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Quartz

  Quartz   Quartz is hexagonal and commonly occurs as crystals ranging in size form microscopic to crystals weighing several tons. Where it crystallizes unhindered by other crystals, such as in cavities in rock or in a liquid containing few other crystals, it shows well-developed hexagonal prisms and sometimes showing apparent hexagonal pyramids or dipyramid. When it crystallizes in an environment where growth is inhibited by the surroundings, it rarely show crystal faces. It is also found as microcrystalline masses, such as in the rock chert, and as  fibrous masses, such as in chalcedony. Vitreous lusture.   As visible crystals, Quartz is one of the more common rock forming minerals. It occurs in siliceous igneous rocks such as volcanic rhyolite and plutonic granitic rocks. It is common in metamorphic rocks at all grades of metamorphism, and is the chief constituent of sand. Because it is highly resistant to chemical weathering, it is found in a wide variety of sedimentary r
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ORIGIN OF PETROLEUM (PART -1)

                                        FORMATION OF PETROLEUM BY THEORIES                                                               FIGURE : 1.1  PETROLEUM : Petroleum is also said to be an rock oil , which is a most important mineral fuel which is a complex mixture of hydrocarbon which comprises some minor impurities of nitrogen , oxygen , sulfur .   In other word liquid petrol is said as crude oil , petroleum gas is also known as natural gas Semisolid to solid form of petroleum is asphalt , tar, pitch, bitumen , etc...   The formation of petroleum comprises two theories they are :    INORGANIC THEORY   ORGANIC THEORY INORGANIC THEORY : Inorganic theory includes:-        Brethelot’s alkaline carbide theory        Mendelcef’s carbide theory        Moissan’s carbide theory       Cosmic theory      Brethelot’s alkaline carbide theory :                 This theory explains that the carbon-di-oxide reacts with alkaline metal in the interior of the earth at high temp
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Types Of Metamorphic Textures

  STRUCTURES OF METAMORPHIC ROCKS (MACROTEXTURES): (i)                 Slaty cleavage : A pervasive, parallel foliation (layering) of fine-grained platy minerals (chlorite) in a direction perpendicular to the direction of maximum stress. It produces the rocks slate and phyllite. (ii)           Schistose : Schist has a lepidoblastic foliation if this foliation is defined by oriented mica, and a nematoblastic foliation if such a foliation is defined by the orientation of prismatic minerals as amphiboles and pyroxenes. (iii)        Gneissic :   A complex banded texture made of schistose layers or bands alternating with bands commonly characterized by a granoblastic texture. (iv)            Granoblastic: Granular, interlocking equi-dimensional grains of subequal size; no preferred orientation or cleavage. (v)              Hornfelsic : Fine-grained, granular interlocking grains, possibly of variable shapes and sizes. No preferred orientation. (vi)              Cataclastic : •
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TEXTURES OF CLASTIC SEDIMENTARY ROCKS

TEXTURES OF CLASTIC SEDIMENTARY ROCKS           When sediment is transported and deposited, it leaves clues to the mode of transport and deposition. For example, if the mode of transport is by sliding down a slope, the deposits that result are generally chaotic in nature, and show a wide variety of particle sizes. Grain size and the interrelationship between grains gives the resulting sediment texture. Thus, we can use the texture of the resulting deposits to give us clues to the mode of transport and deposition.   Figure 1.1 - Type of sorting Sorting :-   The degree of uniformity of grain size. Particles become sorted on the basis of  density, because of the energy of the transporting medium. High energy currents can carry larger fragments. As the energy decreases, heavier particles are deposited and lighter fragments continue to be transported. This results in sorting due to density. If the particles have the same density, then the heavier particles will also be larger,
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SEDIMENTATION PROCESS

                                          SEDIMENTATION PROCESS                                        FIGURE 1.1 SEDIMENTARY ROCK  Rivers, oceans, winds, and rain runoff all have the ability to carry the particles washed off of eroding rocks. Such material is called as detritus , consists of fragments of rocks and minerals. When the energy of the transporting current is not strong enough to carry these particles, the particles drop out in the process of  sedimentation . This type of sedimentary deposition is referred to as  clastic sedimentation . Another type of sedimentary deposition occurs when material is dissolved in water, and chemically precipitates from the water. This type of sedimentation is referred to as  chemical sedimentation . A third process can occur, where in living organisms extractions dissolved in water to make such things as shells and bones. This type of sedimentation is called  biochemical sedimentation.  The accumulation of plant matter, such as at the bottom
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