Palustrine Sediments between Two Isolated Shallow Carbonate Platforms (Aptian–Albian Transition, Prebetic of Jaén, South Spain)

Luis M Nieto,José Miguel Molina,Matías Reolid,José Manuel Castro,Ginés A De Gea,Pedro Alejandro Ruiz-Ortiz

doi:10.3390/min12020116

Abstract

During the Aptian-Albian transition, an extensional phase of the Central Atlantic which affected the Prebetic carbonate platform (South Iberian Continental Margin, northwestern margin of the Tethys) occurred. A graben morphology was developed in the platform coeval to a relative sea level fall. As a consequence, palustrine facies characterized by rhizoliths and some pond deposits of black lutites were established. Over these palustrine sediments, a second shallow carbonate platform was built during the early Albian. However, this process was not abrupt, as several levels with orbitolines and rudists were deposited intercalated between the continental facies, recording the transition to a new shallow marine carbonate platform developped during the Early Albian. The presence of these continental palustrine sediments between two episodes of shallow carbonate platform is described for the first time in the Prebetic. The demise of an upper Aptian isolated shallow carbonate platform drove to the deposition of these palustrine sediments in an extensional tectonic regime.

Highlights

The Aptian–Albian transition is an interesting interval at a global scale, which records the occurrence of the Oceanic Anoxic Event 1b, associated to a global perturbation of the carbon cycle and regional deposition of organic-rich deposits, in the western Tethys [1]
In the Sierra de Bedmar-Jódar, the most important feature during the Aptian–Albian transition is the presence of a continental record of palustrine sediments with paleosols, covering sediments deposited in a carbonate platform
After the analysis of the stratigraphy, sedimentology and paleontology of this palustrine sediments and of their meaning in the evolution of this area of the Southern Iberian Continental Margin (SICM), we propose a demise model of carbonate platforms, which differs from that proposed for other Tethys perimediterranean platforms

Summary

Introduction

The Aptian–Albian transition is an interesting interval at a global scale, which records the occurrence of the Oceanic Anoxic Event 1b, associated to a global perturbation of the carbon cycle and regional deposition of organic-rich deposits, in the western Tethys [1]. This interval records a remarkable climate change toward more humid and warm conditions after the cooling snap of the late Aptian [2], and a notable biotic turnover in marine faunas [3]. This extensional pulse is related to the opening of the Central Atlantic and the development of the Alpine Tethys rift [7], when the connection between the Tethys and the Central and South Atlantic was being generated

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