The nature of ancient hydrological systems onMars has been the subject of ongoing controversy, driven largely by a disconnect between observational evidence for flowing water on the Martian surface at multiple scales and the incompatibility of such observations with theoretical models that predict a cold early Martian environment in which liquid water is unstable. Here we present geochemical da...

The most notable trend in the sedimentary iron isotope record is a shift at the end of the Archean from highly variable δ56 Fe values with large negative excursions to less variable δ56 Fe values with more limited negative values. The mechanistic explanation behind this trend has been extensively debated, with two main competing hypotheses: (i) a shift in marine redox conditions and the transit...

the kalat formation is one of units in the kopet dagh sedimentary basin and so far have been studied by other fossils (case study) (palynomorphs, calcareous nanoplankton and foraminifera). according to the important ostracoda in diagnosis paleoecology and paleoenvironment, in this study, investigated ostracoda in shale units of the kalat formation in chahchaheh section have been studied for the...

  Introduction Identification of the climate changes is important for understanding the paleoenvironmental characteristics. Sedimentary evidence of the closed basins can be one of the most important methods for identifying the climatic periods and changes in the sedimentary environments. Gavkhouni Playa, as the lowland of the ZayandehRud River catchment area is located in an inter-mountainous...

in this study, depositional environment and provenance of sandstones of the surijeh formation (lower cretaceous) in the abgarm section in the kopet-dagh basin are investigated. analysis of sedimentary facies in this section shows that there are two clastic (continental and coastal plain) and two carbonate (coastal plain) facies associations are present. the results of modal analysis and geochem...

in order to study the stratigraphic of sedimentary deposits of the cenomanian in kopeh dagh, the taghiabad section was selected. in the eastern kopeh dagh, the upper part of aitamir formation has this time range characteristic. the upper part of this formation includes shale and glauconitic sandstones and contains variety of ammonite fauna. ten genera and species of ammonites are found inside t...

Sedimentary Copper mineralization has been observed in Monj and Jolany locations in Bavanat (Sanandaj – Sirjan metamorphic belt). According to current study, the host rocks for copper mineralization in this area are green sandstones, generally in subarkose and arkose groups. Age of these sandstones is middle Jurassic. Copper mineralization is observed in two forms, sulfides form including chalc...