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[en] Multi-model frameworks are widely used to identify the appropriate model structure for the study catchment. However, most frameworks mainly consider the process complexity of the model, and few of them consider the spatial complexity. In this paper, we investigated the appropriate model structure for a karst catchment from the aspect of spatial complexity. The purpose is twofold: (1) to investigate whether the spatial complexity is needed to simulate the spring discharge of this karst catchment and (2) to investigate whether the increase of model’s spatial complexity can make up its deficiency on the process complexity. Three simple lumped models with different process complexities were chosen to gradually increase the spatial heterogeneity of their parameters to investigate the appropriate model structure for simulating the discharge of a karst spring. The results show that the performances of three lumped models highly improve when adding the routing function to them. However, further considering the spatial parameter heterogeneity, only one model shows obvious performance improvement and other two models show limited improvement. Moreover, this model with relatively complex spatial parameter heterogeneity still shows worse performance than another lumped model. This indicates an increase of models’ spatial complexity cannot always make up their process deficiencies. The final comparison results indicated that the lumped model or their semi-lumped version with flexible process complexity is enough to simulate the discharge of this karst spring and no extra spatial complexity is needed. Our studies also indicated that the increase in spatial complexity of the model cannot always fully compensate its deficiency in process complexity.
[en] This study is about the western edge deposits belong to Lavalleja group locataed in the proximity of the Sierra Animas formation. The rocks dominants In this zone are phyllite, calcareous phyllite and limestone magnesian, usually grey or black denoting environment reduce
[en] The Research has been carried out at geothermal Regional using 2d resistivity imaging and Gemagnetic method in Dusun Silou Kahean Subdistrict, Kabupaten Simalungun. The purpose of this study is to determine the distribution of earth magnetic anomalies, rock structures, and fluid distribution patterns. The measurement of geomagnetic method uses PPM (Proton Precession Magnetometer) type Elsec 770. Data retrieval have been done randomly with the number of points obtained by 40 measuring points, the data is processing by using surfer 10 to determine the contours and Mag2DC to obtain a magnetic anomaly cross section. The 2D resistivity imaging is used to determine the rock resistivity value. The results showed that the anomaly value with the geomagnetic method had the lowest value of 20.51 nT and the highest value of 67.18 nT. The susceptibility value of 0.00051 to 0,00098 cgs is indicated by sandstone and susceptibility value of 0.0013 to 0.0016 cgs is indicated by limestone. The 2D Resistivity imaging method has a resistivity value of 12.5 to 37.3 Ωm is indicated by Silts layer with a depth of 1.25-3.75 meters, and a resistivity value of 1.26 to 8.72 Ωm is indicated by c lay layer with a depth of 6.38-12.4 meters . from the results it can be concluded that the fluid dispersion contour using geomagnetic and geoelectric methods is spread across from the southwest to the northeast. (paper)
[en] The MTT (Mean Transit Time) of a catchment without significant surface flow is normally taken to be the sum of mean residence time in the unsaturated zone and mean residence time in the saturated zone. However, the Chalk is a multi-porosity limestone aquifer, with a microporous matrix. This means that the movement of water through the Chalk can occur in complex ways, making the prediction of MTT far from straightforward. Although the Chalk is a regionally-important aquifer, no study of catchment MTT has yet been published. The present study is based on the catchment of the River Lambourn in Berkshire, UK, with an area of 235 km2. Interfluve areas rarely rise above 200 m asl (above sea level), whereas river elevation at the foot of the catchment is ∼50 m asl. Mean annual precipitation is 731 mm. The thickness of the Chalk unsaturated zone reaches a maximum of over 100 m at the water divide at the top of the escarpment on the northern flank of the catchment.
[en] This work brings information of fields and laboratory samples about the outcrop in Treinta y Tres district in the framework of limestones programme carried out jointly with I.G.U and BGR through the geological German mission
[en] The effect of a dispersed mineral additive (limestone) on the structure and the strength of hardened cement paste was investigated. It was shown that a dispersed mineral admixture significantly influences on the hardening of cement paste. To obtain the maximum strength, the optimum quantity of additive is 7%, it gives an increase in the strength of hardened cement paste by 22%. It was shown that when the limestone is added, there are significant changes in the structure of hardened cement paste. The number of pores with a diameter less than 1.2 microns increases, the total pore volume and the total pore surface also increase. This enlarges the characteristic length of pores and reduces the tortuosity of pores. In a cement paste with no admixtures, the structure is loose enough, with a large number of shrinkage pores with a size of up to 0.05 mm. The hardened cement paste with admixed dispersed limestone has a denser, more homogeneous fine-crystalline structure with a small quantity of pores in all investigated periods of hardening. (paper)
[en] In this paper, the sedimentary, geochemical and coal petrographic characteristics of the Upper Paleozoic Taiyuan and Shanxi Formations in Huanghua Depression are systematically analyzed. It is found that the formation process of Taiyuan Formation coal seam is greatly influenced by sea water. The overlapping relationship between limestone and its floor rock is a typical progressive transgressive sedimentary type. Geochemical data show that the limestone roof and floor strata are also formed in high salinity sedimentary environment, similar to the limestone development environment, which also shows that the transgression process in the study area is gradual, not sudden transgression. (paper)