Testing the validity of Nd isotopes as a provenance tool in southern Tibet for constraining the initial India–Asia collision

Constraints on the timing of the India‐Asia collision and unroofing history of the Himalayan orogen using detrital zircon U‐Pb‐Hf and whole‐rock Sr‐Nd isotopes in Cretaceous‐Miocene Lesser Himalayan sedimentary rocks

“…The GH exhibits εNd( t = 0) and 87 Sr/ 86 Sr values of −15.3 ( n = 18) and 0.76495 ( n = 30), ranging from −19.9 to −7.6 and from 0.73110 to 0.79023 (Ahmad et al, 2000; Parrish & Hodges, 1996; Richards et al, 2005; Robinson et al, 2001), with average Nd and Sr concentrations of 27.0 ppm ( n = 30) and 88.8 ppm ( n = 18) respectively. The εNd( t = 0) values in the TH range from −20.1 to −5.1, with an average value of −12.9 ( n = 32) (Ahmad et al, 2000; Hu, 2012; Richards et al, 2005; Robinson et al, 2001) and 87 Sr/ 86 Sr ratios range from 0.7097 to 0.7329, with an average ratio of 0.7186 ( n = 34) generated from rivers draining across the Nepalese TH (Evans et al, 2001; Galy et al, 1999; Harris et al, 1998); the average Nd and Sr concentrations are 47.4 ppm ( n = 32) and 614.2 ppm ( n = 10) respectively. We conducted mixing calculations for the IYSZ ophiolite and Lhasa terrane with respect to the TH and GH, between the Rajmahal Traps and LH and between the TH and GH (Figure 10).…”