scholarly journals Discovery of Deccan Inclination Anomaly and its possible geodynamic implications over the Indian Plate

2021 ◽  
Author(s):  
Satish Sangode ◽  
Ashish Dongre ◽  
Amarjeet Bhagat ◽  
Dhananjay Meshram
Keyword(s):  
Indian Ocean ◽  
Lava Flow ◽  
Sea Level ◽  
Evolutionary Model ◽  
Indian Plate ◽  
Deccan Volcanism ◽  
Geological Evidence ◽  
Palaeomagnetic Data ◽  
Reunion Plume ◽  
Spreading Rates

The rapid northward drift of the Indian plate during Deccan volcanism assumes a gradual shallowing of paleomagnetic inclinations in subsequent lava flow formations. A comparison of palaeomagnetic data produced during the last six decades reveals an inclination anomaly during Chron C29r (66.398 - 65.688 Ma) along with brief clockwise-counter-clockwise rotations during and after the main phase Deccan eruption. This interval temporally coincides with i) an accelerated Indian ocean spreading rates, ii) brief incursion of an inland ‘seaway’ and iii) a major drop in the sea level at the southern tip of the Indian Peninsula. Furthermore, the restoration of tilt later during C29n agrees with the withdrawal of the inland seaway and the development of a regional southward dip of the Deccan lava flow formations. Here, we produce an evolutionary model to postulate the interaction of the Réunion plume with the Indian lithospheric plate with coincident geological evidence demanding further exploration.

scholarly journals Discovery of Deccan Inclination Anomaly and its possible geodynamic implications over the Indian Plate

2021 ◽  
Author(s):  
S J Sangode ◽  
Ashish Dongre ◽  
Amarjeet Bhagat ◽  
Dhananjay Meshram
Keyword(s):  
Indian Ocean ◽  
Lava Flow ◽  
Sea Level ◽  
Evolutionary Model ◽  
Indian Plate ◽  
Deccan Volcanism ◽  
Indian Peninsula ◽  
Palaeomagnetic Data ◽  
Reunion Plume ◽  
Spreading Rates

Abstract The rapid northward drift of the Indian plate during Deccan volcanism assumes a gradual shallowing of paleomagnetic inclinations in subsequent lava flow formations. A comparison of palaeomagnetic data produced during the last six decades reveals an inclination anomaly during Chron C29r (66.398–65.688 Ma) along with brief clockwise-counter-clockwise rotations during and after the main phase Deccan eruption. This interval temporally coincides with i) an accelerated Indian ocean spreading rates, ii) brief incursion of an inland ‘seaway’ and iii) a major drop in the sea level at the southern tip of the Indian Peninsula. Furthermore, the restoration of tilt later during C29n agrees with the withdrawal of the inland seaway and the development of a regional southward dip of the Deccan lava flow formations. Here, we produce an evolutionary model to postulate the interaction of the Réunion plume with the Indian lithospheric plate with coincident geological evidences demanding further exploration.

scholarly journals The convergence history of India-Eurasia records multiple subduction dynamics processes

2020 ◽  
Vol 6 (19) ◽  
pp. eaaz8681 ◽  
Author(s):  
Adina E. Pusok ◽  
Dave R. Stegman
Keyword(s):  
Indian Ocean ◽  
Numerical Models ◽  
Plate Motion ◽  
Indian Plate ◽  
Geological Evidence ◽  
Sequence Of Events ◽  
History Of ◽  
The Indian Ocean ◽  
Fast Motion ◽  
Subduction System

During the Cretaceous, the Indian plate moved towards Eurasia at the fastest rates ever recorded. The details of this journey are preserved in the Indian Ocean seafloor, which document two distinct pulses of fast motion, separated by a noticeable slowdown. The nature of this rapid acceleration, followed by a rapid slowdown and then succeeded by a second speedup, is puzzling to explain. Using an extensive observation dataset and numerical models of subduction, we show that the arrival of the Reunion mantle plume started a sequence of events that can explain this history of plate motion. The forces applied by the plume initiate an intra-oceanic subduction zone, which eventually adds enough additional force to drive the plates at the anomalously fast speeds. The two-stage closure of a double subduction system, including accretion of an island arc at 50 million years ago, may help reconcile geological evidence for a protracted India-Eurasia collision.

Assessment of mass-induced sea level variability in the Tropical Indian Ocean based on GRACE and altimeter observations

2021 ◽  
Vol 95 (2) ◽  
Author(s):  
Shiva Shankar Manche ◽  
Rabindra K. Nayak ◽  
Prakash Chandra Mohanty ◽  
M. V. R. Shesasai ◽  
V. K. Dadhwal
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Tropical Indian Ocean ◽  
Sea Level Variability

Consequences of sea level and climate changes on the morphodynamics of a tropical coastal lagoon during Holocene: An evolutionary model

2014 ◽  
Vol 333 ◽  
pp. 156-172 ◽  
Author(s):  
D. Padmalal ◽  
K.P.N. Kumaran ◽  
K.M. Nair ◽  
Ruta B. Limaye ◽  
S. Vishnu Mohan ◽  
...  
Keyword(s):  
Sea Level ◽  
Coastal Lagoon ◽  
Climate Changes ◽  
Evolutionary Model ◽  
Tropical Coastal Lagoon

Impact of Satellite Altimetry on Simulations of Sea Level Variability by an Indian Ocean Model

2001 ◽  
Vol 24 (1) ◽  
pp. 53-63 ◽  
Author(s):  
S. K. Singh ◽  
Sujit Basu ◽  
Raj Kumar ◽  
Vijay K. Agarwal
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Ocean Model ◽  
Sea Level Variability

Intraseasonal-to-Interannual Variability of South Indian Ocean Sea Level and Thermocline: Remote versus Local Forcing

2012 ◽  
Vol 42 (4) ◽  
pp. 602-627 ◽  
Author(s):  
Laurie L. Trenary ◽  
Weiqing Han
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Sea Level ◽  
Time Scales ◽  
Ekman Pumping ◽  
Remote Forcing ◽  
South Indian ◽  
The Pacific ◽  
The Indian Ocean ◽  
Thermocline Variability

Abstract The relative importance of local versus remote forcing on intraseasonal-to-interannual sea level and thermocline variability of the tropical south Indian Ocean (SIO) is systematically examined by performing a suite of controlled experiments using an ocean general circulation model and a linear ocean model. Particular emphasis is placed on the thermocline ridge of the Indian Ocean (TRIO; 5°–12°S, 50°–80°E). On interannual and seasonal time scales, sea level and thermocline variability within the TRIO region is primarily forced by winds over the Indian Ocean. Interannual variability is largely caused by westward propagating Rossby waves forced by Ekman pumping velocities east of the region. Seasonally, thermocline variability over the TRIO region is induced by a combination of local Ekman pumping and Rossby waves generated by winds from the east. Adjustment of the tropical SIO at both time scales generally follows linear theory and is captured by the first two baroclinic modes. Remote forcing from the Pacific via the oceanic bridge has significant influence on seasonal and interannual thermocline variability in the east basin of the SIO and weak impact on the TRIO region. On intraseasonal time scales, strong sea level and thermocline variability is found in the southeast tropical Indian Ocean, and it primarily arises from oceanic instabilities. In the TRIO region, intraseasonal sea level is relatively weak and results from Indian Ocean wind forcing. Forcing over the Pacific is the major cause for interannual variability of the Indonesian Throughflow (ITF) transport, whereas forcing over the Indian Ocean plays a larger role in determining seasonal and intraseasonal ITF variability.

The Origin of Modern Atolls: Challenging Darwin's Deeply Ingrained Theory

2021 ◽  
Vol 13 (1) ◽  
pp. 537-573 ◽  
Author(s):  
André W. Droxler ◽  
Stéphan J. Jorry
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Direct Interaction ◽  
Evolutionary Model ◽  
Reef Growth ◽  
Sea Level Fluctuations ◽  
Fringing Reefs ◽  
Volcanic Islands ◽  
Karst Model ◽  
The Tropical Pacific

In 1842, Darwin identified three types of reefs: fringing reefs, which are directly attached to volcanic islands; barrier reefs, which are separated from volcanic islands by lagoons; and ring reefs, which enclose only a lagoon and are defined as atolls. Moreover, he linked these reef types through an evolutionary model in which an atoll is the logical end point of a subsiding volcanic edifice, as he was unaware of Quaternary glaciations. As an alternative, starting in the 1930s, several authors proposed the antecedent karst model; in this model, atolls formed as a direct interaction between subsidence and karst dissolution that occurred preferentially in the bank interiors rather than on their margins through exposure during glacial lowstands of sea level. Atolls then developed during deglacial reflooding of the glacial karstic morphologies by preferential stacked coral-reef growth along their margins. Here, a comprehensive new model is proposed, based on the antecedent karst model and well-established sea-level fluctuations during the last 5 million years, by demonstrating that most modern atolls from the Maldives Archipelago and from the tropical Pacific and southwest Indian Oceans are rooted on top of late Pliocene flat-topped banks. The volcanic basement, therefore, has had no influence on the late Quaternary development of these flat-topped banks into modern atolls. During the multiple glacial sea-level lowstands that intensified throughout the Quaternary, the tops of these banks were karstified; then, during each of the five mid-to-late Brunhes deglaciations, coral reoccupied their raised margins and grew vertically, keeping up with sea-level rise and creating the modern atolls.

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