Usur Gr
Period:
Tonian
Age Interval:
late Tonian
Province:
Proterozoic S.India Pranhita-Godavari east basin
Type Locality and Naming
Lithology and Thickness
Sandstone. Upward succession of Nambi Breccia Fm, Doli Sandstone Fm, and Usur Sandstone Fm
Lithology Pattern:
Coarse-grained sandstone
Relationships and Distribution
Lower contact
Unconformable onto Chalamala Sandstone Fm at top of Alabaka Gr. Development of 200-m-thick bouldery, breccia-conglomerate with gritty sandstone in the lower part of the Usur Group represent a new cycle of deposition over the Albaka Gr.
Upper contact
Unconformably overlain by Gondwana Supergroup (which begins with early Permian glacial Talchir Fm)
GeoJSON
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[79.28,20.07],[79.69,19.75],[81.77,16.74],[81.4,16.64],[79.6,19.08],[79.27,19.75],[79.28,20.07]]]]}}
Fossils
Age
Age Span:
Beginning stage:
Tonian
Fraction up in beginning stage:
0.7
Beginning date (Ma):
804.00
Ending stage:
Tonian
Fraction up in the ending stage:
0.9
Ending date (Ma):
748.00
Depositional setting
Deepening upward from basal alluvial fan to shallow coastal
Depositional pattern:
Additional Information
Compiler:
From: Saha D. (Dilip), Patranabis-Deb, S., and Colllins, A.S. (2016) Proterozoic stratigraphy of southern Indian cratons and global context. In: Stratigraphy & Timescales, 1: 1-59.