Examining Thermodynamic Changes During Soil Moisture Loss

Geotechnical and Geological Engineering - Distribution constant, (Kc) is employed to account for desorption of water molecules from soil particles. When water molecules have strong affinity for...     

On the variability of the position of the equatorial electrojet axis in India

An examination of day-to-day and monthly mean positions of the electrojet axis in relation to the changes in the apparent solar declination, in the Indian equatorial region shows marked association between the two. For relatively quiet days, significant correlations are observed between the solar declination and each of the parameters, the northernSq focal latitude, the jet axis and the line of maximumSq(H). From the significant mutual association of these parameters, it has been suggested that the equatorial electrojet could be a part of the world-wideSq current system.     

Isotopic composition of xenon in petroleum from the shell bullwinkle field

We have measured the abundance and isotopic composition of xenon in petroleum samples from the Shell Bullwinkle Field off the coast of Louisiana. We used an oxidation and purification procedure designed to insure complete extraction and clean up of xenon from the petroleum. The xenon isotopic composition was found to be similar to the atmospheric value for one petroleum sample. While the results of the second sample suggest possible enrichment of the heavier isotopes, the errors associated with these excesses preclude a definitive statement to that effect. No monoisotopic enrichment in¹²⁹Xe was detected in either sample, the presence of which might have allowed us to deduce the petroleum age. Our results represent only the second xenon measurement from petroleum, and the concentrations are within the range of values published in the earlier report.     

Groundwater targeting in a hard-rock terrain using fracture-pattern modeling, Niva River basin, Andhra Pradesh, India

In hard-rock terrain, due to the lack of primary porosity in the bedrock, joints, fault zones, and weathered zones are the sources for groundwater occurrence and movement. To study the groundwater potential in the hard-rock terrain and drought-prone area in the Niva River basin, southern Andhra Pradesh state, India, Landsat 5 photographic data were used to prepare an integrated hydrogeomorphology map. Larsson's integrated deformation model was applied to identify the various fracture systems, to pinpoint those younger tensile fracture sets that are the main groundwater reservoirs, and to understand the importance of fracture density in groundwater prospecting. N35°–55°E fractures were identified as tensile and N35°–55°W fractures as both tensile and shear in the study area. Apparently, these fractures are the youngest open fractures. Wherever N35°–55°E and N35°–55°W fracture densities are high, weathered-zone thickness is greater, water-table fluctuations are small, and well yields are high. Groundwater-potential zones were delineated and classified as very good, good to very good, moderate to good, and poor. Electronic Publication     

滇西菲红超基性岩风化壳铂族元素地球化学行为

近年来在世界不同地区进行了风化过程中铂族元素的地球化学行为研究。作为中国西南部的第一个实例，本文研究了云南西部菲红超基性岩体上发育的红土风化剖面。矿物学和微量元素地球化学研究证明该风化壳是超基性岩风化的结果。文中详细讨论了风化壳的地质、矿物学、红土化和铂族元素地球化学特征。结果表明，风化壳的红土化程度不高，仍处于红色粘土阶段；风化壳上部的表层土壤带和铁质粘土带中铂族元素总量至少富集了3．57－7．87倍，其中Ru和Pd的富集程度较大,Ir的富集程度中等，Pt和Rh的富集程度较小，使得铂族元素的配分模式由基岩的Pt富集型转变为风化壳的Ru-Pt富集型，证明红土化过程中铂族元素发生了分异。     

The value ofC efor the Arabian Sea during summer monsoon

We estimate, from the moisture budget the bulk aerodynamic coefficient for latent heat flux (C _e) during the monsoon season over the central Arabian Sea. The average value ofC _eunder active monsoon conditions was found to be 2.25 × 10⁻³ which is nearly 60% higher than those previously used.     

Crustal structure from deep seismic soundings along the Koyna II (Kelsi-Loni) profile in the Deccan Trap area, India

The crustal depth section obtained from deep seismic soundings along the Koyna II (Kelsi-Loni) profile, which lies near latitude 18°N roughly in the east-west direction in that part of the Deccan Trap Maharashtra State, India, shows a number of reflection segments below the Deccan Traps down to the Moho discontinuity. A deep fault below the Deccan Traps 13 km east of Mahad divides the entire cross-section including the Moho boundary into two crustal blocks. The reflection segments show updip towards the west coast in the western block. The Moho discontinuity which is at a depth of 39 km near the deep fault starts rising towards the coast, reaching a depth of 31.5 km at the west coast. The eastern block is thrown up by 1.5 km with respect to the western block along the deep fault. A structural contour map of the Moho discontinuity for the Koyna reservoir area has been prepared from the present results and the crustal information obtained along the Koyna I profile (Kaila et al., 1979a), shows that the deep fault in the Koyna area is aligned in the NNW-SSE direction.Refraction seismic data analysis by the wave front method reveals that the thickness of the Deccan Trap increases towards the west coast. The Deccan Trap is 600–700 m thick in the eastern region between Nira (SP 130) and Loni (SP 200) and attains a thickness of 1500 m at 10 km east of the west coast. The longitudinal wave velocity in the Deccan Traps along the profile varies from 4.8 to 5.0 km/sec and in the crystalline basement from 6.0 to 6.15 km/sec. A tentative isopach contour map of the Deccan Traps and a tentative structural contour map of the Pre-Deccan Trap contact have been prepared for the Koyna reservoir area from the results along the Koyna II and Koyna I profiles. A flexure aligned in a NNW-SSE direction, in the Pre-Deccan Trap contact, which is an expression of the deep fault into the basement, has been clearly brought out. The flexure coincides in general with the orientation of the Deccan volcanic scarp in this area.     

A T-shaped four-electrode configuration for resistivity profiling over thin vertical conducting veins

A new variant of the four-electrode system is proposed for geophysical resistivity investigations, particularly for profiling over conductive bodies. Model tank resistivity profiling experiments with Wenner, Schlumberger and the proposed T-shaped four-electrode arrays were carried out over a thin conducting vein type model to evaluate the efficacy of the new array. The proposed array appears to possess a larger response, a greater depth of investigation and a higher vertical resolution in detecting conducting bodies, as compared to the two-conventional arrays.     

Hydrography and circulation in the northwestern Bay of Bengal during the retreat of southwest monsoon

The distribution of temperature and salinity in the upper 500 m of the northwestern Bay of Bengal, adjoining the east coast of India, during the retreat of southwest monsoon (September) of 1983 is presented. This study reveals coastal upwelling (limited to the upper 40 m) induced by the local winds. Waters of higher surface salinity near the coast characterize the upwelling. The freshwater influx near the head of the Bay diluted the surface salinity to as low as 26.0 × 10⁻³. The surface circulation was weak and led to a net transport of 2.0 × 10⁶m³.s⁻¹ directed towards northeast.     

Sedimeitfology,geochemistry and discriminant analysis in the engineering geological investigation of damsites,Lower Gordon Area,Tasmania

Application of sedimentological, geochemical and discriminant analysis techniques to the engineering geological investigation of damsites assists in understanding the variation of rock types, stratal correlation, porosity, folding and faulting, through studying the history of depositional and diagenetic environments.

Factor analysis (Rao & Naqvi, 1977) resulted in the proposal of a tidal depositional model consisting of subtidal, shoal, bar, intertidal and supratidal carbonate environments, and channels and dune‐and‐flat terrigenous environments. Discriminant analysis has now been employed to extend the paleo‐environmental model laterally. Samples (142) from four new drill holes were examined, and the data compared with the earlier data by a discriminant analysis technique. The results confirm our pre‐existing model of a prograding tidal complex.

Regional correlation of depositional environments of strata shows an anticlinal structure. Faulting in the sequence is indicated by secondary dolomitisation, breccia‐tion and stfatal discontinuities. The secondary dolomites replaced both limestones and sandstones in the sequence. The amount of porosity is related to depositional facies and dolomitisation. It is possible to understand the hydrologic regime with the aid of regional structure, depositional and diagenetic facies, and porosity.

Because this factor and discriminant analysis technique intensively uses information from each length of drill core, the possibility exists of more confident interpretation of new data from less extensive drilling, with consequent saving in cost.