Iranian Journal of Earth Sciences
Volume:12 Issue: 3, Jul 2020

The aim of this study is to estimate runoff in Wadi Ba Al Arid watershed for a period of ten years 2009-2018 by Soil Conservation Service Curve Number (SCS-CN) method in combination with the GIS techniques using remote sensing data. The used data are the daily rainfall data from NASA Prediction of Worldwide Energy Resource (POWER), digital elevation data (DEM) from ALOS PALSAR RTC , satellite imagery from the European Space Agency (ESA) Sentinel, and soil data represented in soil maps of a scale 1: 50,000 and some local studies carried out  by several Libyan institutions. The overall area of the watershed is about 136.4 km2 and perimeter107.3 Km. The watershed upstream and downstream is well recognized due to the topographical difference as a result of the tectonic geology. Soil maps were processed and classified into hydrologic soil groups (HSG), where the dominant HSG in the study area are C and D. The Landcover/Land use (LULC) was classified into five classes (forest, shrubs, agriculture, barren land) and built up. The HSG and LULC layers were intersected and the CN values and the weighted curve number for each Antecedent Moisture (AMC) condition were assigned. Furthermore, the runoff depth was estimated and the average runoff volume for ten years during 2009–2018 in the study area was estimated by 1.67 Mm3 which represents 4.6 % of the observed average annual rainfall as 264.3 mm during 2009-2018. The rainfall-runoff relationship has shown a strong correlation with the value of 0.75.

Geomagnetic study was carried out to investigate the distribution and depth of formations of different magnetic rocks on an old quarry site, Abeokuta, Southwestern, Nigeria. Eight ground magnetic profiles were established with 10 m spacing intervals orientated in West-East and North-South directions, and ranged between 110 and 190 m. A total of 223 data sets were acquired and corrected for all forms of magnetic variations. The resulting residual anomalies were plotted against distance using Microsoft Excel tool. Also, these anomalies were modeled into 2D and 3D contour sections using Surfer 10. The depth to basement analysis was carried out using Peter’s half slope graphical method. The resulting profiles and contour sections revealed variable anomalies which indicated contrast in the magnetic distributions of the subsurface. Mineral rocks with average (0-150 nT) magnetic susceptibilities dominated the profiles, and this indicated that the study area is on pegmatite or Quartz vein which probably harbored Beryl, Graphite, Sandstone, Quartz, Tantalite and Mica in both massive and disseminated quantities. Regions with high (150-300 nT) and low (0 to -150 nT) magnetic susceptibilities were also observed across the profiles. Mineral rocks with very thin bodies were observed at depths 3.48-17.42 m, intermediate bodies were buried at depths 2.61-13.06 m, while very thick bodies were located at depths between 2.09 and 10.45 m. The depth of the magnetic sources revealed that the major and minor mineral rock contact in the study area.

The Gurpi, Tarbur and Sachun formations have been investigated in the studied section in the Fars Province, in order to determine their sequence stratigraphy. On the basis of done studies on the cores of borehole, four main microfacies have been recognized in four stratigraphic sequence deposited during the Campanian to Maastrichtian. The lowermost sequence, was deposited in the early Campanian-early late Campanian which include wackestone to packestone texture with Globotruncanita elevata Zoneand Globotruncana ventricosa Zonethatrepresentative of the deep marine and outer ramp. The intermediate and uppermost sequences (sequences two, three and four) display well developed deposits formed in the end of the Campanian (Radotruncana calcarata Zoneand Globotruncanella havanensis Zone), formed during the Maastrichtian (Globotruncana aegyptiaca Zoneand Gansserina gansseri Zone) and the end of the Maastrichtian (Omphalocyclus macroporus - loftusia sp assemblage Zone) on pelagic, hemipelagic, outer and middle ramp. On the basis of the sequence stratigraphic chart, the transgression of the upper Cretaceous sea started since the early Campanian and continued gradually until the early Maastrichtian. Then, until the end of Maastrichtian, the area has been emerged. The sequence stratigraphic architecture of Campanian/ Maastrichtian Gurpi, Tarbur and Sachun formations model is in a good agreement with global sea level changes.

There are several phenomenons for polluting the environment, especially in coalfields; which coal spontaneous combustion is one of them. The moisture content is one of the intrinsic characteristics of coal, which has an important role in the occurrence of this phenomenon. Therefore, this research predicts the coal spontaneous combustion tendency based on moisture content. The percentage of moisture content is a very important parameter on the occurrence of this process; so far a conclusion about the effect of moisture content on coal spontaneous combustion, a comprehensive study was done. 55 coal samples with different percentage of moisture content for the training of overall underground coalfields in Iran were collected and the CPT test method for each coal sample was carried out. Then, the method of regression analysis was used for modeling and predicting the coal spontaneous combustion tendency. The results show, the coal sample undergoes oxidation most rapidly when the moisture content supply is about under 20%, and it can reduce coal spontaneous combustion in excessed of 20%, because when moisture is present in excessed of 20%, the heat released by oxidation is used to evaporate the moisture. For validation and testing, 15 coal samples of another coalfield were collected and the CPT test method for each coal sample was carried out, and the results of the test method were compared by the regression equation. The results obtained from the models show that a good appropriate prediction has been done for determining the coal spontaneous combustion tendency by regression analysis.

The image logs interpretation from two wells in a fold hosting a west Iranian oil field located in the Dezful Embayment, SW Iran reveal the occurrence of two major systems of natural fractures. In the central part of the fold, the fold-related fractures include two sets of fractures trending N53°E and N34°E. In the eastern and also curved part of the fold, the strike of open fractures varies from N85°E to S85°W with average dip of 63 degrees. Due to operation of the sinistral strike-slip fault, an anticlockwise deflection of fold axis was occurred, which caused to change the orientation and density of fractures in the curved part of the fold. Based on the orientation of the induced fractures and borehole breakouts, the mean present-day maximum horizontal stress orientations varies from N55°E to N30°E in the central and eastern parts of the fold. The SHmax orientations observed in wells located in the eastern and central parts of the fold are nearly consistent with SHmax orientations derived from nearby earthquake focal mechanism solutions and also with the absolute plate motion direction of the Arabian plate in the Dezful Embayment. Due to reactivation of the NE–SW oriented strike–slip faults, the mean shortening direction in the Zagros folds and thrust belt can be changed in the south Dezful Embayment. Drilling of production wells that are highly-deviated or horizontal and oriented approximately towards the present-day stress SHmax are likely to both intersect more hydraulically conductive fractures and reduce wellbore instability problems.

The Kordkanlo Basin, one of the Atrak sub-basins, located in the northeastern of the Ghoochan city, the Khorasan Razavi Province; is situated in Kopet Dagh geologic zone. The overall objective of this study is to evaluate the morphotectonic effects on the drainage network of the basin, using morphometric indicators. In this research, morphometric quantitative indicators of hypsometric integral (H), the ratio of the valley area to the an area of half-circle with a radius equal to the valley depth (V), the ratio of the width of valley floor to a height of the river (VF), asymmetry factor (AF), the river’s length gradient index (SL), transverse topography symmetry factor (T) and index of mountain front sinuosity (SMF), the basin shape index (BS) and the index of (Lat) have been used. This purpose tries to identify the role of change in lithological and tectonic agents on the Kordkanlo river basin using topographic maps, digital elevation model (DEM) and the information obtained in the field survey. In this context, ArcGIS software has been used for determining geomorphic indicators to determine the tectonic characteristics of the basin. Finally, index values were evaluated by the lat index. The result reveals high tectonic activity in the study area.