The Solstad copper deposit, located in SE Sweden, is hosted by a quartz-rich rock sliver surrounded granite belonging to the 1.8 Ga Transscandinavian Igneous Belt. Ore petrographic studies have revealed number of previously unrecognized opaque phases, including several Co selenides and tellurides. Based on an situ U-Pb investigation zircons from mineralized sample, it suggested that detrital or...

We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarseto medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated wi...

The emergence of oxygen-producing (oxygenic) photosynthesis fundamentally transformed our planet; however, the processes that led to the evolution of biological water splitting have remained largely unknown. To illuminate this history, we examined the behavior of the ancient Mn cycle using newly obtained scientific drill cores through an early Paleoproterozoic succession (2.415 Ga) preserved in...

Whether or not coarse detrital sedimentary rocks occur within the \3.7 Ga Isua Greenstone Belt (IGB), southern west Greenland, has been debated for some time. Repeated, regional metamorphic, deformational, and metasomatic events have obscured most protolith lithologies leading to misunderstandings about the stratigraphy and environments of deposition. Rocks here interpreted as meta-conglomerate...

We present results from geomorphic mapping and visible to near-infrared spectral analyses of the Jezero crater paleolake basin and its associated watershed. The goal of this study is to understand the provenance of the sedimentary deposits within this open-basin lake using a source-to-sink approach. Two fan deposits located within the basin have distinct visible to near-infrared mineralogic sig...

Monoclinic pyrrhotite (Fe7S8) is widely claimed to carry magnetizations acquired during early diagenesis in anoxic sedimentary environments. In contrast, geochemical literature indicates that pyrrhotite formation is extremely slow below 180 8C, which makes it a highly unlikely carrier of early diagenetic remanences in sediments. This view is confirmed by the occurrence of late diagenetic Fe7S8 ...

A new marine ecosystem model designed for the global domain is presented, and model output is compared with field data from nine different locations. Field data were collected as part of the international Joint Global Ocean Flux Study (JGOFS) program, and from historical time series stations. The field data include a wide variety of marine ecosystem types, including nitrogenand iron-limited sys...

We have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the ...

Informal lending and savings institutions exist around the world, and often include regular door-to-door deposit collection of cash. Some banks have adopted similar services in order to expand access to banking services in areas that lack physical branches. Using a randomized control trial, we investigate determinants of participation in a deposit collection service and evaluate the impact of o...

19 Detrital-zircon analysis of sandstones interbedded with ca 464 Ma ignimbrites in 20 the lower Mweelrea Formation of the South Mayo Trough, western Ireland, 21 suggests Ordovician source-rock provenance that corresponds to two distinct 22 volcanic-arc phases on the Laurentian margin. East-derived sandstones contain a 23 suite of zircons with a mean age of ca 487 Ma that suggests derivation fr...