Geological еvents at the Cretaceous – Paleogene boundary in Georgia (Caucasus)

Pages: 
pp. 35-43
Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 117334 Moscow
State University of Tbilisi, 380009 Tbilisi, Georgia
Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
Caucasian Institute of Mineral Resources, 380062 Tbilisi, Georgia
Abstract: 

A continuous section at Tetrickaro (South Georgia) of Maastrichtian-Danian shallow-marine paleontologically proved carbonate deposits is being described. Within the section, a boundary clay layer, 15 - 20 cm thick, has been established with anomalously high content of Ir (3.46-5.34 ng/g), with shock-quartz grains and reversed polarity corresponding to R-29 zone of the International Paleomagnetic Scale. Mass extinction of representatives of numerous marine macro- and micro-fossil groups has been established at the Maastrichtian-Danian boundary in Georgia. 18 species of inocerams, 16 species from 9 genera of ammonitids, 5 species of bellemnitids, 25 species from 12 genera of echinoidea, 6 species from 3 genera of orbitoids, 9 species from 3 genera of planktonic foraminifers and 60 species from 29 genera of calcareous nannoplankton have disappeared at the end of Maastrichtian.

Ш. Адамия, Н. Салуквадзе, М. Назаров, Г. Гонгадзе, Т. Гавадзе, Э. Киласония, Б. Асанидзе. Геологические события на границе мел-палеогена Грузии (Кавказ). В непрерывном разрезе мелкоморских карбонатных отложений Тетрицкаро (Южная Грузия), между палеонтологически хорошо датированными отложениями маастрихта и дания обнаружена пограничная глина (мощность 15—20 cm) с аномально высоким содержанием Ir (3,46—5,34 нг/г), зернами ударно-метаморфическо кварца, намагниченная обратно и соответствующая очевидно R-29 Международной палеомагнитной шкалы. К границе маастрихт-даний приурочено массовое вымирание ископаемой макро- и микрофауны морских бассейнов Грузии: 18 видов иноцерамов, 16 видов из 9 родов аммонитид, 5 видов беллемнитид, 25 видов из 12 родов ехиноидей, о видов из трех родов орбитоид, 9 видов из 4 рода планктонных фораминифер и 60 видов из 29 родов нанно-планктона.

VOLUME 23 (3)/June 1993

Scientific Institute of Mineral Resources 23, Sitnyakovo Blvd, 1505 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Committee of Geology and Mineral Resources, 22, Maria-Louisa Blud, 1000 Sofia, Bulgaria

Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
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Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
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Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 117334 Moscow
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State University of Tbilisi, 380009 Tbilisi, Georgia
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Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
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Geological Institute, Georgian Academy of Sciences, 380093 Tbilisi, Georgia
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Caucasian Institute of Mineral Resources, 380062 Tbilisi, Georgia

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Research Institute for Mineral Deposits, 1505 Sofia (now - Geology and Geophysics Limited)
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria