Delineation of Integrated Anomaly with Generative Adversarial Networks and Deep Neural Networks in the Zhaojikou Pb-Zn Ore District,Southeast China

Geochemical maps are of great value in mineral exploration. Integrated geochemical anomaly maps provide comprehensive information about mapping assemblages of element concentrations to possible types of mineralization/ore, but vary depending on expert’s knowledge and experience. This paper aims to test the capability of deep neural networks to delineate integrated anomaly based on a case study of the Zhaojikou Pb-Zn deposit, Southeast China. Three hundred fifty two samples were collected, and ea...     

Spectrum of the geomagnetic field in central Europe

mam na n uu nmaaum n a mumuu ¶rt; n. ammu ama 27-¶rt;a auau uuauuu n amuaa 7 ¶rt;nu amu nu¶rt; 1960–68 . ¶rt;a m ¶rt; mum nma maa m nmaum n nu a amumu.     

Response of Nereis diversicolor (Polychaeta, Nereidae) populations to reduced wastewater discharge in the polluted estuary of Oued Souss, Bay of Agadir, Morocco

Field investigations on the population dynamics of Nereis diversicolor were carried out from January 2002 to December 2003 in the estuary of Oued Souss (southwestern Morocco) to determine the changes caused by setting up of a domestic and industrial wastewater purification plant (M'zar) before and after by the end of wastewater discharges in November 2002 on the structure of the ecosystem. Samples of N. diversicolor were collected monthly in the intertidal zone at low tide before (during 2002) and after (during 2003) the end of wastewater discharges.Separation of cohorts using the Algorithm EM method (McLachlan, G.J., Krishnan, T., 1997. The EM algorithm and extensions. Wiley Series in Probability and Statistics. Wiley, New York, 274 pp.) allowed determination of the growth rate (mm day⁻¹) by cohort and the annual production. The data showed significant differences between populations of Nereis diversicolor before and after the end of wastewater discharges. During the wastewater discharge period (2002), the population had a mean annual density of 1992 ind m⁻², a mean annual biomass of 75.52 g DW m⁻² and an annual secondary production of 141.3 g DW m⁻² with a P/B ratio of 1.87. After the end of discharges (2003), density, biomass and secondary production decreased significantly. The annual averages for these parameters were 740 ind m⁻², 14.16 g DW m⁻² and 23.83 g DW m⁻², respectively, with a P/B ratio of 1.68.The important decrease observed in density, biomass and secondary production of Nereis diversicolor may be attributed (a) to the environmental changes observed after the end of wastewater discharges in the estuary of Oued Souss, namely the increase of salinity and the decrease of organic matter content, and (b) to the migration of this species towards other areas.     

Composition and properties of the iron hydroxides-cemented lenses in Estonian sandstone of Middle Devonian age

The formation of hematite and goethite concretions in different sedimentary rocks including sandstones is an important diagenetic process in the geologic history of the Earth. Its interpretation can also contribute to understanding the diagenetic history of Martian iron hydroxide concretions. A case study of iron-rich concretions from Estonian Middle Devonian sandstones exposed in ancient river valleys in southeastern Estonia was carried out based on the results of mineralogical, petrographical, geochemical, petrophysical and magnetic analyses. It was found that the high Fe₂O₃(total) content (25.0–39.5%), high magnetic susceptibility, bulk and grain density, very low porosity, corrosion and fracturing of the quartz grains of the platy iron concretions are in contrast with properties of the Devonian host sandstones. However the ferrous iron content (measured as FeO) of iron-rich concretions was as low as in the other Devonian rocks, suggesting an oxidizing environment and arid climate during the cementation by iron-hydroxides. The fracturing of quartz grains cemented by iron hydroxides could take place at near-surface conditions including vadose and phreatic zones in arid climate with high evaporation rates. Such climatic conditions have been reported for the Baltic region during Devonian, Upper Permian and Triassic times. We have found that goethite is prevalent in the cement, replacing clay and carbonate minerals. We assume that this iron-rich cement is originated from the mobilization of iron in host sandstones by groundwater, associated with tectonic activity at the end of the Middle Devonian, evidenced by fracturing in Devonian outcrops and caves. Although this mobilization could occur under reducing conditions, precipitation of goethite and hematite for the cementation could take place in oxidizing environment along bedding planes close to the surface during short sedimentation breaks. Another possible time for the formation of iron concretions could be Permian, under the condition of both arid climate and tectonic activity.     

Association of the scallop Patinopecten yessoensis and epibiotic barnacle Balanus rostratus: inter‐specific interactions and trophic relationships determined by fatty acid analysis

Marine mollusks provide shelter to epibiotic organisms which settle on the outer surface of their hard shells. Epibionts can exert beneficial or detrimental effects on the host mollusk. In this study, the ecology of the association of the commercially valuable marine mobile scallop Patinopecten (=Mizuhopecten) yessoensis with its epibiotic barnacle Balanus rostratus was investigated. Fatty acid analysis was performed to determine the trophic relationships between these species. The distribution of fatty acid markers in this scallop species suggests an important contribution of diatoms, flagellates and animal material in its diet. The fatty acid analysis indicated a predominance of diatoms in the diet of the adult barnacles and some detrital input into the diets of young individuals. It was found that adult barnacles may compete with the scallops for food sources such as diatoms and zooplankton. It was revealed that with a negligible biomass of epibionts, the interactions between the barnacle and scallop may be regarded as commensalisms. An increase in the weight of epibiotic barnacles resulted in decreases in the weights and shell heights of the scallops, testifying to the adverse influence of a high biomass of epibionts on their host.