Rocks and manifestations of weakness:
Part of the dry land of different types of rocks consist can be defined as any rock material composed mainly of metal and one or a mixture of several metals and participate in the construction of an essential part of the earth's crust. There are also some rocks that consist of organic origin (non-metallic) rocks such as coal and organic rocks formed by the accumulation of skeletal remains of living organisms.
On this basis, the rock Peña vary depending on the type of metal constituents and the ratio of common metals in its composition as well as how its inception and how their presence Mode of Ocurresence.
Some of these rocks form strong blocs and some have little resistance and have some rock masses large and wide while the small be other, so the nature of the rock and regularity and place and structure are important factors in influencing the behavior of rivers and other virtual agents by exposing the dry blocks the process.
The quality of the rock LITHOLOGY affect the origins and evolution of many of the processes and forms the floor, which could be classified according to the types of rocks that comprise it, such as those forms that are associated with rocks limestone (karst topography), and forms the rocks and granitoid rocks sand. Surface monuments are formed by deposition and sculpture factors depend to a large extent on the nature of the rocks that fall under the region concerned. Many of the students tackled the subject Ackah- relations geomorphological in different regions, Caldrasat carried out by both Thomas and Jnnj and Twaedel, and focused them on highlighting the role of the quality of the rock in the development of the earth in general forms, and at the expense of other geomorphological factors sparking controversy is unnecessary about the priority and importance of any of these factors. In fact, environmental factors interfere together, including Jawmorvologih factors, in the production of any group of landforms in different places, and some of them emerged as a major factor or cushions Prevailing Factor in a specific environment. The quality of the rock may be the dominant factor in the region, while giving way to a climate or geological or human infrastructure in other regions. In this case, reflect the evolving landforms above a certain type of rock impact of these factors, just as happens for the forms of the surface of the cutting-edge rock limestone in both the dry areas and wet areas, because of differences in the complexity of the rocks found even in limited areas, or as a result of physical and chemical characteristics of the rock Himself. The limestone rocks of the weakest due to severe susceptibility to melt, but it is a clear resistance in dry areas and so are less likely to change when the change in temperature, and does not happen to other rocks.
Rock types:
It can be divided into the rocks by the way its inception into three sections:
1. igneous rocks
2. sedimentary rocks
3. metamorphic rocks.
Called igneous rocks and metamorphic rocks sometimes crystalline name.
As an initial distinction can be made between these three main types of rocks on the basis that sedimentary rocks are often in the form of layers may be homogeneous or mixed and each layer of these layers contain animal remnants and vegetable old called excavations (Fossils) and lacking completely this feature in igneous rocks it is rare that these fossils are found in metamorphic rocks because they decompose and disappear as a result of pressure and heat, and is characterized by igneous body Ktlah not a class, but often in the amorphous state, while rare presence of such crystalline components in the sedimentary rocks and crystals appear in many of the metamorphic rocks.
First: sedimentary rocks:
If we take into consideration the Earth's surface and entirely van segment, which consists of sedimentary rocks are much wider than those in which the metamorphic and igneous rocks exist collectively. This suggests that very large areas of the continental bodies were immersed in a time of times below the sea's surface, however, there sedimentary formations and wide not formed by deposition under water. Examples include the broad alluvial plains of up to hundreds of miles was formed at the foot of the mountains. The thickness of Sediments sometimes thousands of feet.
Sedimentary rocks consisting of freeze and cohesion rocky sediment and so Baltham components together under the emerging pressure from the weight of other sediments overlying, or may be cohesion and freezing by adhesive or carnivorous, such as calcium carbonate or silica or iron oxides that may exist between these deposits effect, VCD sedimentary rocks of materials and installation of multi-origin chemical or metallic anisotropic and under a variety of circumstances and different environments, and lead such a situation to many types of these rocks and sedimentary rocks are divided by way of composition and conditions of its inception into three main sections:
A sedimentary rocks mechanical upbringing:
This group includes all sedimentary rocks consisting of cut shredders previous rocks, which have been transported by water, wind or refrigerators or by gravity, without having undergone any chemical change and then deposition automatic and hold together and fuse, such as sandstone and child rocky complexes and certain types of Limestone. Divided sedimentary rocks mechanical upbringing in terms of grain size to:
1. sedimentary rocks Mechanical great upbringing grained and consists of a large-sized granules with a diameter of at least 2 mm and sometimes up to a few centimeters and know these General gravel Among the most important of these rocks and boulders Alkoonjlomirat Conglomerate breccia.
2. sedimentary rocks mechanical Growing medium-grained and the grain size is different here and diameter ranges between 2 to 1/16 of a millimeter. These are known as general rock rocks sand where it consists of a metal granules dominated by sand that comes influenced by factors of erosion, and the most important types of sand sandstone and sandstone limestone and sandstone limestone and sandstone rocks Iron.
3. Mechanical rocks upbringing fine grained, these rocks consist of finely divided diameter of no more than 1/16 mm. These granules are produced from the decomposition and fragmentation of metals, particularly metal silicates such as silicates and water ammonia can distinguish two types of these granules according to their size or two in diameter: silt or silt and Habibath relatively large diameter between 1/16 ranges to 1/256 mm and mud, which is a very fine granules diameter of no more than 1/256 mm was muddy rocks contain some residues decomposing organic matter such as humus, or the remnants of charred plants and the most important kinds of clay rocks are clay and stone clay and turns clay into mud stone when you lose the bulk of the water contents as a result of drought or increased pressure.
(B) chemical sedimentary rocks upbringing:
These rocks are formed by deposition of solutions containing dissolved substances, when the degree of concentration rise, according to natural circumstances surrounding it. Or it may consist of sediments as a result of a chemical reaction taking place between components of these solutions. You can distinguish the following types of these rocks on the basis of composition:
1. sedimentary rocks limestone: This consists of rocks as a result of the deposition of carbonate calcium from solutions limestone containing bicarbonate calcium dissolved from the rocks, limestone inorganic rock travertine (Travertine) and stone dolomite (Dolomite), which consists of calcium carbonate and carbonate Almoghaiseyoum different proportions.
2. sedimentary rocks Celikah: This consists of rocks from the deposition of the silica material such as flint (Flint) and this mixture of silica crystalline and amorphous be in the form of contract, as well as a stone-shirt (Chert), a type of rock Alcelikah is pure because they contain a high percentage of lime.
3. sedimentary rocks of salt: where the water evaporation from lakes and seas closed leads to the concentration of salt solutions in them and then deposited in the form of successive layers and the most important sedimentary rock salt is rock gypsum (Gypsum) and consists of this rock than a minute grains of water calcium sulfate, which are deposited in as layers or sheets and falls within this type as well as Anhaedraat rocks (Anhydrite) and deposited this last rock of the deposits of calcium sulfate anhydrous in addition to other salt rocks such as gypsum, table salt and rock salt.
(C) sedimentary rocks membership origination:
These rocks arise as a result of the accumulation or accumulation of the remains of plant and animal organisms (plant leaves and tree trunks and branches) after her death and shellfish and animal shells in the form of thick layers and then the decomposition of the remains is due to the effect of fungi and bacteria during a long period of time, then return these materials Vtaatmask with each other in body rocks as a result of pressure and smut, there are two types of rocks:
1. membership rocks animal: This consists of rocks from organic materials limestone Celikah or phosphatic such as limestone and organic the last rock is widespread consists of biodegradable peel and structures of marine animals, accumulating, called calcareous rocks as fossils which may be prevalent deployment, such as, limestone psoriatic type ( shelly Limestone).
2. vegetarian membership rocks: This produces rock for the accumulation of plant debris and then rot and decay and Tvhmha These are made from either Celikah materials or carbon materials, including the remnants of algae such as Diatom, and sediment carbonate latter consists result roasted marsh plants, ranging in carbon content of which from 55% to 72 Qatrani% and coal (bituminous coal) and Alantrasaat coal (Anthracite) and is considered the last of the stiffer coal types and the most quality and contains a high proportion of carbon material may be up to 98% of the total weight.
Sedimentary rocks structure:
Sedimentary rock structures can be divided into major structures include various types of sprains and fractures and systems spacers and heterogeneity, and the secondary structures are intersecting layers and crevices. It is rare that the sedimentary rocks in nature horizontally exist completely, the simple sedimentary area of any wrinkling leads to the formation of domes and basins ranging in size from a few miles to hundreds of miles away, or may increase it. Pressure in some cases may lead to the formation of twisting unusual and show the impact that ripples parallel alternate-shaped brackets and depressions called these brackets Balaltoaouat convex (Anticlines), while low ones authorities called twists concave (Syncline) It is rare that these distortions continue to infinity as they quickly Tstdq, ending, has Hafadtha appear on the surface of the earth in the form of afternoon (Strike).
Extreme pressure and may result in the magnitude of the refraction of torsion so composed after so-called refraction of the Reclining (Thrust Fault), and in the nature of the surface does not have such a refractive many away from the horizontal position after the adjournment so that became a look at the level of form Itagty sediment afterwards If formed a second series after that, the relationship between the two series of disparate smooth layers called the relationship a mismatch (Unounformity). And appear in some points of consensus are some clear differences in the angles that exist between rocks located upwards or downwards in the corner area layers. If the classes do not parallel shows a lack of compatibility, common for such a situation and the term is the lack of homogeneity (Disconformity).
Among the secondary structures that appear in the sedimentary rocks are also intersecting layers, cracked mud and various types of debris.
Second: igneous rocks:
Considered igneous origin rule for all types of rocks, producing these rocks to cool molten materials If cooled material magma on the surface of the earth, they constitute a solid surface If this article penetrated through other rocks and then cooled within the earth's crust, it is an object rocky internally. Igneous rocks clearly vary in terms of installed metal, chemical, textile and the way its presence in nature Vackor firearms interior can not Roetha only after the work of erosion on the removal of rocks located above factors, affects the installation of the rock fabric and the structure and shape of the Althatah forms which comprise it.
This magma may have in certain circumstances to climb into the depths of the earth's crust where rock interfere with constituents of this crust may sometimes reach the earth's surface. The exposed material magma in each case for these conditions to heat loss Vttjmd and crystallize either in the ground or on the surface: so divided igneous rocks according to the method of composition:
1. underground rocks include:
A - underground rocks.
B rocks under the surface.
2. superficial rocks (volcanic rocks).
The igneous rocks can be divided on the basis of mineral composition according to any material contained in the silicate rock to:
1. acidic rocks Acidic Rocks and these contain more than 66% of silicates low in iron and magnesium. So this is the color of the rock, opening, and examples of these Alkrani rocks and rocks and rocks Ablaat Alrajulaat.
2. Medium Intermediate Rocks silicate rocks found in these rocks by between 52% to 65% while increasing the proportion of iron and magnesium. It is color moderate but darkness most of the acidic rocks, and examples of these Aldajurajt rocks and rocks and rocks Andizeyt Trakait rocks.
3. basement rocks Basic Rocks silicate ratio and range in these rocks between 45% to 52% and, where abundant iron minerals Almgnesah ratio and have their color is usually bleak tends to blackness Examples of these rocks and gabbro rock basalt.
Igneous rocks structure:
In addition to the large blocs that appear out of igneous rocks in nature, there is also a small structures of these rocks affect the erosion landmarks that make up. As Faqrackor firearms to the regular order in which they appear in the sedimentary formations, where pressure and turbulence effect does not appear in igneous rocks in the form of quirks, but also in the form of breaks and breaks sometimes.
And be spacers more prevalent near the surface than it is deep in the crust as long as they are available to the rocks of a chance to stretch out on the surface impact of weathering forces, tend spacers in this party to be more casually looks so clear, although it continues inside the crust in the form of a few coherent structures appearing.
The forces that lead to the emergence of joints in igneous rocks include shrinking operations due to cooler firearms blocs and the process of expansion and contraction as a result of weathering processes resulting from the occurrence of additional jets of material Chihr, lava and pressure (Lava). Usually occurs spacers in the form of parallel groups and these groups usually intersect with each other at right angles are almost spacers and are very often in the form of distorted surfaces, for they may be in the big fireworks blocs heterogeneous curved or creased. Most of the spacers and take the form of vertically especially what the reason for their formation is due to movements in the earth's crust as well as a number of spacers take the form of horizontally.
The spacers are caused by contraction due to cold vertical situation on the cooling surface, so the intervals in this Anciabat lava vertical Guetaatha situation and this situation is the cause of the appearance of the vertical structure (Columnar Palisade Structure) present in basalt formations.
Filled with rock interludes sometimes metal material may work on the process of weathering resistance are stronger than the same rock. The show such veins or Sudaidat (Dikelets) in the form of ribs or small chains on the rocks exposed to the process of weathering surfaces. Most of the dams are also
We mentioned much stronger than interlaced with rocks, so they appear often in the form of walls and chains and hills irregularly when exposed to erosion.
Such fractures, like spacers, areas and surfaces weakness in the rocks. It is likely to be concentrated erosion along these surfaces are called valleys or depressions that follow fractures Lines spokeswoman Diane fracture line (Faultline faults) be such valleys straight over long distances and communicate with their tributaries angles are almost due to cross spacers pattern, and in fact can be traced watery discharge pattern angled in bodies where igneous rocks spread to the existence of an elaborate system of fractures and joints are.
Third: The metamorphic rocks:
Metamorphic rocks form the third type of rocks and these igneous or sedimentary in origin transformed by pressure and heat, or as a result nominate other materials so still the original characteristics of the rocks and referred to them by another Properties. And appear in most of the metamorphic rocks crystalline structure, as some are very resistant to the processes of weathering and erosion. That changes in the temperature and pressure changes, or both, often lead to a change in the original tissue type rock or mineral composition, also it helps the presence of water or aqueous solutions in general to complete this process of transformation. There are many types of transformation are:
1. Pyrolysis or dermatitis Thermal or Contact Metamorphism
This transformation occurs in the immediate vicinity of or adjacent to the material magma and this limited area locally known as loop transformation (Metamorphysic role) so you may know this transformation as the local switch (Local metamorphism)
2. Topical shift or shift change the situation: where the high pressure leads to change or relatively slight shift in the positional rocks on both sides of fractures or cracks resulting from this pressure.
3. The regional shift or dynamic transformation:
(Regional metamorphism or dynamic metamorphism) and
High pressure accompanied leads at high temperatures and resulting from crustal movements to a large-scale shift extends in large regions and large areas.
Thermal switch to the formation of metamorphic rocks out may lead sedimentary sand as in the quartzite rock, which consists of turning the sandstone, or lead to the formation of metamorphic rocks out of sedimentary mud as is the case in rock Alhornvels, and produced the last of the thermal transformation of rocks mud and clay . This shift may lead to the formation of metamorphic rocks out Jerry as is the case in the marble be as pure limestone rocks turn into white marble with color Mozaiecki tissue. The impact of the transition has been much to the point disappear with the original rock landmarks just as disintegrate the original or rocks may melt and melt then regain its existence again shall be amorphous and arranged so that results from this arrangement gathering of metals in the form of thin layers or strips (Bands) or papers (Folia) or pages (Laminate) parallel and perpendicular to the direction of pressure. And described the rock fabric then he striping (Banded Texture) or paper (Foliate) or slate (Laminate) of the most important types of metamorphic pressure and heat, the rocks are slate (Slate) This rock mutant child sedimentary rocks as a result of high pressure and relatively low temperature. These rocks are also rock Alnaess a rock mutant out of this fiery rock consists of a large amorphous matrix arranged in the form of granules thick strips may be intermittent or lenticular.
Rock vulnerability factors:
Rocks can be classified into weak Soft rocks such as chalk, clay and sandstone - and rock solid Resistant \ Hard rocks such as granite and basalt rock and flint. This classification is based on the extent to which the rock weathering and erosion processes scratching or different and demolition. The rocks are quick decay and disintegration and erosion weak rocks, while untold rocks that are resistant to these processes and maintain the original status of the forms the ground for the longest possible period of solid rocks. It may be weak or solid rock originally due to natural or chemical characteristics, as the rock may be exposed to weaken or sclerosis due to environmental conditions or factors affecting geomorphological. So, it can distinguish between three groups of rock vulnerability factors:
First: the qualitative aspects of vulnerability:
It started with Tnchae rock, itself the result of the way or created the conditions. So that they can inherit the rock acratia because of the quality of the minerals that compose it, and the degree of crystallized or strong Texture or porosity Porosity or color, or because of a carnivorous materials Cementing material that collects and Mineral them clumping granules, the following are the most important specific characteristics of the specific weakness of the rock:
1. Chemical composition:
Chemical composition of the rock an important role to play in hardness or weakness through the minerals and elements of chemical constituent ratios, which can be determined by Moh hardness Mohs scale of hardness scale, and is a diamond in the roughest kinds of minerals scale while metals gypsum represent and lime slightest rigidity.
