Lime muds and their genesis off-Northwestern India during the late Quaternary

Abstract

Two sediment types were found in five gravity cores collected from water depths between 56 m and 121 m along the northwestern continental margin of India: lime muds were abundant in the lower section while siliciclastic sediments dominated the upper section. Lime mud-dominated sediments in shelf cores contained 60%-75% carbonate, 0.3%-0.6% Sr and terrigenous minerals, whereas those at the shelf break were found to have >90% carbonate, 0.6%-0.8% Sr and traces of terrigenous minerals. Aragonite needles showing blunt edges, jointed needles and needles wrapped in smooth aragonite cement were found to be common. Stable (O and C) isotopes of lime mud indicate a potentially freshwater contribution for shelf cores and purely marine contribution for those at the shelf break. Calibrated radiocarbon ages of the lime muds ranged from 17.6-11.9 ka in different cores. The results reported here suggest that the lime muds in the shallow shelf are probably reworked from the Gulf of Kachchh, whereas those at the shelf break were biodetrital, initially formed on the carbonate platform during low stands of sea level and then exported. The change in lime mud-dominated to siliciclastic-dominated sediments in the cores may be due to climate change and rapid rise in sea level during the early Holocene.

Offshore high‐grade limemud resources of west coast of India: Economic potential and industrial applications

“…A similar scale of limemud occurrence is known from the carbonate platforms of Bahamas, Florida, and Belize as well as shallow water ramps of the Persian Gulf (Boardman & Carney, 1991; Cloud, 1962; DeGroot, 1965; Dix, 2001; Geyman et al, 2022; Ginsburg, 1956; Lowenstam & Epstein, 1957; Matthews, 1966; Milliman et al, 1993; Mitterer, 1972; Neuman & Land, 1975; Robbins & Blackwelder, 1992; SEPM, 2017; Steinen et al, 1988; Stockman et al, 1967; Taylor & Purkis, 2012; Wells & Illing, 1964). The majority of studies on offshore limemud focused on genesis or global carbonate budget estimation (Cloud, 1962; De Groot, 1965; Dix, 2001; Lowenstam & Epstein, 1957; Matthews, 1966; Milliman et al, 1993; Neuman & Land, 1975; Purnachandra Rao et al, 2012; Rees et al, 2007; Stockman et al, 1967; Wells & Illing, 1964). In contrast, few studies reported the industrial application of offshore carbonates.…”