Document Type

Article

Publication Date

3-2012

Publication Title

SEPM (Journal of Sedimentary Research)

Abstract

Global perturbations during the Cenomanian–Turonian boundary (CTB) interval and the Oceanic Anoxic Event 2 (OAE 2) represent one of the most extensively studied past environmental changes. To explore the response of various carbonate-platform depositional systems to such major environmental perturbations, strata of the intra-Tethyan Adriatic carbonate platform (sensu stricto) from the island of Bracˇ (Adriatic Sea, Croatia) provide excellent exposures and a previously well-established Upper Cretaceous lithostratigraphic framework. Within this context, this study integrated lithostratigraphy, biostratigraphy, and chemostratigraphy to describe a drowned-platform succession underlain and overlain by peritidal carbonates. Carbon-isotope stratigraphy of this succession revealed a shift towards positive d13C values that reached +4 to +5% VPDB, and represent the CTB interval excursion plateau.

We observed variations in thickness of the drowned-platform successions and explained them by three superimposed mechanisms: (1) diachronous drowning of platform relief; (2) intra-platform redeposition of parts of the successions by various mass-gravity transport processes (indicating enhanced instability due to increasing accommodation space related to the late Cenomanian platform drowning and synsedimentary tectonics); and (3) migration of major carbonate factories during the recovery of shallow-platform environments. The results indicate that the CTB interval event caused unusual increase in accommodation space on the carbonate platform enabling open-marine influence and synsedimentary redeposition. However, widespread organic-rich black shales reported from coeval strata of other regions have not been documented from the platform-top successions to date, and were probably accumulated in deeper (anoxic) settings below the rising sea level.

Volume

82

First Page

163

Last Page

176

DOI

10.2110/jsr.2012/17E 2012, SEPM (Society for Sedimentary Geology)

Rights

©2012, SEPM (Society for Sedimentary Geology)

Comments

Archived as published. Open access article.

Included in

Geology Commons

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.