Characterization of Granite

Theses Ppt is about Characterization of Granite on the basis of field relation around dharoi and Taranga hill

1. CHARACTERISATION OF GRANITE ON THE BASIS OF FIELD RELATION IN AND AROUND DHAROI , TARANGA HILL , MAHESANA DISTRICT,Gujarat; india BY DARSHAN DARJI AKASH LIMBACHIYA UNDER THE GUIDANCE OF MS. MADHUMAYEE MOHANTA MS.NAYANI DAS GEOLOGIST, GEOLOGICAL SURVEY OF INDIA M.G. Science Institute (Geology Department) Navrangpura,Ahmedabad,Gujarat 380009 [email protected]

2. CONTENT Objective Location and accessibility Physiography Geology of the study area Lithostratigraphy of the study area. Conclusion References

3. OBJECTIVE Characterization of granite in and around Dharoi , Taranga hill , mahesana District, Gujarat.

4. LOCATION AND ACCESSIBILITY Toposheet no. 45D/16 OR 46A/13 of Mahesana District of Gujarat Study Area ΄ s

5. GOOGLE EARTH IMAGE OF STUDY AREA ΄ s Study Area ΄ s Source : Google earth image

6. PHYSIOGRAPHY Symbol layer name legend VELYU Physiography of study area Source : BHUKOSH, GSI

7. GEOLOGY OF THE STUDY AREA Table source : Ahmad, T. and Tarney, J., 1994. Paleo to Mesoproterozoic

8. Taranga Hill

9. LITHOSTRATIGRAPHY OF THE STUDY AREA Aeolian sand/Soil cover Quartz vein Pegmatite vein Microgranite/Microgranite dyke K-feldspar rich porphyritic granite Plagioclase rich porphyritic granite Microgranite Calc silicate Gneiss (Delhi Super group) Not exposed in study area Sendra-Ambaji granite

10. SENDRA - AMBAJI GRANITE intrusion Two variants of Sendra Ambaji granitoids : Plagioclase rich porphyritic granite K-feldspar rich porphyritic granite Medium to coarse grained. Grey to white/pinkish in colour . Composed of quartz , orthoclase , plagioclase , biotite and amphibole . Feldspar phenocryst size : 1-5 cm

11. Plagioclase rich porphyritic granite near Taranga road section   Feldspar phenocryst 3.5 cm size in porphyritic granite

12. K-feldspar rich porphyritic granite near Dharoi Dam

13. Microgranite rock found north of maneknath temple

14. Pegmatite veins Pegmatite vein in Micro Granite rock near vekari village Pegmatite vein

15. Igneous Intrusion Terrain Metamorphic Terrain CA - SI VEIN Smokey Quartz

16. ALTERATION The hydrothermal alteration of the granite proceed mainly by dissolution- Precipitation process resulting from the infiltration of hydrothermal fluid along the microcracks. Alteration of rock in which plagioclase is albitized freeing the anorthite molecule for the formation of epidote.

17. Fluorite vein in granitic rock Silicification in granitic rock

18. JOINTS & STRUCTURE 2 set joints Trending 280,255 Respectively

19. Mafic microgranular enclaves (MME) are commonly found in granodiorites and monzogranites and have sharp contacts with the host rocks. Sometimes, the fine veins of the host rocks cut through the enclaves. Tafoni weathering Known as honeycomb weathering or "Swiss-cheese rock," Tafoni (singular: tafone) are small, rounded, smooth-edged openings in a rock surface, most often found in arid or semi-arid desert

20. SKARN DEPOSITS Skarn deposits are developed due to replacement, alteration, and contact metasomatism of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body. They most often develop at the contact of intrusive plutons and carbonate country rocks. Skarn deposits are one of the more abundant ore types in the earth's crust and form in rocks of almost all ages. Skarn is a relatively simple rock type defined by a mineralogy usually dominated by calcsilicate minerals such as garnet and pyroxene. In near Dharoi region we found skarn deposits replacement, alteration, and contact metasomatism of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body. We Epidote, Diopside, Fluorite, Garnet Bearing Granite Rock.

21. Fluorite Diopside Epidote

22. Conclusion In the context of present study, toposheet no. 45D/16and 46A/13 an area of Dharoi, Taranga hill area of mahesana District northern Gujarat. The major lithounits observed are K- feldspar rich granite and plagioclase rich granite, deformed quartzofeldspathic veins, graphic granite veins and reef and pegmatites, intruded by quartz veins. This porphyritic, undeformed granite is the youngest granitic phase of Sendra-Ambaji suite. Such occurrences of wollastonite + andalusite + tourmaline within argillaceous calc gneiss demarcate the skarn zone, likely formed by replacing impure carbonate rock or dolomite adjacent to granitic intrusive, probably at shallow crustal depth with the advent of post magmatic ascending hydrothermal solutions involving “infiltration metasomatism”.

23. Continue… Porphyritic granite is relatively enriched in total REE (∑ REE) concentration compared to granite and gneiss showing similar REE pattern which suggests their similar magmatic evolution. The trace elements and REE distribution patterns of granite gneiss and porphyritic granite show positive (+ ve) Th, Rb, K and La anomaly and negative (-ve) Ba, Nb, Sr and Ti anomaly, indicating subduction zone granitic magmatism Thus it is apparent that the time span between the tectono-thermal events associated with the emplacement of the Sendra-Ambaji Granites at ~ 960 – 850 Ma.

24. references Geology and mineral resources of Gujarat ,Daman and Diu published by GSI No.30 part 14 2012, pp. 11 Geochemistry and petrogenesis of late Archaean Aravalli volcanics, basement enclaves and granitoids, Rajasthan. Precambrian Research. Arindam Dutta, Shukla Dutta and Gagan Chandra Barik, Geologists, SPECIALISED THEMATIC MAPPING OF THE DELHI SUPERGROUP OF ROCKS IN DANTA-BHANPUR AREA OF BANASKANTHA DISTRICT OF GUJARAT (Final Report for Field Season 2012-14) Gupta, S.N., Mathur, R.K. and Arora, Y.K., 1992. Lithostratigraphy of Proterozoic rocks of Rajasthan and Gujarat - a review. Rec. Geol. Surv. India, v , pp. 63-85 https://www.sciencedirect.com/ (SKARN DEPOSITS) https://www.nps.gov/ (Tafoni weathering) https://onlinelibrary.wiley.com/ (Mafic microgranular enclaves)