Geochemical study of cherts indicates the following:the SiO 2 content in the cherts is>80%,the average MnO /TiO 2 ratio is0.58,the average Al/(Al+Fe+Mn )ratio is0.48and the average Ce /Ce ratio is0.91.A comparison with the geochemical charac teristics of cherts in the known tectonic setting indicates that they are cherts of oceanic basin-margin type near continental margins.
In contrast,the basalts yielded reasonableγ_(Os)(130Ma) values from 21.4 to 267.8,with initial(~(187)Os/~(188)Os)ratios of 0.1531～0.4639 .Combined Re-Os,Sm-Nd isotopic and trace element geochemical studies indicate that the early Cretaceous basaltic magmas might be derived from depleted rather than enriched mantle source,and may have been contaminated by crustal rocks and melts.
In north of whole three rivers tectonic belt include Jiangda tectonic belt, regional geochemical research indicate that its geochemical anomaly present the character of belt in NW direction and trip in NE direction, too.
A comprehensive lithological-geochemical study of Neopleistocene-Holocene sediments from Russian Arctic showed that these sediments formed in rather similar sedimentation conditions, which were common for polar lithogenesis.
Petrographic and geochemical study of basalts in the Kerguelen Plateau basement revealed changes in the composition and character of volcanism during the development of this tectonovolcanic structure.
Provenance and source of metaterrigenous rocks of the Ladoga Group: Results of geochemical and Sm-Nd isotope-geochemical study
A comparative geochemical study of rare-metal granitoids with various fluorine-bearing minerals (fluorite, topaz, and cryolite) was carried out.
In the mid-1980s, it was concluded based on geochemical study that Th, Sc, La concentrations and ratios Th/Sc, La/Sc and Eu/Eu* did not wary significantly in the post-Archean time.
The mechanisms of association of hydrophobic organic contaminants with natural organic matter (for example humic acid, HA) in soil and sediment are a major objective of environmental and geochemical research.
Geochemical research on C-O and Sr-Nd isotopes of mantle-derived rocks from Shandong Province, China
Consequently, it is concluded that the Late Neoproterozoic bitumens in the Yangtze region, South China, are indigenous to their host rocks, which provides the basis for our organic geochemical research on "Snowball Earth" and "Cambrian Explosion."
This paper presents the results of environmental geochemical research on black shales, soils, waters and edible plants in the Ankang area, Shaanxi Province, P.
Our organic geochemical research has shown that Everglades DOM is more refractory than originally hypothesized.