The Lithosphere Beneath the Indian Shield: A Geodynamic Perspective

ISBN-13: 9783030529444 / Angielski / Miękka / 2021 / 280 str.

Ashoka G. Dessai

Opis

This book explores the geotectonic evolution of the lithosphere beneath the Indian Shield, which comprises a collage of cratons variously bounded by mobile belts and palaeo-rifts. The lithosphere beneath these is fairly thin compared to other cratons worldwide, petrologically varied and shows considerable variation in thickness with depth both intra-craton and among cratons. Moreover, it has been subjected to the influence of repeated magmatic episodes from Proterozoic to Palaeocene, which have variously impacted different parts of the shield. The thermotectonic influence on constituent cratons is variable depending on the evolutionary history. This book discusses the impact of successive tectonomagmatic events on the evolution of the deep crust and shallow mantle, and their Phanerozoic modification as gleaned through the xenolith window.The book provides a petrotectonic perspective on the deep crust and shallow mantle from direct samples brought up as xenoliths of deep lithologies, and offers a comprehensive overview for students, researchers, academics and professionals, integrating the results of petrological studies of deep lithologies and geophysical investigations to (i) shed light on the physico-chemical and thermal structure of the lithosphere from an array of geotectonic settings and (ii) gain insights into the spatio-temporal  evolution of the Indian Shield. An in-depth guide critical thinking on the complex issue of mantle differentiation, magmatism, lithosphere modification and crustal growth over time, the book allows readers to gain a better understanding of the processes that affect the lithosphere and shape the crust on which we live.

Recenzje

"The narrative is simple, concise, well-researched, balanced, simple to peruse and comprehend, and offers a good account of the integration of various datasets ... . The book is well presented and comprises useful and appropriate tables and figures. It would serve as a basic text on Indian lithosphere and would provide an impetus for integrated studies in the continuing investigation of the evolution of the Indian shield and cratonic areas the world over." (Makarand G. Kale, Journal of the Geological Society of India, Vol. 97, July, 2021)

Spis treści

Chapter 1:  Continental lithosphere

Introduction

Studies in India

Methods and Techniques

Seismic Surveys

Electromagnetic and Magnetotelluric Techniques

Xenolith Studies

Relevance of Xenolith Studies

Limitations of Xenolith Studies

Thermal Structure of the Crust

Thermobarometry

Limitations

Heat Flow Studies

Heat Generation

 Mechanism of Heat Transfer

Heat Flow Measurements

Constraints

Reduced Heat Flow

Magnetic Studies

Curie Point Isotherm

Gravity Methods

Primary Geochemical Differentiation

Bimodality of the Crust

Continental Crust

Seismic Structure 

Types of Continental Crust

Shield

Craton

Platform

Oceanic Crust 

The Deep Crust

Inferences from Receiver Function Studies

Earth’s Mantle

Mantle Composition

Lithospheric Mantle: Seismic Structure

Petrologic Lithosphere 

Thermal Lithosphere

Chapter 2: Indian Shield

Introduction

Geotectonic Framework

Geology of  Peninsular Block

Aravalli Craton

Bundelkhand Craton

Singhbhum Craton

Bastar Craton

Dharwar Craton

Western Dharwar Craton

Eastern Dharwar Craton

Granulite Terrain

Chotanagpur Gneiss-Granulite Terrain   

Eastern Ghat Mobile Belt

Southern Granulite Terrain

Granulite Types in South India

Igneous vs Metasomatic Origin

Nilgiri Domain

Madurai Domain

Offshore Region: Western Margin

Eastern Margin Offshore

Geophysical Studies in South India

Crustal Structure from Magsat and Gravity Data

Seismic Structure of WDC

Structure of the Crust beneath EDC

Crust beneath Southern Granulite Terrain

Comparative Assessment of Indian Shield with Other Shields

Xenolith Host Rocks

CITZ Dyke Swarm

Western Continental Margin Dyke Swarm

Duration of Deccan Magmatism

Chapter 3: Petrology

Introduction

Xenolith Occurrences in India

       Radiometric Ages of  Host Rocks

Petrology of  Xenoliths

       Xenoliths from Deccan Traps (WDC)

                Mantle Xenolith: Lherzolites

                Crustal Xenoliths: Granulites

                Mineral Chemistry

                Xenoliths from Kutch (Aravalli Craton)

       Xenoliths in Kimberlites 

                Xenoliths from Bundelkhand Craton

                Lherzolite Xenoliths from EDC

                Eclogite Xenoliths from EDC

                Xenolith from Bastar Craton

                Dyke Boudins from Pericratonic Terrain

Chapter 4: Lithosphere structure

Introduction

Crustal Structure: Gravity and Seismic Studies

Bundelkhand Region North of CITZ

Northern Region of WDC

Central Region of WDC

Structure from S wave velocity Function

Eastern Region beneath EDC

Pericratonic Domain: Southern Granulite Terrain

Offshore Crust of Arabian Sea

Laxmi Ridge Section

Chagos-Maldive Ridge Section

Offshore Crust of Bay of Bengal

Nature of Sub-continental Moho

Characteristics of Shallow Mantle

Nature of Crust-Mantle Boundary

Seismic Interpretation

Chapter 5: Geothermal structure

Introduction

Thermal Structure of the Shield

Bundelkhand and WDC: Thermal structure

Thermal Regime of the EDC and Bastar Cratons

Southern Granulite Terrain: Thermal Characteristics

Xenolith vis-a-vis Heat Flow Geotherms

Comparison with Cratons Globally

Inferences from Geotherms in Other Cratons

Estimates of Thermal Boundary Layer

Thermal Evolution of South Indian Cratons

Thermal Peculiarities of the WDC 

Thermal Characteristice of EDC

Temporal Variation in Thermal Structure

Surface Heat Flow of the South Indian Shield

Heat Flow Variation among South Indian Cratons

Global Heat Flow Observations

Heat Flow along Craton Margins

Influence of Composition on Heat Generation

Thermal Equilibration over Time

Contribution to Heat Flow: Xenolith Guestimates

Inferences from Other Parts of the World

Thermal Perturbation: An Effect of Crustal Thickening

Causes of Excess Heat and Estimation of Crustal Accretion

Overall Heat Production of the Crust

Chapter 6: Integration of insights

Introduction

Crustal Structure Parameters  

Western Dharwar Craton: A Synthesis

Eastern Dharwar Craton 

Pericratonic Belt and Offshore Crust

Nature of Sub-continental Moho

Thermal Perspective: Indian Shield

Western Dharwar and Bundelkhand Cratons

Eastern Dharwar Craton and Pericratonic Region

Tectonomagmatic Accretions

Western Dharwar Craton

Composition of the Lower Crust: Xenolith Assessment

Inferences from Geophysical Estimates

Lower Crust of Eastern Dharwar Craton

Lower Crust of Pericratonic Terrain

Origin of the Lower Crustal Granulites

Exhumation of SGT

Evolution of  Lower Crust

Formation of  Felsic Crust: Recycling Mechanism

Nature and Composition of  the Lithospheric Mantle

Archaean vs Proterozoic Mantle

SCLM beneath Western India

SCLM beneath EDC

Metasomatic Modification of the Lithospheric Mantle   

Thickness of SCLM and its Evolution

Contribution of Continental Margin to Lithospheric Growth 

Offshore Evidences of de-roofing of Continental Lithosphere

       Crustal Growth Processes: A Synoptic Overview

Nature of Pristine Crust

Secular Changes in Crustal Composition

Generation of Primitive Crust

Greenstone Belts

Komatiites

Layered Complexes

Dyke Swarms

Anorthosite Complexes

Concluding Remarks

Selected bibliography

O autorze

Prof. Dr. Ashoka Dessai has over 39 years of teaching and research experience at post-graduate level, initially at S. P. Pune University, and later at Goa University. He has conducted research in India and abroad, published over 50 research papers in peer-reviewed national and international journals and has been a reviewer for international journals published by Springer and other publishers. 

Prof. Dr. Dessai has authored two books: (i) Geology and Mineral Resources of Goa, New Delhi Publishers, and (ii) Goa: Geology, Industry and Environment (in press), Publisher: Directorate of Art and Culture, Govt. of Goa. He has also delivered lectures at several universities and professional organisations and research institutes in India and abroad. 

He has worked in wide variety of terrains, such as ophiolites of Ladakh Himalaya, Precambrian layered complexes and komatiitic ultramafites of South India, Deccan Traps of western India, including Precambrian iron and manganese ores, chromites, and laterites and bauxites. He has participated in an Indian Ocean expedition for prospecting of polymetallic nodules. 

Prof. Dr. Dessai has served as the Dean of the Faculty of Pure Sciences and Registrar of Goa University.