch;Cretaceous;California
数据来源: Taylor
摘要:
Dissection of fine‐grained turbidites within the Franciscan complex at Trinidad Harbor reveals intrastratal zonation of biogenic structures. The pre‐depositional association comprises only three ichnotaxa (preserved in convex hyporelief) and is less diverse than the tiered post‐depositional association (comprised by at least seven ichnotaxa preserved in full relief). The latter association is dominated byMelatercichnus(n. ichnogen.). Post‐depositional trace‐makers exploited abundant plant detritus deposited with the turbidite sand. Temporal alternation of trace fossil associations resulted from the infrequent, but catastrophic, disturbance of pre‐turbidite communities and local replacement by assemblies of opportunistic organisms. Although probably short‐lived at specific sites, the post‐turbidite infauna was tiered, enabling a variety of deposit feeders to harvest phytodetritus of varied size or density simultaneously at different depths within newly deposited turbidite sand layers.
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