The Chamba\|Bharmaur syncline located in between Zanskar range in the north and Dhauladhar\|Pirpanjal range in the south , in the Chamba district of Western Himachal Pradesh. The rocks constituting Chamba\|Bharmaur sy...The Chamba\|Bharmaur syncline located in between Zanskar range in the north and Dhauladhar\|Pirpanjal range in the south , in the Chamba district of Western Himachal Pradesh. The rocks constituting Chamba\|Bharmaur syncline belong to Precambrian to Lr. Triassic (Rattan, 1973) and represent the southern extension of the Tethyan facies of the Zanskar Tethys Himalayan sequence (Thakur, 1998). The geological and structural mapping in the Chamba\|Bharmaur syncline reveal that the area comprises of various litho\|units which show imprint of various phases of deformation. Three main phases of deformation DF\-1, DF\-2 and DF\-3 have affected the rocks of the Chamba\|Bharmaur syncline. The earliest recognisable deformational structures of the area are tight isoclinal folds appressed with long drawn out limbs and thickened hinges have experienced buckle shortening of 80%. They have been rendered intrafolial folds in many places; only a few of them show disharmony. The folds initiated in the multilayered sequences are generally controlled in their distribution and wave\|length by more competent members of the sequence.展开更多
Phosphate nodules from the Upper-Carboniferous to Upper-Permian period were discovered in the Chamba District of Himachal Pradesh.They are hosted by the Salooni formation and are sporadically found in black carbonaceo...Phosphate nodules from the Upper-Carboniferous to Upper-Permian period were discovered in the Chamba District of Himachal Pradesh.They are hosted by the Salooni formation and are sporadically found in black carbonaceous slate.They are grey to black coloured and vary from sub-round to oval shape,often exhibiting sharp conchoidal fractures.The petrography,X-ray diffrac-tometry(XRD),and scanning electron microscopy(SEM)reveal that the phos-phate mineral assemblages are dominated by cryptocrystalline apatite,namely collophane(carbonate fluorapatite or CFA)in studied samples.Quartz veins are often found in the nodules,along with associated gangue minerals,includ-ing,microcrystalline silica,carbonate and pyrite as minor constituents.The findings of the textural study show that the phosphates are present in both the pelletal form as well as apatite-rich matrix together with microfossil remnants.Clay minerals fillings suggest the intense chemical weathering of continental sources.The outcomes of this study suggest that the variations in the mineral morphologies,texture,and presence of organic matter within the phosphate nodules may be a result of early diagenesis precipitation of Carbonate Fluo-rapatite(CFA)crystals in the porewater with the help of activity of microor-ganisms at the sediment-water interface.展开更多
文摘The Chamba\|Bharmaur syncline located in between Zanskar range in the north and Dhauladhar\|Pirpanjal range in the south , in the Chamba district of Western Himachal Pradesh. The rocks constituting Chamba\|Bharmaur syncline belong to Precambrian to Lr. Triassic (Rattan, 1973) and represent the southern extension of the Tethyan facies of the Zanskar Tethys Himalayan sequence (Thakur, 1998). The geological and structural mapping in the Chamba\|Bharmaur syncline reveal that the area comprises of various litho\|units which show imprint of various phases of deformation. Three main phases of deformation DF\-1, DF\-2 and DF\-3 have affected the rocks of the Chamba\|Bharmaur syncline. The earliest recognisable deformational structures of the area are tight isoclinal folds appressed with long drawn out limbs and thickened hinges have experienced buckle shortening of 80%. They have been rendered intrafolial folds in many places; only a few of them show disharmony. The folds initiated in the multilayered sequences are generally controlled in their distribution and wave\|length by more competent members of the sequence.
文摘Phosphate nodules from the Upper-Carboniferous to Upper-Permian period were discovered in the Chamba District of Himachal Pradesh.They are hosted by the Salooni formation and are sporadically found in black carbonaceous slate.They are grey to black coloured and vary from sub-round to oval shape,often exhibiting sharp conchoidal fractures.The petrography,X-ray diffrac-tometry(XRD),and scanning electron microscopy(SEM)reveal that the phos-phate mineral assemblages are dominated by cryptocrystalline apatite,namely collophane(carbonate fluorapatite or CFA)in studied samples.Quartz veins are often found in the nodules,along with associated gangue minerals,includ-ing,microcrystalline silica,carbonate and pyrite as minor constituents.The findings of the textural study show that the phosphates are present in both the pelletal form as well as apatite-rich matrix together with microfossil remnants.Clay minerals fillings suggest the intense chemical weathering of continental sources.The outcomes of this study suggest that the variations in the mineral morphologies,texture,and presence of organic matter within the phosphate nodules may be a result of early diagenesis precipitation of Carbonate Fluo-rapatite(CFA)crystals in the porewater with the help of activity of microor-ganisms at the sediment-water interface.
