Magnetic polarity stratigraphy of the Neogene Siwalik Group at Khutia Khola, far western Nepal

Climatic and tectonic controls on sedimentation and erosion during the Pliocene-Quaternary in the Qaidam Basin (China)

“…Stratigraphic horizons that contained only one sample with a specifi c polarity, which could not be replicated, are illustrated in Figure 9 as gray zones, but they are not discussed in the results or used in the magnetostratigraphic correlation. Many previous magnetostratigraphic studies employed a methodology that ranks sites based on two or more samples per site (e.g., Johnson et al, 1982;Kempf et al, 1998;Schlunegger et al, 1997;Ojha et al, 2000;Chen et al, 2002). Given that studies of correlative, nearby Qaidam Basin strata found magnetizations to be relatively straightforward in terms of polarity (N or R) determination ( Fig.…”

Detrital zircon U–Pb geochronology of the Siwalik Group of the Nepal Himalaya: implications for provenance analysis

“…The topmost Upper Siwalik is predominantly composed of pebble to boulder conglomerates with lesser amounts of sand facies (Tokuoka et al 1986(Tokuoka et al , 1990Dhital et al 1995;Nakayama and Ulak 1999). The age of the Siwalik Group ranges from 13.2 to 1 Ma in Nepal, obtained from magnetostratigraphy (Appel et al 1991;Gautam and Rösler 1999;Ojha et al 2000Ojha et al , 2009Gautam et al 2012) and biostratigraphy (Corvinus 1988). The geology of the present study areas (Surai Khola and Koshi Nadi sections, Fig.…”

“…In this regard, foreland basin sediments of the Siwalik Group have been extensively studied to reconstruct the paleogeography (Miall 1995;DeCelles and Giles 1996;Sinclair 1997;DeCelles et al 1998a), constrain the rate and timing of Himalayan exhumation (Dickinson 1985;DeCelles and Giles 1996;Mugnier et al 1999) and understand paleohydrology (Huyghe et al 2001(Huyghe et al , 2005Ulak 2005). Along the Nepal Himalaya, geochronological studies have established depositional age from 13.2 Ma spanning a period till 1 Ma (DeCelles et al 1998a, b;Ojha et al 2000;DeCelles et al 2001DeCelles et al , 2004Szulc et al 2006;Chirouze et al 2012), which corresponds to the age ranges yielded by paleomagnetic studies (Appel et al 1991;Harrison et al 1993;Gautam and Rösler 1999;Gautam et al 2012). Similarly, there are number of milestone works in the northwestern Himalaya that interlinked the erosional records of the foreland basin with tectonic history (Burbank et al 1996;Najman et al 2004;Jain et al 2009;Najman et al 2009).…”

Magnetic polarity stratigraphy of the Siwalik sequence in Nurpur area, NW Himalaya, India

“…The specimens were demagnetized using Schonstedt Thermal Demagnetizer (TSD-1) at 12-13 temperature steps from 100 • to 700 • C. Figure 2 shows the typical thermal demagnetization behaviours for middle and upper Siwalik samples. The high unblocking temperature components are carried by specular haematite that acquired a magnetization either as detrital remanent magnetization or chemical remanent magnetization soon after deposition (Tauxe and Badgely 1988;Tauxe et al 1990;Ojha et al 2000). Principal component analysis of NRM remaining at two to three successive temperature steps from 575-625 • C was used to determine the ChRM (Kirschvink 1980).…”