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TEPP-00 Survey

VSA Author: Gerome Calves
Organization: University of Aberdeen
Regions: 2
Scenes: 0
Interpretations: 0
Date Created: 2011-06-22

This seismic reflection survey located offshore Pakistan (Indian Ocean) documents the northern part of the Indian Margin evolution from rifting to present day geometry of the Indus Fan. Two regional lines have been selected from a published paper in 2011 (JGR-AGU) that you can access using the docs and links. A location map for the two lines is attached in the docs and links. A specific seismic facies chart is proposed for the volcanostratigraphic features observed below the Indus Fan sequence (docs and links). Abstract: The Indian Plate has been the focus of intensive research concerning the flood basalts of the Deccan Traps. Here we document a volcanostratigraphic analysis of the offshore segment of the Western Indian volcanic large igneous province – between the shoreline and the first magnetic anomaly (An28 ~63 Ma). We have mapped the different crustal domains of the NW Indian Ocean from stretched continental crust through to oceanic crust, using seismic reflection and potential field data. Two volcanic structures, the Somnath Ridge and the Saurashtra High are identified, extending ~305 km NE-SW in length and 155 km NW-SE in width. These show the internal structures of buried shield volcanoes and hyaloclastic mounds, surrounded by mass-wasting deposits and volcanic sediments. The structures observed resemble seismic images from the North Atlantic and Northwest Australia, as well as volcanic geometries described for Réunion and Hawaii. The geometry and internal seismic facies within the volcanic basement suggests a tholeiitic composition and subaerial to shallow marine emplacement. At the scale of the Western Indian Plate, the emplacement of this volcanic platform is constrained by structural lineations associated with rifting. By reviewing the volcanism in the Indian Ocean and plate reconstruction of the area, the timing of the volcanism can be associated with eruption of a pre-Deccan continental flood basalt (~75–65.5 Ma). The volcanic platform in this study represents an addition of 19–26.5% to the known volume of the West Indian Volcanic Province.



Regional Projects related to this Survey

TEPP00-128 Regional Project

VSA Author: Gerome Calves
Scenes: 2
Interpretations: 1
Date Created: 2011-06-29

Seismic reflection line (orientation NW-SE), (A) potential field data, (B) seismic image of Murray Ridge, Somnath Ridge and Saurashtra High. The line location shown in base map in the docs and links tab of the main VSA survey.

TEPP00-207 Regional Project

VSA Author: Gerome Calves
Scenes: 1
Interpretations: 1
Date Created: 2011-06-29

Seismic reflection line (orientation NE-SW), (A) potential field data, (B) seismic image interpretation of Somnath Ridge and Saurashtra High (yellow lines are carbonates platforms overlying the seismic basement), and (C) detailed interpretation of white box in B (TEPP00-207_interpretation) : seaward-dipping reflector sequences (SDRs), and Moho reflection and hyaloclastic delta. This s...



Details:

  • Survey Administrator:
    • Gerome Calves
  • VSA Author:
    • Gerome Calves

Geological Context

Plate Settings and Margins
Transform, Divergent (constructive), Passive

Tectonics
Igneous structures, Rifts

Basin Setting
Passive Margin

Geographic Context

Physical Geography
Fans (Submarine)

Political Geography
Pakistan, Islamic Republic of

Geophysics

Survey Information
Marine, Multichannel 2D, >10s, Migrated

Data Presentation
Vertical Scale - Time, Amplitude

Image Type
Horizon/Surface Map, Vertical Profile