~ 656 ~  ISSN Print: 2394-7500 ISSN Online: 2394-5869 Impact Factor: 5.2 IJAR 2015; 1(9): 656-661 www.allresearchjournal.com Received: 28-06-2015 Accepted: 30-07-2015 Yadav RN Department of Geology, Banaras Hindu University, Varanasi-221005. Sen Gupta D Department of Geology, Banaras Hindu University, Varanasi-221005. Sen Gupta HP Department of Geology, Banaras Hindu University, Varanasi-221005. Correspondence Yadav RN Department of Geology, Banaras Hindu University, Varanasi-221005. High temperature diagenetic magnesite deposit of Jhiroli, Kumaon lesser Himalaya, India Yadav RN, Sen Gupta D, Sen Gupta HP Abstract Jhiroli magnesite deposit of Kumaon Lesser Himalaya is associated with dolostone of Deoban Formation. It occurs in bedded nature and mainly crystalline form with fairly coarse crystals. Development of stromatolites is observed which played important role in the formation of magnesite. The relationship between magnesite and different associated constituents exhibits the most interesting and varied assemblages of textural and structural features. Geochemical studies reveal that the magnesite is predominantly composed of MgO and volatile constituent i.e. carbon dioxide as established by its relationship with carbonate content. Except Cao, MgO and Sr there is no noteworthy variation in the other major and trace element distribution of the magnesite and the host dolostone. Fluid inclusion studies in magnesite and dolomite suggest that the magnesitizing fluids were aqueous NaCl brines of variable salinities ranging from 6.37 to 35.65 wt% NaCl equivalent. The maximum homogenization temperature of magnesite in triphase fluid inclusion ranges between 260 0 and 270 0 C but in the case of biphase fluid inclusion maximum homogenization temperature of dolostone and magnesite is almost same and ranges between 220 0 and 230 0 C. These homogenization temperatures are within the range of diagenetic recrystallization. Based on the above observations it is concluded that the magnesite is of diagenetic origin under high temperature restricted basin and lagoonal setting. Keywords: High temperature, diagenetic magnesite, Jhiroli, Kumaon lesser Himalaya 1. Introduction The present investigation covers the potentially important crystalline magnesite deposits of Bilori-Jhiroli-Naini belt. It is situated between latitude 29 0 45’30” and 29 0 47’30” N and longitude 79 0 44’and 79 0 46’. Mineralization occurs in the form of beds, which generally dips 20 0 to 26 0 towards NNE. Deoban Formation consists of a very thick pile of calcareous and siliceous metasedimentary rocks belonging to Kumaon Lesser Himalaya of Upper Middle Riphean age. But according to other workers Gangolihat Dolomite (Deoban and equivalent formation) of Inner Kumaon Lesser Himalaya is regarded as Precambrian – Cambrian boundaries (544Ma) on the basis of protoconodonts. The geological succession of the study area is given in table 1. Table 1: Generalized Geological Succession of the Study Area (modified after Valdiya, 1980). International Journal of Applied Research 2015; 1(9): 656-661