Anisotropy of magnetic susceptibility (AMS) studies of Campanian–Maastrichtian sediments of Ariyalur Group, Cauvery Basin, Tamil Nadu, India: An appraisal to Paleocurrent directions

• Published in: Journal of Earth System Science Vol. 123; no. 2; pp. 351 - 364
• Main Authors: PAPANNA, G, VENKATESHWARLU, M, PERIASAMY, V, NAGENDRA, R
• Format: Journal Article
• Language: English
• Published: India Springer India 01.03.2014; Springer Nature B.V
• Subjects: Anisotropy; Basins; Biotite; Cretaceous; Direction; Distribution; Earth and Environmental Science; Earth Sciences; Fabrics; Formations; Limestone; Magnetic fields; Magnetic permeability; Magnetic susceptibility; Marine; Palaeocurrents; Parameters; Sandstone; Sediment; Sediment samples; Sedimentary rocks; Sediments; Shape; Shape factor; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Susceptibility; Tamil Nadu India; India; India, Tamil Nadu; ISW, India, Tamil Nadu, Cauvery Basin; Cauvery basin; paleocurrent direction; magnetic fabric; AMS
• ISSN: 0253-4126; 0973-774X
• DOI: 10.1007/s12040-013-0400-1

Oriented samples of sediments from Ariyalur Group, Cauvery Basin, south India, were studied for low field anisotropy of magnetic susceptibility (AMS) measurements to unravel the magnetic fabrics and paleocurrent directions. The results of AMS parameters of the sediments indicate primary depositional fabrics for Sillakkudi, Ottakovil and Kallamedu sandstone formations and secondary fabric for Kallankurichchi limestone formation. The obtained low degree of anisotropy ( P j ), oblate shape AMS ellipsoid and distribution of maximum ( K 1 ) and minimum ( K 3 ) susceptibility axes on equal area projection confirm the primary sedimentary fabric for Sillakkudi, Ottakovil and Kallamedu Formations. In the case of ferruginous, lower arenaceous, Gryphaea limestone and upper arenaceous limestone beds of Kallankurichchi Formation have recorded more than one fabric. The observed AMS parameters like shape factor ( T ) (prolate to oblate), q value and random distribution of minimum ( K 3 ) and maximum ( K 1 ) susceptibility axes are supported for secondary fabrics in Kallankurichchi Formation as a result of post-depositional processes. Based on petrographic studies, it can be established that K 1 AMS axis of biotite mineral could represent the flow direction. The established paleocurrent direction for Sillakkudi is NW–SE direction while Ottakovil and Kallamedu Formations recorded NE–SW direction. Overall the paleoflow directions observed for Ariyalur Group is NE–SW to NW–SE.