Hydrochemistry and environmental isotopes (18O, 2H, 3H, 3He/4He) of groundwater and floodwater in the great area of Hurghada, Eastern Desert of Egypt

Porous and fractured aquifers exist in the area of Hurghada, Eastern Desert of Egypt, whose recharge processes through the common flash floods are not identified. Hydrochemical parameters, stable isotopes 18O, 2H and tritium in floodwater and groundwater were applied in the area subject to study. Additionally, He isotopes were investigated in the deep wells in the faulted zone at the Abu Shaar Plateau. 3H activity in all sampled points lies below the detection limit excluding a recent recharge component in groundwater. However, the hydrochemical ratios and the stable isotope signature confirm that the shallow wells and springs (Red Sea Hills group) are being recharged from modern precipitation. The hydrochemical parameters of the deep wells at the Abu Shaar Plateau (coastal plain group) confirm another origin for the ions rather than the modern precipitation. Together with the 18O and 2H values, the Br/Cl ratio of this group confirms the absence of seawater intrusion component and the role of the fault as a hydraulic barrier. These 18O and 2H values deviate from the GMWL confirming an evaporation effect and colder infiltration conditions and reveal strongly a possible mixing with the Nubian Sandstone in the region. The 3He/4He ratio confirms a mantle contribution of 2% from the total He components.

The Kasterlee Formation and its relation with the Diest and Mol Formations in the Belgian Campine

Stratigraphic analysis of cored and geophysically logged boreholes in the Kasterlee-Geel-Retie-Mol-Dessel area of the Belgian Campine has established the presence of two lithostratigraphic units between the classical Diest and Mol Formations, geometrically related to the type Kasterlee Sand occurring west of the Kasterlee village and the study area. A lower ‘clayey Kasterlee’ unit, equivalent to the lithology occurring at the top of the Beerzel and Heist-op-den-Berg hills, systematically occurs to the east of the Kasterlee village. An overlying unit has a pale colour making it lithostratigraphically comparable to Mol Sand although its fine grain size, traces of glauconite and geometrical position have traditionally led stratigraphers to consider it as a lateral variety of the type Kasterlee Sand; it has been named the ‘lower Mol’ or ‘Kasterlee-sensu-Gulinck’ unit in this study. In the present analysis, the greenish glauconitic Kasterlee Sand in its hilly stratotype area evolves eastwards into the lower ‘clayey Kasterlee’ unit and possibly also into an overlying ‘lower Mol’ or ‘Kasterlee-sensu-Gulinck’ unit, although it is equally possible that the latter unit has an erosive contact and therefore is stratigraphically slightly younger than the type Kasterlee Sand west of the Kasterlee village. A lateral extension of this detailed stratigraphic succession into the faulted zone of east Limburg is proposed.

Fracture characteristics of Lower Carboniferous carbonates in northern Belgium based on FMI log analyses

Recently drilled geothermal boreholes in Mol, northern Belgium, provide new information on the Lower Carboniferous carbonates in the Campine–Brabant Basin. Because of low primary porosity, fractures in these limestones and dolostones are of major importance for reservoir permeability. The Fullbore Formation MicroImager (FMI) log of the MOL-GT-01 borehole enabled interpretation of bed boundaries and fractures in the subsurface. Relationships between the frequency of these fractures and bed thickness, lithology variations and the presence of faults were explored. The results show that thick beds contain relatively few fractures and thin beds relatively many. Except for lower values in shaly intervals, the fracture frequency (number per metre) is largely independent of lithology. Zones with substantial changes in the structural dip (called a cusp) and/or azimuth of bed boundaries were identified. The clearest cusp is present at a depth of 3284 m. Since the presence of a normal fault is most likely regarding the local and regional geology, this cusp likely resembles a fault-tip fold of a WSW-ward dipping normal fault with an inclination of at least 54°. It is uncertain whether the borehole crossed the fault itself or only a monocline on top of it. Fracture frequency is increased in the vicinity of the interpreted possible faults. Up to a vertical distance of c.45 m from the faults, the mean fracture frequency is higher than in a non-faulted zone with similar lithology. However, frequency differences between these faulted and non-faulted zones are mostly insignificant, so no clear damage zones are present.

The Stability and Management of “Sandwich” Type Slopes in Extrusive Rock Area

Northern area of Hainan Island is located in the south of Leiqiong faulted zone; new tectonic movement and volcanic activity have intense since late tertiary. Cenozoic volcano in the region is developed, various types of extrusive rocks widely distributed which often directly cumulate on the Cenozoic sedimentary soil layers, then covered by more loose soil, form a soft - hard - soft “sandwich” type slope with a poor stability. Based on the study of this slope and simulate its stability, this paper proposed this kind of slope's destruction mechanism as well as the management method

Deformation Simulation of Surrounding Rock at Faulted Zone during Roadway Drivage

Sometimes transportation roadways needed to go through the water-conducted normal fault with high dip and big fault throw in order to ensure the mining continuance, the two key factors were fault water and deformation of surrounding rock which influenced the digging safety and stabilization of roadways. On the base of analyzing clearly the FB11fault in 2ndsubterranean mine, pingshuo diggings, the fault water was drained and COMSOL Multiphysics software was used to simulate deformation and destruction of the surrounding rock. The following conclusions were drew that larger amount of deformation and destruction caused in single roadway than double roadway drivage, The deformation in soft surrounding rock was larger than in hard rock, the fault had more influence on soft surrounding rock than hard layer. the fault made the plastic area extend to the whole fault belt, The above conclusions were confirmed by the following drivage project .