Provenance of buried esker groundwater: the case of Vars-Winchester esker aquifer,Eastern Ontario,Canada

An innovative mode of groundwater recharge to a buried esker aquifer is considered. The current conceptual model affords a natural safeguard to underlying aquifers from the overlying muds. A hypothesis of groundwater recharge to a buried esker aquifer via preferential pathways across its overlying muds is tested here by heuristic numerical one-dimensional and two-dimensional modeling simulations. The hypothesis has been tested against two other conventionally accepted scenarios involving: (1) distal esker outcrop areas and (2) remote shallow-bedrock recharge areas. The main evidence comes from documented recharge pressure pulses in the overlying mud aquitard and in the underlying esker hydraulic-head time series for the Vars-Winchester esker aquifer in Eastern Ontario, Canada. These perturbations to the potentiometric surface are believed to be the aquifer response to recharge events. The migration rate of these pressure pulses is directly related to the hydraulic diffusivity of the formation. The measured response time and response amplitude between singular radar precipitation events and well hydrographs constituted the heuristic model calibration targets. The main evidence also includes mud-layering deformation (water escape features) which was observed in seismic surveys of the over-esker muds. These disturbed stratigraphic elements provide a realistic mechanism for migrating water to transit through the muds. The effective hydraulic conductivities of these preferential pathways in the muds were estimated to be between 2?×?10^?6 and 7?×?10^?6 m/s. The implications of these findings relate to the alleged natural safeguard of these overlying muds.     

Strain localization due to structural in-homogeneities in the Central European Basin System

The large-scale crustal deformations observed in the Central European Basin System (CEBS) are the result of the interplay between several controlling factors, among which lateral rheological heterogeneities play a key role. We present a finite-element integral thin sheet model of stress and strain distribution within the CEBS. Unlike many previous models, this study is based on thermo-mechanical data to quantify the impact of lateral contrasts on the tectonic deformation. Elasto-plastic material behaviour is used for both the mantle and the crust, and the effects of the sedimentary fill are also investigated. The consistency of model results is ensured through comparisons with observed data. The results resemble the present-day dynamics and kinematics when: (1) a weak granite-like lower crust below the Elbe Fault System is modelled in contrast to a stronger lower crust in the area extending north of the Elbe Line throughout the Baltic region; and (2) a transition domain in the upper mantle is considered between the shallow mantle of the Variscan domain and the deep mantle beneath the East European Craton (EEC), extending from the Elbe Line in the south till the Tornquist Zone. The strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the CEBS.     

Comprehensive studies in the Black Sea and the Sea of Azov in the Summer of 2012

The shelf zones of the Black Sea, Taman Bay, and the Sea of Azov are currently subjected to gross load related to the impact of invasive species, large-scale construction activities near the coast, intensive recreation activity, water pollution in large cities and ports, active navigation, unreasonable coastal arrangement, and dam construction. Another factor substantially affecting the composition of bottom sediments and, thus, the benthos environment is the terrigenous material carried by rivers in the course of catastrophic overflows. An example is the Kubansk flood in 2012, which significantly affected the sea coast near Novorossiysk, Gelendzhik, and Divnomorsk. The intensive onshore dumping results in the delivery of abundant allochthonous material, bottom silting causing changes in the dominants in the benthos associations, a decrease in the photic layer and the death of the phytobenthos, and also debris formation at the bottom. Debris can play the role of artificial reefs contributory for the formation of periphytic biocoenoses.     

Isotopic tracers for water masses in the coastal region of eastern Hokkaido

In this study we used two stable isotopes, δ¹³C and δ¹⁸O, for water mass classification in the coastal region off eastern Hokkaido. δ¹³C* values, which were corrected for the biological effect, and δ ¹⁸O values up to 300 m depth suggested that the isotopic character of the onshore and offshore water in the southern Okhotsk Sea, the Nemuro Strait and the western North Pacific could be explained by the mixing of three source waters: the Oyashio water (OYW), Soya Warm Current water (SWCW) and East Sakhalin Current water (ESCW). In summer, δ ¹³C*-δ ¹⁸O plots indicated mixing between SWCW from the southern Okhotsk Sea and OYW in the Pacific coast of southeastern Hokkaido, while temperature-salinity plots of the onshore water showed minimal difference from the offshore OYW. In winter, on the other hand, the mixed water of ESCW and OYW (or SWCW) appeared in the Pacific coastal region, distributed as cold, low salinity onshore water. Finally, we estimated mixing ratios of OYW, SWCW and ESCW in the coastal region of western North Pacific using their mean values of δ ¹³C* and δ ¹⁸O as endmembers. These results suggest seasonal and yearly changes of water mass combination en route from the southern Okhotsk Sea to the western North Pacific.     

On mass transport in deep water waves

Summary Various formulations of the mass-transport problem are compared for progressive waves in deep water. In order to calculate the mass-transport velocity as a function of depth in the main body of the fluid, it is necessary to include the effect of viscous wave attenuation. It is shown that the usual assumptions of periodicity in distance and attenuation with time or periodicity in time and attenuation with distance, are both physically unsatisfactory. The first does not specify a unique solution, and the second is incompatible with the assumption of zero surface stress. A certain critical constant tangential wind stress will maintain strictly time-periodic deep water waves. The corresponding attenuation with distance is then calculated to order ³. A constant tangential stress greater or less than the critical causes waves, necessarily decaying with distance, to grow or decay with time.     

Use of Carbonatites in the Production of Precipitated Calcium Carbonate: A Case Study from Eppawala,Sri Lanka

The study investigates the possibility of using carbonatite in the production of precipitated calcium carbonate (PCC). We made use of fresh apatite-rich carbonatites found at the phosphate mining sites at Eppawala, Sri Lanka. Analyses of the fresh carbonatite were performed with the aid of optical microscopy, powder X-ray diffraction (XRD), atomic absorption spectrophotometry (AAS), UV/visible spectrophotometry (UVVS), and thermo gravimetric analysis (TGA). Quicklime obtained from calcinations of carbonatites was used in synthesizing PCC via a lime-soda process. The end product was analyzed with XRD, TGA, AAS, and UVVS. Results revealed that the most common CO₃ ^2? phase available in fresh carbonatites is calcite (>65%). The Ca-rich CO₃ ^2? phase can be distinguished easily from other available minerals because its mode of occurrence in carbonatite matrix is different to that of other minerals. The results of TGA show that the decomposition of CO₃ ^2? phase initiates at about 340°C, which leads to lower energy consumption during calcinations. Post-magmatic hydrothermal process may have been the cause of the formation of thermally unstable CO₃ ^2? phases. Hydration of quicklime from the carbonatite yields much higher Ca²⁺ in the solution than from marble under the same experimental conditions. The synthesized PCC particles are in the calcite polymorphic form. The purity of PCC varies from 96 to 98 wt%. The maximum precipitable CaCO₃ from 1 g of quicklime is about 1.1 g. Hence, fresh carbonatites has great economic potential for the production of PCC.     

Shell model representation as a substitute of LoD3 for 3D modeling in CityGML

The OGC standard for 3D city modeling is widely used in an increasing number of applications.It defines five consecutive Levels of Detail(LoD0 to LoD4 with increasing accuracy and structural complexity),in which LoD3 includes all exterior appearances and geometrical details and subsequently requires much storage space.A new LoD is introduced as shell model with the exterior shell of the LoD3 model and the opening objects like windows,doors as well as smaller faade objects are projected onto walls.In this paper,a user survey is presented.The results of this survey show that the shell model can give users almost the same visual impression as the LoD3 model.Furthermroe,algorithms are developed to extract the shell model from LoD3 model.Experiments show that this shell model can reduce up to 90% storage of the original LoD3 model.Therefore,on one hand it can be used as a substitute for a LoD3 model for the visualization on small displays.On the other hand,it can be treated as a sub-level of detail(SLoD3) in CityGML,since it retains almost the same amount of information but requires much less storage space.     

Kinetics of hydrocarbon generation for Well Yingnan 2 gas reservoir,Tarim Basin,China

Well Yingnan 2, an important exploratory well in the east of Tarim Basin, yields high commercial oil and gas flow in Jurassic. Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas. Because this region presents many suits of hydrocarbon source rocks, there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present. By using the kinetics of hydrocarbon generation and carbon isotope, natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas, about 72%, it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir. The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2, so the gas reservoir belongs to late accumulation and continuous filling type.     

Stratigraphic relations and habitat of the Bende fish teeth,southeastern Nigeria

The age and habitat of the Bende fish fossils have remained a matter of controversy with interpretations ranging between the Paleocene Imo Formation and the Eocene Ameki Formation. Outcrop-based sequence stratigraphic analysis presented in this work shows that the Imo and Ameki Formations together include three laterally extensive estuarine central basin/offshore mud rock units that are associated with the 59.7, 58.1, and the 56.8 ma maximum flooding surfaces, respectively. Field evidence and stratigraphic analysis show that the Bende fossil bones are hosted by the mud rock unit containing the 58.1 ma maximum flooding surface, while the Ameke bone fossils are contained within the condensed section associated with the 56.8 ma maximum flooding surface. Apart from highlighting the relevance of sequence stratigraphy in paleobiological interpretations, this study shows that the Bende fish fauna which Arua first assigned to the Eocene Ameki Formation indeed belongs to the Paleocene Imo Formation.     

Three-dimensional thermal structure of the Chinese continental crust and upper mantle

We invert S-wave velocities for the 3D upper-mantle temperatures, in which the position with a temperature crossing the 1300℃ adiabat is corresponding to the top of the seismic low velocity zone. The temperatures down to the depth of 80 km are then calculated by solving steady-state thermal conduction equation with the constraints of the inverted upper-mantle temperatures and the surface temperatures, and then surface heat flows are calculated from the crustal temperatures. The misfit between the calculated and observed surface heat flow is smaller than 20% for most regions. The result shows that, at a depth of 25 km, the crustal temperature of eastern China (500―600℃) is higher than that of western China (<500℃). At a depth of 100 km, temperatures beneath eastern and southeastern China are higher than the adiabatic temperature of 1300℃, while that beneath west China is lower. The Tarim craton and the Sichuan basin show generally low temperature. At a depth of 150 km, temperatures beneath south China, eastern Yangtze craton, North China craton and around the Qiangtang terrane are higher than the adiabatic temperature of 1300℃, but is the lowest beneath the Sichuan basin and the regions near the Indian-Eurasian collision zone. At a depth of 200 km, very low temperature occurs beneath the Qinghai-Tibet Plateau and the south to the Tarim craton.