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جيومورفولجية المراوح الفيضية بين النجف والسماوة

جيومورفولجية المراوح الفيضية

بين النجف والسماوة




رسالة تقدمت بها

جميلة فاخر محمد



إلى مجلس كلية التربقية للبنات - جامعة بغداد 

وهي جزء من متطلبات نيل درجة الماجستير في الجغرافية



إشراف

الأستاذ المساعد الدكتور

أسحق صالح العكام



1437هـ - 2016م





Abstract:

  Alluvial fans are one of the most prominent features of water dry deposition in the dry areas and semi dry .It is point of separation between the nature of the center flow within the drainage basin runoff which spread easily on the environment of sedimentation.

   The study of Alluvial fans concentration two directions, the first direction, a unit geomorphology stand-alone, with characteristics that distinguish the fan floodplains from the rest of the units basin water drainage through the study of the mechanism of formation, growth, the factors affecting it, the characteristics and environmental features, geomorphological processes that take place over it. The other flooded trend was the study of alluvial fans as part of the flooded integrated that is influenced by processes that take place with full parts of the basin, where the reached inputs affect geomorphological processes that occur on the surface of the bason . Their effects are shown the show on all parts of the basin, including the alluvial fan.

    The study consists of six Alluvial fans with the drainage basins .It contains extends in most AL-Najaf plateau and parts of the provinces of Al-Diwaniya and AL-Muthanna. The extends between (29.49-32.9)North Latitudes and between (42.29-45.1)east Longitudes . The study area Occupyies (23155)km2 of the surface area of Iraq .It Occupyed and of Alluvial fans(156.1)km2, of basins (22998.9)km2of the regions of the whole area . It takes general trend to the north –east.

  The emergence of depositions Aluvial fans at the end of the mouths of canyons, where these sediments formed space (156.1 km 2), with arate (0.67%) from the area configurations of the area . It is a sign of the accompanied consecutive the periods of deposition and erosion by changes in the time Al-Blallostosen changes, these formations have continued in the deposition until the time of the Holocene ,it was reached to form Aluvial fans by comparing the geometry, the same model figure fans have included fans (Alkur, Abu doab, Abu Shinan). The fans that have a triangle shaped They include Two fans (hasap, Alheiazi), whereas Valley Faraj fan, has approached an abnormal, it was concluded shape or (semi- turbofan). It was concluded applying Milton coefficient, and the coefficient of the relationship between sculpture and deposition rate (R) fans the study area, that the fans have reached an advanced Anah stage of the surface construction. It has begun to move from construction to demolition, was conducted laboratory quantitative analysis of the sizes of the surface sediments, where it has (18) sample rate (3) samples of each fan, was reached through the analysis that the large-scale sediment was Arsabha at the scope of fans flood peaks. It appeared that the gravels more types sediments prevalent in the tops of the fans .As for results of the analysis of deposits amid fans have shown the rule of medium sand, have shown results deposits feet fans sovereignty deposits silt and clay analysis, thus clearly included in the sediment volumes across its parts has emerged.

    A morphological analysis of surface deposits was conducted that exceed the size (2 mm), where pebbles were analyzed (324) pebble, has been reached to the high proportion of gravel round and a good rotation rate (26.67%, 28.15%) in samples amid fans, it has been adopted method ( Krombaan) in the extraction spherical surface sediments, where it became clear which spherical sediments high in general, it has reached a spherical proportion of deposits peaks fans flood was (0.68%) where the deposits amid fans spherical sediments reached (0.73%), were the forms of sediments depending to (Zingg s classification was reached through it to the sharp form (roofing) is the dominant form of grit fans tops .It show that the average rate of (43.78%) of the percentage of forms of gravel in the fans tops, is a square shape is the dominant form in deposits amid fans flood, where the rate stood at an average (37.04%) of the percentage of forms gravel deposits in the center of the fans, Has been reached to the degree of risk of floods is possible that occur on the surface of the fans, were divided into three levels, and these levels varied in the spaces within the fans, reaching high-risk area of land (57.13 km2), and by (36.6%) of the total fan area , while the medium-risk land area (52.17 km 2) and by (33.42%), while the few dangerous land area has reached (46.8 km 2) and by (29.98%) It was reached classification of land use and land cover in the fans flood relying on the US Geological System (U.S.G.S) by drawing classification maps for uses of Alluvial fans, and the field study of these fans, where the uses were identified land down to the third level of the surface of fans.


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