Title of article
Late Jurassic age for the Morokweng impact structure, southern Africa
Author/Authors
Hart، نويسنده , , Rodger J. and Andreoli، نويسنده , , Marco A.G. and Tredoux، نويسنده , , Marian and Moser، نويسنده , , Desmond and Ashwal، نويسنده , , Lewis D. and Eide، نويسنده , , Elizabeth A. and Webb، نويسنده , , Susan J. and Brandt، نويسنده , , Dion، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 1997
Pages
11
From page
25
To page
35
Abstract
A roughly 70 km diameter circular feature buried beneath the Kalahari sands in South Africa is revealed on regional aeromagnetic maps. Boreholes drilled into the centre of the structure intercept a ∼ 250 m thick sheet of quartz norite, interpreted as an impact melt, which overlies brecciated and shock metamorphosed basement granite. Zircons recovered from the quartz norite, yield U-Pb ages of 145 ± 0.8 Ma, and biotites provide Ar-Ar ages of 144 ± 4 Ma. These data provide strong evidence for the occurrence of a Late Jurassic impact crater (the Morokweng impact structure) ∼ 100 m beneath the surface.
Keywords
geochemistry , impact craters , Ar/Ar , Absolute age , U/Pb , Kalahari desert
Journal title
Earth and Planetary Science Letters
Serial Year
1997
Journal title
Earth and Planetary Science Letters
Record number
2320370
Link To Document