Variability in the crustal structure of the West Indian Continental Margin in the Northern Arabian Sea

Crustal structure of the Murray Ridge, northwest Indian Ocean, from wide-angle seismic data

“…However, northeastsouthwest striking basement fabrics are identified in this region by Malod et al (1997) and a northeast-southwest volcanic basement ridge, the Somnath Ridge, is present immediately to the northwest of the Saurashtra High (Calves et al 2011). Both features are consistent with northwest-southeast extension in this region, though the abrupt northwestern edge of the Saurathtra High has alternatively been interpreted as evidence for a transform margin here (Corfield et al 2010;Calves et al 2011). We therefore infer that extension in this region predates the formation of the Gop Rift and, based on our seismic velocity constraints, propose an ocean-continent transition further to the southwest than that proposed by Calves et al (2011;Fig.…”

“…153 Ma opening of the Somali Basin (Rabinowicz et al 1983). Based on seismic reflection and gravity data, Corfield et al (2010) infer a similar age for this basin, though they prefer an oceanic origin and implicitly a different direction of extension. This extensional episode may also explain thick pre-Deccan sedimentary deposits onshore in the Katchchh peninsula (e.g.…”

“…More recently, extensive industry seismic reflection data have shown the widespread presence of volcanics in this region, which has been subsequently named the Saurashtra High or Saurashtra Volcanic Platform. These data have led to an interpretation as highly stretched (10-12 km) continental crust overlain by thick volcanics or even as an oceanic plateau (Corfield et al 2010;Calves et al 2011). To the southwest of this basement high, in the Gop Rift and its northwestern extension, the presence of oceanic crust is inferred from wide-angle seismic data , from seismic reflection profiles exhibiting a typical oceanic Moho (Calves et al 2011) and from the presence of linear magnetic anomalies.…”

Integrated tectonic basin modelling as an aid to understanding deep-water rifted continental margin structure and location

“…• • break-up age 80 Ma (this is a simplifying approximation of a complex multi-phase break-up history (Corfield et al 2010)); • • reference Moho depth and initial crustal thickness 35 km;…”

“…Figure 2d shows the same map of crustal basement thickness, overlaid with an interpretation of the major structural elements picked out by the map (e.g. Talwani & Reif 1998;Daley & Alam 2002;Krishna et al 2006;Roberts 2008;Corfield et al 2010). Perhaps most interesting in this regional geological interpretation is the separation of the Laxmi Ridge continental block from the mainland India continental margin by the Laxmi Basin, which has a uniform crustal thickness of ~7 km, compatible with the presence of normal thickness oceanic crust between two continental blocks (see also Talwani & Reif 1998).…”