الخصائص النسيجية و الجيوكيميائية لرسوبيات خزانات المياه الجوفية في منطقة غرب مكحول، العراق

الملخص EN

The study area is located to the west of makhul hills between north of baiji city and south of sharqat city covering a total area of about 526 km2.

two wells have been sampled in the present study by taking one sample at (1-2) m.

interval.

a total of 19 samples were collected (13 samples from the first well and 6 samples from the second well), taking into account the lithological variations during the drilling process.

the samples were characterized as clastic (sand and mud) brown in color and friable.

the grain size analysis processes, using dry and wet sieving, revealed that samples of the first well can be classified as sandy mud and mud, while the second well samples are classified as sandy mud, and sandy silt.

the sedimentary facies were described according to their fabric and lithology and found that the majority belong to the injana formation and quaternary sediments, occurring in the southwestern part of the area.

the order and overlap of these facies in lenses has led to the formation of multi aquifers.

the presence of sand layers, with high connected porosity, has enhanced the hydraulic characteristics, and therefore, they worked as aquifer beds or host of ground water.

the grain-size cumulative curves showed that the sediments were transported by saltation and suspension which are common mechanics of transportation in fluvial environment.

the cumulative curves show a unimodal distribution, which indicates lack of changes in sedimentary environment during deposition.

a bimodal distribution was noticed in some samples, whereas limited multi-distribution (polymodal) was found in some samples from the first well, which indicates lack of regularity in the transport energy and result in grain size variation.

the chemical properties of the water extracts from the sediments indicate an increase in salinity and calcium concentration at the upper parts due to evaporation with increasing concentrations of organic matter due to human activity.

neutral ph was found throughout the section of the well.