GEOCHEMISTRY AND PETROGENESIS OF ACID MINOR BODIES OF MANSEHRA AND BATGRAM AREA, HAZARA DISRICT

Title of Thesis
GEOCHEMISTRY AND PETROGENESIS OF ACID MINOR BODIES OF MANSEHRA AND BATGRAM AREA, HAZARA DISRICT
Author(s)
Muhammad Ashraf
Institute/University/Department Details
University Of The Punjab
Session
1974
Subject
Geology
Number of Pages
273
Keywords (Extracted from title, table of contents and abstract of thesis)
acid minor bodies, sedimentary rocks, granitic complex, basic minor intrusives, albite, quartz veins, pegmatitic-albitites, albite-microcline, microcline-albite-aplites
Abstract
The acid minor bodies in the mansehra and Batgram area were emplaced in the granitic rocks and the associated met sediments. These bodies have been identified as ( i ) Albities, (2) albiteaplites/pegmatites, (3) ablate-(microcline )-aplites /pegmatites, (4) alit-microcline-aplites/tit/pegmatites, (5) microcline-albiteaplies/pegatites and (6) complex aplites/pegmatites. The first 4 types occur as independent and composite bodies in the interior-lateral zone (1750 to 5500 feet above sea level), types 4 and 5 occur in the interior-marginal zone (5000 to 9000 feet above sea level) and types 5 and 6 are present in both interior-marginal zone and marginal �€“ exterior zone (over 9000 feet sea level). Field, mineralogical and chemical evidences show that the acid minor bodies are genetically related with the granitic rocks of the area. This genetic relationship is significant due to continued enrichment of soda in the granites from susalgali granitic gneiss (a potassic facies) to Hackle tourmaline granite and chail sar micro granite. The enrichment of soda is due to gradual cooling and increases in vapor pressure of the complex (in tightly closed environments) more than to kbs, where the acidic fluids shifted toward the albite apex. From this the release in external pressure at within the interior-lateral zone gave rise to soda rich liquids being deposited in the fissures. These fissures provided the local in pressure by the opening the metasodiuments during the welling up and the expansion of the granites in the diapiric and much room like structures. Therefore, as the vapour pressure decreased with further cooling, the behavior of the system was reversed gradually, meaning thereby that quantity depended on the release in p(H2o) in the three structural zones. The mineralogy and chemistry of these structural units is quite contrasting with the exception of some overlapping at places. Therefore, the present investigations show that the pegmatite residual solutions were derived from the albite rich solutions gradually with the introduction of k2 o and volatiles. This derivation is excellently exemplified by negative correlation of Na2o and positive correlation of k2o with Si02 and gradual but significant increase in the rare elements.
 
 

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