Biostratigraphy and Mass Extinction Pattern across the Cretaceous/Paleogene Boundary, Northern Alborz, Iran

Masoud Asgharian Rostami,Mohammad Vahidinia,Abbas Sadeghi,Ebrahim Ghasemi-Nejad

doi:10.4236/ojg.2013.31005

Abstract

High resolution sampling across the Cretaceous/Paleogene boundary (K/Pg) at the Galanderud section in northern Iran provides the most expanded and continuous section for us to consider biostratigraphy and the mass extinction pattern of Cretaceous planktic foraminifera. Based on planktic foraminifera, four biozones and five sub-biozones have been identified across the K/Pg boundary. These biozones include the Abathomphalus mayaroensis Biozone (Plummerita hantkeninoides subbiozone), the Guembelitria cretacea Biozone (including two sub-biozones: the Hedbergella holmdelensis and the Parvularugoglobigerina longiapertura), the Parvularugoglobigerina eugubina Biozone (including two subbiozones: the Parvularugoglobigerina Sabina and the Eoglobigerina simplicissima) and finely the Parasubbotina pseudobulloides Biozone. Planktic foraminiferal extinction occurred over a brief period, with 3% of the species disappearing in the late Maastrichtian, and 72% of the species becaming extinct at the K/Pg boundary. About 25% of the species survived into the early Danian. Extinction of 73% of the species at the K/Pg boundary is very compatible with the effect of a large asteroid impact.

Highlights

The Cretaceous-Paleogene boundary (K/Pg) is one of the major crises in the history of life on Earth
High resolution sampling across the Cretaceous/Paleogene boundary (K/Pg) at the Galanderud section in northern Iran provides the most expanded and continuous section for us to consider biostratigraphy and the mass extinction pattern of Cretaceous planktic foraminifera
Based on planktic foraminifera, four biozones and five sub-biozones have been identified across the K/Pg boundary

Summary

Introduction

The Cretaceous-Paleogene boundary (K/Pg) is one of the major crises in the history of life on Earth. The proposed causes of this mass extinction are widely considered as a combination of degassing of the Deccan Traps and a bolide impact in Chicxulub, Mexico [1]. Alvarez and his colleagues [2] suggested the bolide impact theory as the cause for the mass extinctions at Cretaceous-Paleogene boundary. This meteorite impact is evidenced by anomalous abundance of Ir, microtektites, shocked quartz and Ni-rich spinels in K/Pg boundary deposits. The aim of this paper is to determine the biostratigraphy and model the extinction pattern of planktonic foraminiferal species in the Galanderud section

Objectives

Methods

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Conclusion