Neogene-Quaternary Sequence in Gujarat: A Review

Abstract

Abstract The constituent rocks of Neogene are conglomerates, grits, silty sandstones, marls and argillaceous limestones. Marine Quaternaries are represented by the miliolite rocks of Saurashtra (Middle Pleistocene) and younger Holocene Rann sediments, mudflats and beach rocks. The transition of Neogene to Quaternary is not fully understood. Perhaps regressive conditions prevailed during the close of Pliocene and in the early Pleistocene. Evidences point to a bw strandline during the Lower Pleistocene. The Quaternary period is marked by two major transgressions-one in Ihe Middle Pleistocene and the other at the advent of Holocene. The Middle Pleistocene transgression gave rise to the miliolites, whereas the Holocene marine deposits are related to the last post glacial transgression. The Neogene-Quaternary sequence requires further examination, particularly the so-called Pliocene, Plio-Pleistocene and Lower Pleistocene rocks. As the N-Q sea levels were related to climatic changes, a close scrutiny of the onshore continental record just above the marine Neogene rocks might provide some information towards fixing the nature of transition of Neogene to Quaternary. It would be essential to apply alternative criteria such as palaecmagnetic and therrnoluminiscence measurements and radicmetric age determinations for obtaining a clearer picture.