Integration of Sequence Stratigraphic Analysis and 3D Geostatistical Modeling of Pliocene–Pleistocene Delta,F3 Block,Netherlands

This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this research.The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section.Integration of seismic sequence stratigraphic interpretation,using well logs,and subsequent 3D geostatistical modeling,using seismic data,aided to evaluate the shallow hydrocarbon traps.The resulting models were obtained using System Tract and Facies models,which were generated by using sequential stimulation method and their variograms made by spherical method,moreover,these models are validated via histograms.The CDF curve generated from upscaling of well logs using geometric method,shows a good relation with less percentage of errors(1 to 2 for Facies and 3 to 4 for System Tract models)between upscaled and raw data that complements the resulted models.These approaches help us to delineate the best possible reservoir,lateral extent of system tracts(LST and/or HST)in the respective surface,and distribution of sand and shale in the delta.The clinoform break points alteration observed on seismic sections,also validates the sequence stratigraphic interpretation.The GR log-based Facies model and sequence stratigraphy-based System Tract model of SU-04-2 showed the reservoir characteristics,presence of sand bodies and majorly LST,respectively,mainly adjacent to the main fault of the studied area.Moreover,on the seismic section,SU-04-2 exhibits the presence of gas pockets at the same location that also complements the generated Facies and System Tract models.The generated models can be utilized for any similar kind of study and for the further research in the F3 block reservoir characterization.

Addressing ore formation and exploration

Common base and noble metals represent an important economic factor in the actual industrial development.For instance the world resources for copper are actually estimated for about the next 30 years only.The situation requires rethinking the way major ore deposits form,leading to new guides for exploration.The present paper briefly examines the processes leading to ore formation,in relation with granitic or granodioritic intrusions.It identifies the importance of metal enrichment during the magmatic stage.Within the magma chamber that forms porphyry intrusions,metals may incorporate to first formed crystals,becoming inert;concentrate into the residual melt of a mush;or segregate by diffusion into the exsolved magmatic volatile phase(MVP)into which they are transported and precipitated.A competition results between elements partitioning and diffusivity.Hence,a specific Peclet number for each metal(Cu,Au,Ag,Mo,W,Sn,and REE)controls the ratio between the diffusive and the advective flux.Metals diffusivity in the melt shows differential behavior relative to a threshold of about10 13 m2/s.Metals with slower diffusivity values(e.g.As)will not concentrate.Conversely,fast diffusive metals(Au,Ag,Cu)may rapidly incorporate the MVP,provided an adequate component(halogens or S)is attractive for metals.The chemistry of the MVP escaping the magma induces different alteration patterns.Their relative content in F,Cl or S,attested by the composition of biotites and apatites,links with the preferential content of metals in o re deposits,representing a valuable tool for exploration.Finally the model is replaced in a set of coupled mechanical-chemical instabilities,within a three phase material.

Groundwater Chemical Evolution in the Essaouira Aquifer Basin—NW Morocco

The sustainability of groundwater resources for drinking water supplies, agriculture, and industry a prime concern in countries dominated by arid and semi-arid climates such as Morocco. The growing demand for groundwater coupled with impacts from land use and climate change make sustainability an even more important water management goal. In order to make sound decisions about water use and protection of water quality, managers and policy makers must have a sound understanding of such factors as the location and amount of groundwater recharge and groundwater ages. Due to the population growth and climate change (causing long periods of drought) in the world, many countries have intensively increased their use of water sources for supplying potable water to population and for their agricultural (irrigation) and industrial developments. Due to the lack of surface waters, people exploit mainly underground water reservoirs. So, it is necessary to study and characterize these water reservoirs to avoid any excess of exploitation. The water resources of the Essaouira basin are characteristic of a semi-arid climate, and are severely impacted by the climate (quantity and quality). Considering the importance of the Essaouira aquifer in the groundwater supply of the region, a study was conducted in order to comprehend this aquifer groundwater evolution. It is an aquifer located on the Atlantic coastline, southern (Morocco), corresponding to a sedimentary basin with an area of near200 km2. Covering the Palaeozoic bedrock, the sedimentary series range from the Triassic to the Quaternary. The geological structures delineate a syncline bordered by the Tidzi diapir of Triassic age which outcrops to the East and South. In the Essaouira basin a multi-aquifer was identified constituted by detrital deposits of the Plioquaternary and dolomitic limestones of the Turonian. The Plioquaternary is unconfined below the Senonian marls. However, in some places it can be in direct contact with the other Cretaceous and Triassic units. The Plioquaternary is generally up to60 mthick. The Turonian is confined by the Senonian marls and in direct contact with the Plioquaternary on the edges of the syncline structure. The main flow direction is from SE to NW towards theAtlantic Ocean, being the recharge area located near the Tidzi diapir. In the Essouaira basin, in spite of the occurrence of calcareous and dolomitic levels, all waters are of Na-Cl-type. The chemical signature of these waters should be the result of the preferential recharge area that is located in the Tidzi diapir. Using a simple mass balance model through the PHREEQC program this scenario was tested. The reaction path was assumed to be such that waters observed at shallow depths evolved to more mineralized waters. It was possible to notice that these waters have an important contribution of water-rock interaction in groundwater mineralization, corroborating the influence of the preferential recharge area located in the Tidzi diaper in the waters signature.

Environmental Impact of Mining Exploitation: A Case Study of Some Mines of Barite in the Eastern Anti-Atlas of Morocco

Extraction of mineral resources is the backbone of the national economy in many developed and developing countries of the world. However, the exploitation can have many negative impacts on the immediate environment of the exploitation sites. In this study performed on some mining areas of the Moroccan Anti-Atlas, four principal negative effects were detected: effect on the physiognomy, on safety, on health, and on recovery rate. The principal source of this situation is the exploitation of the ore deposits from top to bottom without using any geological preparation and the use of non-adapted exploitation technics. To minimize these impacts, we propose to establish a geological study and advanced mining exploration before starting exploitation, and follow an exploitation technic well adapted to the morphology of the ore deposit like cut-and-fill mining and sublevel stoping methods.

Validation Approach of the Tectonic Lineament Extraction Enhancement Using Sentinel 2A Images and Modified 3 ×3 Bidirectional Prewitt Filters. Case Study: Grombalia, Tunisia

In this study, filters are used to extract directional tectonic lineaments and, thus, to reveal the presence of faults or fractures in the satellite images. The extraction process consists first in eliminating other different types of lineaments (e.g. the lithological limit, ridgelines, hydrographic network, roads, etc.). Besides, a comparative and quantitative approach is applied to show that when the directional Prewitt filter has a zero setting of the opposite of the assumed direction, as is the case of the N-S direction, the East-West direction is also set to zero. This research work, based on a bidirectional filter (N-S;E-W), shows satisfactory results especially concerning the quantitative fluctuation of lineament directions by interval. This fluctuation is in perfect agreement with the lineaments provided by the digitizing of the different tectonic accidents directions extracted in a GIS environment from the geological map of Grombalia. In this research work, a quantitative approach was used to evaluate the result of the lineament extraction methodology based on one direction analysis and by an interval of directions. Indeed, the N45 lineament direction, well documented in the geological study of the region, was more clearly distinguished by applying the Prewitt filter than by using the Sobel filter. The result was validated by comparison with the results obtained by the digitization of the tectonic accidents mapped on the geological map.

How rock samples can be representative of in situ condition:A case study of Callovo-Oxfordian claystones

Within the framework of feasibility studies for a reversible, deep geological repository of high-and intermediate-level long-lived radioactive waste(HLW, IL-LLW), the French National Radioactive Waste Management Agency(Andra) is investigating the Callovo-Oxfordian(COx) formation near Bure(northeast part of France) as a potential host rock for the repository. The hydro-mechanical(HM) behaviour is an important issue to design and optimise different components of the disposal such as shaft, ramp, drift,and waste package disposal facilities. Over the past 20 years, a large number of laboratory experiments have been carried out to characterise and understand the HM behaviours of COx claystones. At the beginning, samples came from deep boreholes drilled at the ground surface with oil base mud. From2000 onwards, with the launch of the construction of the Meuse/Haute-Marne Underground Research Laboratory(MHM URL), most samples have been extracted from a large number of air drilled boreholes in the URL. In parallel, various constitutive models have been developed for modelling. The thermohydro-mechanical(THM) behaviours of the COx claystones were investigated under different repository conditions. Core samples are subjected to a complex HM loading path before testing, due to drilling, conditioning and preparation. Various kinds of effects on the characteristics of the claystones are highlighted and discussed, and the procedures for core extraction and packaging as well as a systematic sample preparation protocol are proposed in order to minimise the uncertainties on test results. The representativeness of the test results is also addressed with regard to the in situ rock mass.

Radiolarian and Planktic Foraminifera Biostratigraphy of the Early Albian Organic Rich Beds of Fahdene Formation,Northern Tunisia

The lower part of Fahdene Formation outcropping in northeastern Tunisia is repre- sented by pelagic sequences and characterized by an important siliciclastic fraction that includes ra- diolarian and organic-rich beds of Allam Member. Litho-biostratigraphic analysis based on planktic foraminifera and radiolaria shows that deposition of organic-rich beds of Allam Member is confined to the Microhedbergella rischi Zone through the lower part of Ticinella primula Zone. Age diagnostic radiolaria recovered from these beds has been identified to constrain a direct age of black shale depo- sition. The assemblages can be correlated with the radiolarian biochronozone U.A.10-11 indicating an Early Albian to early Middle Albian in age. Radiolarian assemblages composed of species characteris- tic of U.A.10 biochronozone （A. montisserei, D. gracilis） are associated with radiolarian taxa belonging to Costata Zone （U.A.9 Pseudoeucyrtis hanni and Thanarla pseudodecora）, which can be correlated with Dercourt Member in the Ionian Zone and Paquier level of the Vocontian Basin （southeast of France）. Biostratigraphic and abundance curves analysis has demonstrated significant diversification of cryptocephalic Nassellaria and Archaeodictyomitrae, probably adapted to eutrophic conditions that characterized the Aptian-Albian transition. Ecological conditions may have governed the stratigraphic range of many cosmopolitan taxa （i.e., Pseudodictyomitrae lodogaensis） compared with stratigraphic distributions schemes reported from other domains. The timing of black shales deposition was dia- chronic due to local geodynamic conditions and upwelling currents distribution. The Allam black shales are correlative with the oceanic anoxic event OAElb which is characterized by the widespread of supraregionnally organic-rich beds in the Mediterranean Tethys basins across the Aptian-Albian transition.

Thermal stability and spectroscopic properties of Ho^(3+) doped tellurite-borate glasses

Ho3＋ ions doped tellurite-borate glass samples with varying compositions were prepared. The compositional dependence on phenomenological Judd-Ofelt parameters was compared in different kinds of rare earth ions doped tellurite-borate glasses. Two methods were used to obtain radiative transition probability of 517 level with the aim of assuring the fitting quality. The integral absorption cross-sections and line shapes corresponding to 518--.5G6 and 518---5I7 transition of Ho3＋ ions were investigated in tellurite-borate glasses. The obtained data indicated that the integral absorption cross-sections corresponding to 518-5G6 transition of Ho3＋ ions mainly depended on phenomenological Judd-Ofelt parameter, g22, because 518---5G6 transition belonged to hypersensitive transitions, which led to a larger gP2 value. The change of line shapes of absorption spectra corresponding to 518-5G6 and 518-517 transitions of Ho3＋ ions came from the lower energy regions, which could be attributed to the changed distribution of Stark levels and thermal population.

Effect of Water Quality on Heavy Metal Redistribution and Mobility in Polluted Agricultural Soils in a Semi-Arid Region

Mornag Plain is a coastal area of the Mediterranean basin, which has undergone an agricultural industrial boom. The aim of this study was to investigate the different water qualities used for irrigation on heavy metal mobility in these polluted agricultural soils. The geo-accumulation indices for heavy metals (Ni, Cr, Pb, Cd, Cu, and Zn) revealed that industrial activities and used treated wastewater (TWW) contributed to soil pollution, and water irrigation always decreased this contamination. After long-term use of different water types, high perturbation of heavy metal redistribution has occurred. Groundwater use altered all heavy metal redistributions in the irrigated soil among various soil-solid and soil-solution fractions, as compared to the unirrigated soil. Slight acid water use transferred some metals from different solid phase components into water-soluble and exchangeable fractions. However, TWW use transformed some Ni, Cr, Cd, Cu, and Zn from water-soluble and exchangeable fractions to less labile fractions, particularly into organically bound fractions. Reuse of conventional water within the same soil decreased the whole soil redistribution index values, indicating tendency to return to the pattern of distribution of groundwater-irrigated soil.

Classification of Sandstone-Related Uranium Deposits

Sandstone type deposits are the most common type of uranium deposits in the world.A large variety of sub-types have been defined,based either on the morphology of the deposits(e.g.,tabular,roll front,etc),or on the sedimentological setting(e.g.,paleovalley,paleochannel,unconformity),or on tectonic or lithologic controls(e.g.,tectonolithologic,mafic dykes/sills),or still on a variety of others characteristics(phreatic oxidation type,interlayer permeable type,multi-element stratabound infiltrational,solution front limb deposit,humate type,etc.),reflecting the diversity of the characteristics of these deposits,but making it difficult to have a clear overview of these deposits.Moreover,uranium deposits occurring in the same sedimentological setting(e.g.,paleochannel),presenting similar morphologies(e.g.,tabular),may result from different genetic mechanisms and thus can be misleading for exploration strategies.The aim of the present paper is to propose a new view on sandstone-related uranium deposits combining both genetic and descriptive criteria.The dual view is indeed of primordial importance because all the critical characteristics of each deposit type,not limited to the morphology/geometry of the ore bodies and their relationships with depositional environments of the sandstone,have to be taken into account to propose a comprehensive classification of uranium deposits.In this respect,several key ore-forming processes,like the physical-chemical characteristics of the mineralizing fluid,have to be used to integrate genetic aspects in the classification.Although a succession of concentration steps,potentially temporally-disconnected,are involved in the genesis of some uranium mineralization,the classification here proposed will focus on the main mechanisms responsible for the formation and/or the location of ore deposits.The objective of this paper is also to propose a robust and widely usable terminology to define and categorize sandstone uranium deposits,considering the diversity of their origin and morphologies,and will be primarily based on the temperature of the mineralizing fluid considered as having played the critical role in the transportation of the uranium,starting from synsedimentary uranium deposits to those related to higher temperature fluids.