Ambota Fm
Period:
Mesoproterozoic
Age Interval:
early Calymmian
Province:
N.India Lesser Himalaya
Type Locality and Naming
Himachal Pradesh-Uttarakhand, Deoban Basin, named after Ambota village. [Original Publication: Ganesan, T.M., Verma, R.N. (1981) The Deoban structural belt of Garhwal Himalaya. Jour. Geol. Soc., India 22, 201-215]
Lithology and Thickness
Oolitic limestone, breccia, pink, purple, green limestone, stromatolitic limestone, dolostone, platy limestone with shale.
Lithology Pattern:
Limestone
Relationships and Distribution
Lower contact
Conformable with Bohar Fm.
Upper contact
Unconformable with Mandhali Fm.
Regional extent
Between the Tons and Jamuna valleys
GeoJSON
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Fossils
Stromatolites: Jurusania spp.
Age
The range 1600-1555 Ma is adopted here for the Deoban Gr (see that entry for details), and each component formation is given a 15 Myr span => 1570-1555 for this upper formation.
Age Span:
Beginning stage:
Calymmian
Fraction up in beginning stage:
0.15
Beginning date (Ma):
1,570.00
Ending stage:
Calymmian
Fraction up in the ending stage:
0.23
Ending date (Ma):
1,554.00
Depositional setting
Shallow marine
Depositional pattern:
Additional Information
Compiler:
O.N. Bhargava & Birendra Singh.