TY - JOUR
T1 - Paleomagnetic and 40Ar/39Ar age constraints on the timing of deposition of deep-water carbonates of the Kurnool Group (Cuddapah basin) and correlation across Proterozoic Purana successions of Southern India
AU - Wabo, Hervé
AU - Beukes, Nicolas J.
AU - Patranabis-Deb, Sarbani
AU - Saha, Dilip
AU - Belyanin, Georgy
AU - Kramers, Jan
N1 - Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2022/1
Y1 - 2022/1
N2 - The sedimentary basins of the Bastar and Dharwar cratons, namely Chhattisgarh, Cuddapah, Intravati, Kaladgi-Bhima, and Pranhita-Godavari are located to the south of the Central Indian Tectonic Zone. These Southern Purana basins host well-preserved successions that may be divided into four unconformity-bounded sequences (i.e., Sequences I to IV). Sequence III contains unique deep-water carbonate layers, among which the Narji Limestone in the Cuddapah basin is representative. These carbonate layers have been shown to be of Mesoproterozoic age in most basins. However, the age of the Narji Limestone is still debated. Here, we report a primary paleomagnetic pole (26.2°N, 063.2°E, A95 = 13.7°) with a positive fold test from the Narji Limestone, and also a reset 40Ar/39Ar age of ∼800 Ma obtained on a glauconite. Our results, combined with existing paleomagnetic data indicate that the Narji Limestone and Sequence III carbonates of the other Southern Purana basins share a similar primary paleomagnetic signature. The paleomagnetic poles of these carbonates plot consistently, and are used to calculate a mean pole (36.3°N, 070.8°E, A95 = 10.7°) that compares well with a ∼1.19 Ga Indian pole. Our results contradict the view that Sequence III carbonates of the individual Southern Purana basins were deposited at different times as previously inferred from geochronological data. Instead, we suggest that these carbonates represent interconnected successions deposited in middle to late Mesoproterozoic times during an extensive marine flooding event on the Southern India craton. Our results support the suggestion that the existing Neoproterozoic ages for Sequence III may reflect post-depositional events.
AB - The sedimentary basins of the Bastar and Dharwar cratons, namely Chhattisgarh, Cuddapah, Intravati, Kaladgi-Bhima, and Pranhita-Godavari are located to the south of the Central Indian Tectonic Zone. These Southern Purana basins host well-preserved successions that may be divided into four unconformity-bounded sequences (i.e., Sequences I to IV). Sequence III contains unique deep-water carbonate layers, among which the Narji Limestone in the Cuddapah basin is representative. These carbonate layers have been shown to be of Mesoproterozoic age in most basins. However, the age of the Narji Limestone is still debated. Here, we report a primary paleomagnetic pole (26.2°N, 063.2°E, A95 = 13.7°) with a positive fold test from the Narji Limestone, and also a reset 40Ar/39Ar age of ∼800 Ma obtained on a glauconite. Our results, combined with existing paleomagnetic data indicate that the Narji Limestone and Sequence III carbonates of the other Southern Purana basins share a similar primary paleomagnetic signature. The paleomagnetic poles of these carbonates plot consistently, and are used to calculate a mean pole (36.3°N, 070.8°E, A95 = 10.7°) that compares well with a ∼1.19 Ga Indian pole. Our results contradict the view that Sequence III carbonates of the individual Southern Purana basins were deposited at different times as previously inferred from geochronological data. Instead, we suggest that these carbonates represent interconnected successions deposited in middle to late Mesoproterozoic times during an extensive marine flooding event on the Southern India craton. Our results support the suggestion that the existing Neoproterozoic ages for Sequence III may reflect post-depositional events.
KW - Ar/Ar geochronology
KW - Deep-water carbonate
KW - Narji Limestone
KW - Paleomagnetism
KW - Southern Purana basins
UR - http://www.scopus.com/inward/record.url?scp=85117881156&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2021.104984
DO - 10.1016/j.jseaes.2021.104984
M3 - Article
AN - SCOPUS:85117881156
SN - 1367-9120
VL - 223
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
M1 - 104984
ER -