Channel morphology, hydrology and geomorphic positioning of a Middle Miocene river system of the Siwalik foreland basin, India

Abstract

Systematic lithofacies, palaeocurrent, palaeomorphological and palaeohydrological analyses have provided detailed information about a hitherto unstudied river system of the Siwalik foreland basin of the Himalaya. Three distinct lithofacies associations, each representing a specific depositional setting, have been identified and named as ‘Facies Association A’, ‘Facies Association B’ and ‘Facies Association C’. The ‘Facies Association A’ comprises pebbly sandstone, cross-bedded sandstone, ripple-laminated sandy siltstone and bioturbated mudstone lithofacies and represents deposits of a braided channel. The ‘Facies Association B’ comprises cross-bedded sandstone, bioturbated mudstone, fine sandstone–mudstone alternation and lensoid to prismatic sandstone lithofacies and represents deposits of a channel, natural levee, crevasse-splay and flood plain of a meandering stream. The ‘Facies Association C’ comprises mottled siltstone–mudstone heterolith and fine sandstone lithofacies and represents deposits of the upland interfluve region. The braided stream had a maximum depth of 4.15 m, maximum width of 305 m and maximum discharge of 7045 cumec, whereas the meandering stream had a sinuosity of 1.26, maximum depth of 3.71 m, maximum width of 180 m and maximum discharge of 4070 cumec. The area had a regional radial outward flow pattern, but dominantly towards the SSW. However, the braided river had a bimodal flow pattern due to an active basement-high-induced bend along its course. A comparison of the sediment characters and morphological and hydrological parameters of these streams with those of the modern rivers of the Ganga (Gangetic) basin has enabled us to infer that this river system was located in the medial-distal megafan-interfan setting of the basin.

A review on out-of-sequence deformation in the Himalaya

“…Other than Malik et al (2014), no other reported research exists on these two faults. Note that the Tanakpur Fault, the Kalaunia Fault, the Chorgalli Fault, the Garampani -Kathgodam Fault, the Haldwani Fault and the Nihal Fault also continue in the Ganga foreland basin (Goswami & Deopa 2015;Yhokha et al 2015).…”

Petrotectonic setting of the provenance of Lower Siwalik sandstones of the Himalayan foreland basin, southeastern Kumaun Himalaya, India

“…Furthermore, the clustering of the data close to Qm apex, along the Qm‐Lt leg of the QmFLt plot suggests a substantially quartzose, and subordinately transitional (between quartzose and lithic), nature of the recycled orogen provenance (Figure b) (Dickinson, ; Dickinson et al, ). As a matter of fact, the sandstone samples analyzed in the present study belong to middle‐distal parts of large rivers (Goswami & Deopa, , ) and thus are excellent predictors of the paleotectonic setting of the provenance for they represent third‐order sands of actualistic sand petrofacies (cf. Ingersoll, Kretchmer, & Valles, ).…”

“…The sediments in the entire Lower Siwalik foreland basin have been deposited by a vast tributary network of southerly flowing braided, meandering and anastomosing river systems (Friend et al, ; Goswami & Deopa, , ; Huyghe et al, ; Nakayama & Ulak, ; Sharma, Sharma, & Singh, ; Shukla et al, ; Willis, ; Zaleha, ). The primary flow of the trunk stream in the western and central portions of this basin was southeasterly directed (Burbank et al, ).…”

“…So far, the sedimentology of the Siwalik sequence has been determined only along a few sectors of northwestern Pakistan, northwestern, northern and eastern India, and western and southeastern Nepal (e.g. Behrensmeyer & Tauxe, ; Burbank et al, ; Goswami & Deopa, , ; Khan & Tewari, ; R. Kumar et al, ; Najman, ; Nakayama & Ulak, ; Shukla, Bora, & Singh, ; Tandon, ; Taral & Chakraborty, and references therein). However, most of the studies carried out so far pertained to paleoenvironmental investigations whereas the studies focused on geomorphic, tectonic and lithological aspects of the source area of the detritus have only been limited (e.g.…”

“…Nevertheless, probably because of the dense forest cover, inaccessibility and intense deformation, the sedimentology of many parts of the Siwalik molasse has been ignored. The Lower Siwalik fluvial succession of southeastern Kumaun Himalaya of northern India is one such region, which remained ignored until Goswami and Deopa (, ) presented a systematic account of its depositional processes, channel morphology, hydrology and palaeogeography (Figure ). The present paper is a major supplement of our previous work and pertains to petrographic analyses of the Lower Siwalik sandstones of the area.…”