Phanerozoic Cycles of Sea-Level Change from Indian Plate: From Overview with a Base Chart
D. S. N. Raju
Univ of Utah, EGI Salklate City, Dehradun, India
An effort has been made to synthesize the basic and interpreted data on cyclicity of sea level changes. Chart of Phanerozoic cycles of sea-level changes on Indian plate is presented.
Neoproterozoic - Cambrian: Myrow et al. (2006) recognized 40 fourth order cycles from lower to middle Cambrian of Spiti. Ordovician- Devonian: In Sptiti-Zanskar region there is record of fluctuations in sea-level.Carboniferous: Several phases of transgressions and regressions.Permian: Two marine transgressions are recognized.Triassic: Garzanti et al., (1995) recognised eleven 3rd / 4th order cycles in the mid Carnian to mid Norian succession at Muth, Spiti Valley.Jurassic : Based on detailed synthesis, Jai Krishna (2005) identified 29 third order sequences / cycles in Kutch in a span of ~26 My from Bajocian to Tithonian.Cretaceous: Six T/R cycles in the span of Albian to Maastrichtian.Paleocene: One of the major MFSs in the Indian basins is during zones P4 / P5.Early Eocene: About 6 low amplitude cycles are recognisable in several basins of India.Middle Eocene: Major MFS in India is during zone P13.Late Eocene: Major regression of sea is recorded from several basins of India. However, deep water conditions prevailed in a few basins. In Cauvery Basin two cycles are recognizable.Oligocene: 7 + 1 (?) cycles / parasequences are recognizable in the Oligocene outcrop area of Kutch.Early Miocene: Six and half 3rd order cycles are recognized on the basis of foraminifera in KG Basin.Middle Miocene: In exposed succession of Kutch 5 MFSs are recognizable.
Christie - Blick et al., (2007) endorse continued research in quantifying the timing and the amplitude of sea-level change (with specified uncertainties) particularly for the Cenozoic and integrating passive margin backstripping in a sequence startigraphic context with the much higher resolution deep sea oxygen isotope record.
Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery