Course Title Sedimentology and Principles of Stratigraphy Course No EES 307
Learning Objectives:
Sedimentology is the study of sediments, particularly focusing on how it is produced, transported, and deposited. Stratigraphy, which is a synthesis of the stratal record, emphasizes the analysis of layered sequences, principally sedimentary, that cover about 3/4th of the Earth's surface. Sedimentary rocks illuminate many of the details of the Earth's history - effects of sea level change, global climate, tectonic processes, and geochemical cycles. This course will cover basics of fluid flow and sediment transport, sedimentary textures and structures, and provide an overview of facies analyses, modern and ancient depositional sedimentary environments, and the relationship of tectonics and sedimentation.
Course Contents:
Development of Concepts in Sedimentology: The context of sedimentology; Weathering, erosion, transportation; Sedimentation in the backdrop of the interaction of plate tectonics and hydrological cycle; Soil formation and sediment production, regolith, chemical index of alteration.
Textural Properties of Sediments and Sedimentary Rock: Grain Size and scale, grain size distributions; Porosity and permeability; Grain orientation and fabric.
Fluid Flow and Sediment Transport: Fluid gravity flows – Classification, velocity distribution in turbulent flows; Sediment transport under unidirectional flows, Hjulstrom’s diagram, Shield’s criterion; Bedforms and structures under unidirectional flow – Flow regime concept, bedform stability diagrams.
Primary Sedimentary Structures: Primary structures and their directional significance, bedding, cross-bedding – planar, trough, HCS, Herring bone, normal and inverse graded beds; Bedding plane markings, biogenic sedimentary structures - Stromatolites and Ichnofossils; Penecontemporaneous Deformation Sturctures (PCD).
Depositional Sedimentary Environments: Classification; methods and data integration for environmental reconstruction - vertical faces associations.
Facies: Walther’s Law of correlation of sedimentary facies, migration of facies tracts; Facies models and interpretation of depositional environments – Examples from continental, transitional and marine depositional environments. Terrigenous Clastic Sediments: Sediment connectivity and transport systems, conglomerates, breccia, sandstone, compositional versus textural maturity of sediments; Sedimentology of mudstones.
Carbonate Rocks: Importance of limestone, carbonate continuum and carbonate minerals, carbonate geochemistry, controls on carbonate deposition; Carbonate sediment factories, bio- and organo-mineralisation, warm and cool water carbonates, pelagic carbonates, reefs and build-ups; Carbonate diagenesis.
Biogenic Sedimentary Rocks: Chert and siliceous sediment, phosphates, and organic-rich sediments; Chemical and non-epiclastic sedimentary rocks – Iron-rich sedimentary rocks and evaporates; Volcanoclastic sedimentary rocks – fragmentation, eruption column characteristics non-genetic classification of pyroclastic rocks.
Siliciclastic Diagenesis: Compaction and cementation; Authigenesis, recrystallization and replacement; Diagenesis and porosity.
Tectonics of Sedimentary Basins: Basin classification – intraplate (pre- and post- rift), Divergent and convergent – margin basins, collision and post – collision basins, strike–slip basins; mechanisms of basin formation; The uniform stretching model.
Concepts in Lithostratigraphy and Biostratigraphy: Index fossils, FAD/LAD, bio stratigraphic zonation and correlation, time significance of biostratigraphic events; Geophysical and chemostratigraphic correlation - well logging, seismic stratigraphy, chemostratigraphy.
Magnetostratigraphy and Geochronology: Principles of magnetostratigraphy and development of GPTS (Global Polarity Time Scale), Geochronological techniques as applied to the Quaternary record (Carbon-14, luminescence, amino- acid dating and Oxygen isotope stratigraphy) and pre- Quaternary (Ar-Ar), U-Pb, fission track dating.