Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten wate...Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation.Watersheds 7-9 to the north(N)are tectonically active,which can be linked with the North Kathiawar Fault System(NKFS)and followed by watersheds 6,10,1,4 and 5.Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6-9.Higher R^(2)values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others.The R^(2)curve fitting model and earthquake magnitude/depth analysis confirm the region to be active.The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.展开更多
Across the Himalayan foreland area,alluvial fans respond to fluvial depositional landforms created by active tectonics and are incorporated within hydro-sediment processes.Each tributary of the master stream has its w...Across the Himalayan foreland area,alluvial fans respond to fluvial depositional landforms created by active tectonics and are incorporated within hydro-sediment processes.Each tributary of the master stream has its water and sediment to discharge,which assists in initiating several mesolevel fans in response to the active tectonics in Jaldhaka basin.Along the mountain front,active MBT(Main Boundary Thrust),MFT(Main Frontal Thrust)and lineaments(parallel and transverse to Himalaya)have governed the tectonically active Quaternary foreland area where numerous meso-level fans have developed.The study aims to estimate the tectonic activeness of each meso-fan using the morphotectonic indicators.The tributaries of the Jaldhaka River are permuted to the recent tectonism or neotectonics to form each meso fan with its basin displaying the varying degree of their activeness and aggradation system.Statistical methods like technique for order performance by similarity to ideal solution(TOPSIS)and VIKOR(Vlse Kriterijumska Optimizacija Kompromisno Resenje)that specify multicriteria optimization and compromise solution,in Serbian have ranked the Fan 2 as mostly active and Fan 4 is comparatively tectonically stable.The hydro-sediment characteristics reveal the topographic spatial dynamics of Fan 4 where lobe 3 has elevated from 1984-2014.The XRD analysis specifies the scientific key in response to the dominance of dolomite in the aggraded elevated bed sediments carried by the Rohtikhola River.The conceptual fan models of Fan 2and 4 display the fan development phases through four stages.It has clearly defined the extension of the fan lobes of Fan 2 and 4.It is summarized that within a common climatic zone and similar neo-tectonic setting,meso-level fans have differential morphotectonic signatures with dynamic aggradation processes.展开更多
The Gulf of Mannar has been producing natural gas in the Sri Lankan portion.This indicates that a detail geoscientific study is to be undertaken from the Indian section of the gulf,which can have a far-reaching implic...The Gulf of Mannar has been producing natural gas in the Sri Lankan portion.This indicates that a detail geoscientific study is to be undertaken from the Indian section of the gulf,which can have a far-reaching implication in the Indian petroleum geoscience.In this work,morphometric and gravity studies were made from the gulf/basin near the onshore area,and bathymetric studies from the offshore portion of the Mannar basin within the Indian sector.Five watersheds were delineated based on study of eight geomorphic parameters on remote sensing images form the onshore area.Out of these watersheds 4 and5 are found to be presently tectonically most active.Well-bore stability issue is to be considered while drilling these portions in future.We further prepared a regional contour map for the offshore study area,analysed the free air gravity data from the onshore area,and deduced the First Vertical Derivative(FVD)and Tilt Derivative Ratio(TDR).Bathymetric height gradually increases along the north-south trend from the coast region of the study area towards the central region,while the gravity magnitudes display a very sharp gradient(around 150 mGal).The gravity anomaly shows positive values at continental shelf(0-160 mGal),which includes parts of watersheds 1 and 3 and attains negative magnitude(up to-20mGal)towards the basin area.Negative gravity anomaly in the offshore area may indicate presence of hydrocarbon but more studies are needed for confirmation.Apparently,almost a negative correlation(except watershed 1)between surface elevation and free air gravity magnitudes has been found.展开更多
基金Research Development Fund(IIT Bombay)supported SM。
文摘Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation.Watersheds 7-9 to the north(N)are tectonically active,which can be linked with the North Kathiawar Fault System(NKFS)and followed by watersheds 6,10,1,4 and 5.Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6-9.Higher R^(2)values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others.The R^(2)curve fitting model and earthquake magnitude/depth analysis confirm the region to be active.The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.
文摘Across the Himalayan foreland area,alluvial fans respond to fluvial depositional landforms created by active tectonics and are incorporated within hydro-sediment processes.Each tributary of the master stream has its water and sediment to discharge,which assists in initiating several mesolevel fans in response to the active tectonics in Jaldhaka basin.Along the mountain front,active MBT(Main Boundary Thrust),MFT(Main Frontal Thrust)and lineaments(parallel and transverse to Himalaya)have governed the tectonically active Quaternary foreland area where numerous meso-level fans have developed.The study aims to estimate the tectonic activeness of each meso-fan using the morphotectonic indicators.The tributaries of the Jaldhaka River are permuted to the recent tectonism or neotectonics to form each meso fan with its basin displaying the varying degree of their activeness and aggradation system.Statistical methods like technique for order performance by similarity to ideal solution(TOPSIS)and VIKOR(Vlse Kriterijumska Optimizacija Kompromisno Resenje)that specify multicriteria optimization and compromise solution,in Serbian have ranked the Fan 2 as mostly active and Fan 4 is comparatively tectonically stable.The hydro-sediment characteristics reveal the topographic spatial dynamics of Fan 4 where lobe 3 has elevated from 1984-2014.The XRD analysis specifies the scientific key in response to the dominance of dolomite in the aggraded elevated bed sediments carried by the Rohtikhola River.The conceptual fan models of Fan 2and 4 display the fan development phases through four stages.It has clearly defined the extension of the fan lobes of Fan 2 and 4.It is summarized that within a common climatic zone and similar neo-tectonic setting,meso-level fans have differential morphotectonic signatures with dynamic aggradation processes.
文摘The Gulf of Mannar has been producing natural gas in the Sri Lankan portion.This indicates that a detail geoscientific study is to be undertaken from the Indian section of the gulf,which can have a far-reaching implication in the Indian petroleum geoscience.In this work,morphometric and gravity studies were made from the gulf/basin near the onshore area,and bathymetric studies from the offshore portion of the Mannar basin within the Indian sector.Five watersheds were delineated based on study of eight geomorphic parameters on remote sensing images form the onshore area.Out of these watersheds 4 and5 are found to be presently tectonically most active.Well-bore stability issue is to be considered while drilling these portions in future.We further prepared a regional contour map for the offshore study area,analysed the free air gravity data from the onshore area,and deduced the First Vertical Derivative(FVD)and Tilt Derivative Ratio(TDR).Bathymetric height gradually increases along the north-south trend from the coast region of the study area towards the central region,while the gravity magnitudes display a very sharp gradient(around 150 mGal).The gravity anomaly shows positive values at continental shelf(0-160 mGal),which includes parts of watersheds 1 and 3 and attains negative magnitude(up to-20mGal)towards the basin area.Negative gravity anomaly in the offshore area may indicate presence of hydrocarbon but more studies are needed for confirmation.Apparently,almost a negative correlation(except watershed 1)between surface elevation and free air gravity magnitudes has been found.
