Identification of new deep sea sinuous channels in the eastern Arabian Sea

Abstract

Deep sea channel systems are recognized in most submarine fans worldwide as well as in the geological record. The Indus Fan is the second largest modern submarine fan, having a well-developed active canyon and deep sea channel system. Previous studies from the upper Indus Fan have reported several active channel systems. In the present study, deep sea channel systems were identified within the middle Indus Fan using high resolution multibeam bathymetric data. Prominent morphological features within the survey block include the Raman Seamount and Laxmi Ridge. The origin of the newly discovered channels in the middle fan has been inferred using medium resolution satellite bathymetry data. Interpretation of new data shows that the highly sinuous deep sea channel systems also extend to the east of Laxmi Ridge, as well as to the west of Laxmi Ridge, as previously reported. A decrease in sinuosity southward can be attributed to the morphological constraints imposed by the elevated features. These findings have significance in determining the pathways for active sediment transport systems, as well as their source characterization. The geometry suggests a series of punctuated avulsion events leading to the present array of disconnected channels. Such channels have affected the Laxmi Basin since the Pliocene and are responsible for reworking older fan sediments, resulting in loss of the original erosional signature supplied from the river mouth. This implies that distal fan sediments have experienced significant signal shredding and may not represent the erosion and weathering conditions within the onshore basin at the time of sedimentation.

Depositional History and Indian Summer Monsoon Controls on the Silicate Weathering of Sediment Transported to the Eastern Arabian Sea: Geochemical Records From IODP Site U1456 Since 3.8 Ma

“…These particles would instead be deposited on the continental shelf (Kessarkar et al, ). Compared to the rivers crossing the Deccan Traps, there was significantly greater sedimentary flux from the paleo‐Indus River due to enhanced physical erosion, with increased input of weathering and erosion products to the study area over long distances despite the weak monsoon currents (Rao & Rao , ; Shetye et al, ), as most sediment is likely to be transported by deep‐sea channels instead of transported as plumes in the upper parts of the water column (Mishra et al, ; Yu et al, ). Sea‐level changes inferred from eastern Mediterranean δ 18 O values show that the sea level was at a highstand at this time.…”

Demographics and length and weight relationships of commercially important sharks along the north‐western coast of India

“…In contrast, S. laticaudus is primarily an inshore species, whereas R. oligolinx and R. acutus are shelf species (Ebert et al, ). The continental shelf of Gujarat extends up to 100 km and more from the shore (Mishra, Pandey, Ramesh, & Clift, ), with a very gradual slope offering these four species their preferred range of habitats and thus explaining their presence through the year in these waters.…”

Tectonic Evolution of a Sedimented Oceanic Transform Fault: The Owen Transform Fault, Indian Ocean

“…The present‐day morphology of the proximal (upper) Indus Fan is marked by large channel‐levee systems (Kolla & Coumes, 1987; Mishra et al., 2016; Von Rad & Tahir, 1997), while over the distal (lower) Indus Fan system, levees become smaller, channels are less numerous and the distance between channels increases (Kolla & Coumes, 1987). Far from the sources, the sedimentary cover is thus marked by an alternation of turbidites (in the vicinity of an active turbiditic channel) and pelagites (when channels migration took them further) (Shipboard Scientific Party, 1989a; Von Rad & Tahir, 1997).…”