Geochemical Characteristics on NW of Ladakh Batholith region exposed in the Western part of Leh area around Trans- Himalayan Belt, NW (India)

The geochemical characteristics (major & trace elements including REE) are studied on the granitic rocks from NW of Ladakh batholith region that emplaced in the western part of Leh area around the Trans- Himalaya of Ladakh district, Jammu & Kashmir (NW India). The major element geochemistry reveals that these granitic rocks display a broad spectrum of SiO2 content (54.50 wt%- 75.80 wt%). The oxide of K2O, Al2O3, MgO & Fe2O3 shows negative correlation with SiO2 probably shows the fractionation of biotite during the process of crystallization. The oxide of CaO & TiO2 shows positive correlation that coupled with their negative correlation with SiO2 most probably reflects the fractionation of Sphene (CaTiSiO5). The fractionation of apatite is also indicated by the positive correlation with CaO & P2O5 and their negative correlation with SiO2. The classified diagram between Molar Al2O3/ (CaO+Na2O+K2O) vs Molar Al2O3/ (Na2O+K2O) shows that all samples covered peraluminous region. The total alkali diagram of (Na2O+K2O) wt% vs SiO2 (wt %) shows that all samples covered the region of granite, quartz diorite & diorite. The samples plot between K2O (wt %) vs SiO2 (wt %) shows high to medium -K (calc-alkaline) series. All these intrusive rock shows enrichment in LILE (K, Rb, Ba, & Th) and LREE (Ce) relative to the HFSE (Ta, Nb, Hf, Zr, Sm, Y, & Yb). The Chondrite- normalized REE patterns for the studied granitic rocks such as LREE & MREE and HREE's are moderately fractionated & have moderate negative Eu anomalies. In the Nb Vs Y and Rb- (Y+Nb) diagrams, all intrusive rocks fall into the VAG (volcanic- arc granite) field in order to characterize tectonic environment for the granitic rocks. The Al2O3/TiO2 vs CaO/Na2O diagram & Rb/Ba vs Rb/Sr plots are used for identifying the source of melts parental to peraluminous granites. The variations that observed in granitoid are not only by partial melting but also depend on various processes like migration of melts, magma mixing, assimilation & fractional crystallization. Geochemical studies indicate strong peraluminous behavior with high content of SiO2, K2O/ Na2O ratio that suggest the characteristics of S- type granite. Most of the granitoid samples indicate their volcanic-arc nature but some of them shows syn- collisional tectonic setting as well.