الفهرس 
LITHOSTRATIGRAPHYOnly 14 pages are availabe for public view
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Abstract
Eight sections were measured and described in the Marsa Matruh shoreline (coast). These sections are Agiba, Romel, Alam El Rum1, 2 and 3, Cleopatra road area, beach rock and costal rock boulder. Several features and observations were recorded. Among these are elevations, bedding, lamination, cross bedding and texture.
The litostratigraphy of the study area belongs to the Quaternary (Pleistocene and Holocene) and Tertiary (Miocene and Pliocene). Agiba lithostratigraphic section belongs to Miocene- Pleistocene, Romel and Alam El Rum belong to Middle Pleistocene, whereas Cleopatra area belongs to Holocene.
The quantitative and qualitative determination of the grain size frequency distribution of the Quaternary sediments in Romel and Alam El Rum and Fore dune Cleopatra area are analyzed and measured. Alam El Rum 1 of middle Pleistocene ridge is characterized by medium moderately sorted sand. Alam El Rum 2 of Pleistocene ridge is characterized by medium moderately sorted sand. Alam El Rum 3 ridge is characterized by coarse moderately well sorted sand.
Romel Pleistocene ridge is characterized by medium moderately sorted sand. Cleopatra Holocene Fore dune is characterized by medium moderately well sorted sand.
Geochemical analysis of Alam El Rum and Romel ridge and boulder shows that the dominant cements precipitated in this environment are low Mg – calcite and aragonite.
Petrographical investigation focus on detailed description of rocks components, textures and mineralogy.
27 thin section samples investigated under Olympus Polarizer Microscope proved that there are two main types of cements which are:
1- Meniscus: If pore water is distributed between the grains. In which cementation may occur in the lower part of the vadose zone; the cement morphology tends to reflect the distribution of the pore waters indicating fresh water vadose zone.
2- Isopachous: If a thin crust of small crystals can be seen on all grains surface indicates active marine phreatic zone.
These cements are formed on marine beaches by fibrous aragonite and micritic or fibrous Mg-calcite. Mg – calcite cement forms isopachous crusts on the grains, consisting of micritic or steep – sided rhombic crystals. Marine aragonite cement is typically present as fibrous crystals in a variety of textures, which may be caused by the substrate on which the cementation takes place, the nature of the cavity and the rate of crystallization as present in beach rock samples.
Two main types of porosity are recorded which are intergranular and vuggy porosity indicating shallow and marginal marine environments.
In supratidal and intertidal environments porosity is often plugged by secondary anhydrite cement. Leaching of gypsum or anhydrite by freshwater may produce moldic, vuggy and breccia porosity.
Porosity in nonreefal carbonate shelf environments may be distinctly controlled by the original depositional fabric of the sediment. Five main types of porosity were recognized, including intragranular, intergranular, leached skeletal, leached micrite and dolomite vuggy porosity. Shallow marine environment (subtidal) below the tidal zone sometimes directly adjoining the supratitdal area.
The neomorphism, which has recognized is of aggrading type, leading to the enlargement of crystal sizes as shown in samples. It is represented by:
1- Replacement of the calcareous particles by pseudosparite.
2- Recrystallization of the micrite matrix and the fibrous calcite of the isopachous cements.
Neomorphic replacement of cements and skeletal materials is thought to be proceeded by a thin solution film mechanism, whereby a fluid film less than a few microns thick moves through the grain boundaries or cement, dissolving the carbonate (usually aragonite) in front and precipitating calcite behind.
Aragonite and high Mg-calcite are favoured by warmer temperatures, while low Mg-calcite and calcite preferentially form at colder temperatures.
X-ray diffraction analysis of the Romel ridge samples reveals that the common carbonate minerals detected are magnesium calcite and aragonite but the amount of aragonite is greater than the amount of magnesium calcite. The X-ray diffraction data of the Romel boulder samples consist of less aragonite than the Romel ridge but don’t contain magnesium calcite indicate recent environment in addition to halite due to weathering.
X-ray diffraction analyses of Alam El Rum ridge to Alam El Rum boulder samples show decrease in the percent of aragonite and relatively increase in the magnesium calcite content. The decrease in aragonitic content is may be due to rarity of aragonitic allochems (ooids) and increasing of the calcitic bioclasts and intraclasts. The X-ray diffraction data have shown halite as weathering product.
The carbonate contents of section romel have average 100%, the samples of section Alam El Rum have average 100%.
Most of coastal boulder of Romel, Alam El Rum 1, 2 and 3 are bladed to disc shape .Geological evidence for past and historically undocumented giant wave events in the form of boulder fields and coastal debris ridges, has been recorded from four locations (three from Alam El Rum and one from Romel ) on the coatlines of Marsa Matruh. The sites occur on the Pleistocene ridges (terraces ), at heights of up to averaging 21 m in Alam El Rum and 7.5 m in Romel asL and face zones where deep water relatively close inshore. Boulder lithologies closely resemble that of the platforms on which they rest and they appear to have been torn from the front of the platforms and transported to their present locations by giant waves. The waves may have been caused by storm surge and waves from very powerful hurricanes, or from the large waves generated by tsunami (often and incorrectly called tidal waves).
C14 age dating isotope for two samples are carried out at French institute (Imhotep 2015) calculated as:
1- LIA (Little Ice age) storms and a well –recorded 1303 AD paleo-tsunami in dating boulders (attatched fossils).
2- A Glycemris mollusk collected from an old beachrock unit at +20m above current MSL yielded an age of 71.800±5.700 applying ESR (Electron Spin Resonance).
This study recommended that the most hazardeous coastal sites in Matruh are
-To avoid the housing and the problems resulting for constructing tourist villages along the shoreline in these areas.
-These sites (Alam El Rum) are best sites to generate electricity from strong sea waves and storms.