Depositional and post-depositional setting of Maastrichtian limestone, Ariyalur Group, Cauvery Basin, South India:a geochemical appraisal
MetadataShow full item record
Major, trace, REE, and stable isotopic composition of Maastrichtian limestones of Cauvery Basin were studied to decipher their depositional and post-depositional environment. The major oxides and trace elements concentration of these limestones were normalized using Post-Archean Australian Shale (PAAS) values. The concentration of CaO is having a significant enrichment, and MgO, K2O, Co, Ni, Cu, Zn, Pb, Ba, U, and Th are moderately depleted, whereas Sr and Na2O contents are relatively similar to the PAAS values. The PAAS-normalized REE + Y pattern of Maastrichtian limestones display relatively uniform pattern among the compositionally different limestones: (1) enriched LREE (average NdSN/YbSN = 5.03 ± 0.92); (2) positive Ce anomaly (average 1.79 ± 0.16); (3) negative GdSN/Gd* anomaly (average 0.52 ± 0.02); (4) low Y/Ho ratio (average Y/Ho = 0.14 ± 0.01). The average ΣREE contents in ferruginous, arenaceous, and biostromal limestones are 65, 64, and 52 ppm, respectively, which indicate that the mineralogical variation plays a major role in incorporation of ΣREE. The Kallankurichchi limestones have δ13C values range from −3.2 to −1.1‰PDB, and the δ18O values range between −7.8 and −5.5‰PDB. The negative δ13C and δ18O values and a moderate co-variation between δ13C and δ18O (r 2 = 0.35) indicate that the alteration of original isotopic composition is due to diagenesis.The positive Ce/Ce* confirms the clastic input into the system, and negative Mn* values and Th/U ratios (~0.29–1.4) in these limestones indicate their association with precipitation of carbonates in reducing (anoxic–dysoxic: Th/U ≤ 2) conditions.
Showing items related by title, author, creator and subject.
A Geochemical Proxy for Recognizing Sequence Stratigraphic Surfaces in Late Cretaceous Sediments of Ariyalur Area, Cauvery Basin, South IndiaNagendra, R.; Bakkiaraj, D.; Nagarajan, Ramasamy; Reddy, A. (2010)The geochemical tool is employed to recognize the sequence stratigraphic surfaces of the Campanian-Maastrichtian sediments of the Ariyalur area in the Cauvery Basin. The Sillakkudi Formation (Campanian) underlies the ...
Bastos de Paula, Osni (2011)This thesis is a multi-scale study of carbonate rocks, from the nanoscale and digital rock investigations to the imaging studies of carbonate reservoir analogues. The essential links between these extremes are the carbonate ...
Carbon, oxygen, and strontium isotope geochemistry of the Proterozoic carbonate rocks, Bhima basin, south India: Implication for diagenesisNagarajan, Ramasamy; Armstrong-Altrin, John; Sial, Alcides; Nagendra, Raghavendra; Ellam, Rob (2013)A carbonate dominated shallow marine Proterozoic Bhima basin consists of carbonates and clastic rocks, and is widely distributed in the northern part of the Karnataka state, south India. Limestones of the Shahabad Formation ...