In the frame of palaeobotanical studies aimed at identifying reliable molecular markers for determination botanical origins Cretaceous ambers, four diterpenoids from amber Archingeay (Charente-Maritime, South western France) were identified, after chromatographic isolation and detailed nuclear magnetic resonance studies, as 13-hydroxy- 8,13-epoxy-nor-labdanoids. These compounds are structurally...

the badamu formation (upper toarcian-middle bajocian) mainly consists of limestone and shale and has is cropped out in east of iran. the badamu formation conformably overlays shemshak formation and is underlaid sharply by hojedk formation in kerman area and is underlaid gradually by baghamshah formation in tabas and southern khorasan areas. the aim of this work is petrographical study of rocks ...

The mineral barite (BaSO4) can precipitate in a variety of oceanic settings: in the water column, on the sea floor and within marine sediments. The geological setting where barite forms ultimately determines the geochemistry of the precipitated mineral and its usefulness for various applications. Specifically, the isotopic and elemental composition of major and trace elements in barite carry in...

Martian salts: Salts have been identified on Mars by spectrometers on orbiters and rovers. Among them, Mg-, Ca-, and Fesulfates were identified or implied in Meridiani outcrop [1] and in Gusev salty soils and rocks [2,3]; kieserite (MgSO4.H2O) and “polyhydrated sulfates” were found in Valley Marineris, Meridiani Planum, and gypsum (CaSO4.2H2O) near North Pole [4,5,6,7]. Recently, chloride-beari...

We report the concentrations of 22 elements in short coastal sediment cores of Admiralty Bay (King George Island, Antarctica) determined by Neutron Activation Analysis. We focus the discussion on rare earth elements (REE) because their fractionation patterns in sediments relative to local sources may offer insights about weathering, transportation, deposition, and diagenetic processes. We found...

The origin of deep-sea sediments in the western North Pacific Ocean, which are significantly enriched rare-earth elements and yttrium (REY), its paleoceanographic implications have been poorly constrained. Here, we investigated stratigraphic variations chemical compositions textures ferromanganese (Fe–Mn) micronodules separated from sediments. characteristics an extremely REY-rich mud layer var...

[1] Multiproxy data from ODP Hole 1017E (Point Conception, California) provide an excellent opportunity to examine the behavior of barium, within a well‐characterized sedimentary system. Bariumexcess is generally considered to be a productivity proxy; however, in nearshore environments, Baexcess records can be compromised by both sediment provenance and barite remobilization. For the last 60 ky...

Prehistoric cave sediments are often subjected to severe mechanical and chemical alteration, making it difficult to interpret aspects of their archaeology. Theopetra cave offers unique opportunities to resolve aspects of this problem, particularly in relation to chemical changes, because it has a relatively well defined stratigraphy and its older deposits have been subjected to unusually severe...