2006 Philadelphia Annual Meeting (22–25 October 2006)
Paper No. 182-1
Presentation Time: 8:00 AM-8:15 AM

INITIAL SURVIVORSHIP OF NONMARINE MOLLUSCAN FAUNAS IN END-CRETACEOUS DECCAN INTERTRAPPEAN STRATA, INDIA

HARTMAN, Joseph H.1, MOHABEY, Dhananjay M.2, BINGLE, Marron1, SCHOLZ, Henning3, BAJPAI, Sunil4, and SHARMA, Ritu4, (1) Department of Geology and Geological Engineering, University of North Dakota, 81 Cornell Street Stop 8358, Grand Forks, ND 58202, marron.bingle@und.edu, (2) Palaeontology Division, Geological Survey of India, Seminary Hills, Nagpur, 440 006, India, (3) Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstrasse 43, Berlin, 10115, Germany, (4) Department of Earth Sciences, Indian Institute of Technology, Uttaranchal, Roorkee, 247667, India

The record of nonmarine mollusks from the Deccan Plateau of peninsular India has remained poorly known since their initial study in the mid-1800s. With more than 100 localities now under study, mollusks are now reported from at least 14 localities from the Lameta Formation (Kl) (infratrappean) and 15 localities from the first three Deccan intertrappean (KDi) intervals in the states of Maharashtra (Chandrapur [Kl, KDi], Nagpur [KDi], Wardha [KDi], and Yavatmal [KDi] Districts) and Madhya Pradesh (Jabalpur [Kl], Sagar [Kl], and Chhindwara [KDi] Districts). Mollusks from two localities are now reported from an unnamed infratrappean unit and at multiple horizons from two localities from the Ir-bearing third intertrappean interval in the state of Gujarat (Kutch District [Kinf, KDi]). A main study area is along the eastern outcrop edge of the Deccan Traps in the Nand-Dongargaon Basin, where specimens are found in coarse and fine clastic sediments and commonly preserved as carbonate and chert steinkerns or external molds. Lacustrine paleoenvironments predominate all sections, but these conditions are variable, with marlstone beds varying in both clastic and faunal content. Channel deposits are rare, but still fossiliferous. Intertrappean molluscan-bearing sections average about 2 m, but vary in their fossil content and preservation based on local paleoenvironmental conditions and may covary in abundance with ostracodes. The K/P boundary has been preliminarily correlated in the above study area to be above all of the known molluscan occurrences. Only one intertrappean Paleocene molluscan locality (state of Uttar Pradesh) is presently known. The initial production of basalt lavas seems to have had little effect on the distribution and abundance of nonmarine mollusks existing in isolated intertrappean environments. The apparent lack of a fossil record interpreted just before (~350 Ka) the K/P boundary is part of ongoing investigations. Over 50 mollusk-bearing localities have yet to be assigned an intertrappean interval and many more mapped (Geological Survey of India) fossil localities have yet to be documented for their content or level. These records may permit further biostratigraphic organization and interpretation of the India end-Cretaceous extinction and survivorship record.

2006 Philadelphia Annual Meeting (22–25 October 2006)
General Information for this Meeting
Session No. 182
Paleontology/Paleobotany IX: Fossil Distributions in Time and Space
Pennsylvania Convention Center: 112 A
8:00 AM-12:00 PM, Wednesday, 25 October 2006

Geological Society of America Abstracts with Programs, Vol. 38, No. 7, p. 443

© Copyright 2006 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.