Ahmedabad is situated in Central Gujarat. It is eleventh largest district. It lies between 20-0 and 23-4 North latitudes and 71-6 and 72-9 East longitudes. The north side of the district is bound by the Mehsana and Gandhinagar district, north-east by the Sabarkantha district and south by the Kheda district and Gulf of Cambay. The western side of the disrtict is bound by the Bhavnagar and the Surendranagar district. Ahmedabad, the district headquarters was also the state’s capital rom May 1960 to May 1970, before it was shifted to the new township at Gandhinagar. Climate, Rainfall, Temperature & Humidity. The climatic condition is favourable to the soil. The weather condition seasonally changes from winter to monsoon. The winter is extremely cold during December-January and summer is hottest in May-June while the monsoon sets in by middle of June to August and the average raifall is 650-750 mm. During the south-west monsoon season the relative humidity is generally 60% and over. In the rest of the year, the air is comparatively dry. In summer season humidity is 25% while in monsoon generally the rainfall occurs whenever the relative humidity is more than 80%. GENERAL GEOLOGY : The entire area of Ahmedabad district comprises of a cover of thick Alluvium with a few sporadic outcrops of Deccan Trap and Limestone towards southern part of the region. The area is almost flat covered by brown sandy and clayey soil and has gentle southerly and south westerly slope. It forms part of cambay basin. The sub surface geological history of the Ahmedabad District has to beunderstood along with that of the entire cambay sedimentary basin as the area covered by this district forms but a small part of it. Dhandhuka Taluka of the district minor ridges of Limestone of Cretaceous age and Trap rocks are forming Geophysical investigations were carried out by O.N.G.C. for the search of oil. On the basis of their findings the succession of the rock type in the area are as follows :-

AGE FORMATION LITHGOGY Holocene Alluvium Soil, Alluvium and Brown sand Post Miocene Jambusar Coarse grained sand with clay Bharuch Greyish Brown clay Jhagadia Greenish grey Claystone with minor coal. Miocene Kand Claystone with sand Babaguru Claystone and shale with minor sandstone Tarkeshwar Shale with sand ------------------------------Unconformity--------------------- Oligocene Tarapur Shale Shale with sandstone in lower portion to Upper Eocene Kalol Grey shale with silty sandstone, silt-stone and minor coal bed. ------------------------------Unconformity---------------------- Lower Cambay Shale Dark grey Carbonaceous shale with changes to trap, conglomerate towards margins. ------------------------------Unconformity---------------------- Lower Eocene to Intertrappean Bed Deccan Trap Upper (Creataceous)

USEFUL MINERALS : Ahmedabad district is not much important in respect of mineral resources except oil and gas. However, the important economic minerals available in the district are Sand, Kankar, Gravel, Brick, Earth and Limestone. SAND, KANKAR ETC. The river Sabarmati is the main source for the production of sand, kankar and gravel. The brown coloured alluvial formation of the recent and sub-recent age are used in manufacturing of brick for building purposes on a very large scale. LIME STONE : Limestone of cretaceous age is found to occur in Dhandhuka Taluka of the district. The important localities are Jalia, Sarangpur, Khambalia etc. It is mainly used for building purposes. TRAP : Trap rocks are available in the western part of Dhandhuka Taluka of Ahmedabad District. The important localities are Kinara and Umrala. It is mainly used as road metal and construction purpose.

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