christian dating service in - Re os dating pyrite
The absence of the veins in the Rhiconich Terrane is consistent with the suggestion that it was not finally amalgamated to the Assynt Terrane until the Laxfordian.NOTICE: this is the author’s version of a work that was accepted for publication in Precambrian Research,.Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document.
A definitive version was subsequently published in Precambrian Research, 246, June 2014, 10.1016/j.precamres.20.
(2014), Re-Os Dating of Pyrite From the Taocun Fe Deposit, Ningwu Basin, Lower Yangtze River Valley, Eastern China.
Six pyrite samples from the giant Bayan Obo REE-Nb-Fe deposit are dated by Re-Os technique.
Pyrite studied is associated with barite and separated from a vein cutting REE mineralization.
(2014) 'Structural characteristics and Re–Os dating of quartz-pyrite veins in the Lewisian Gneiss Complex, NW Scotland : evidence of an Early Paleoproterozoic hydrothermal regime during terrane amalgamation.', In the Archaean basement rocks of the Assynt and Gruinard terranes of the mainland Lewisian Complex in NW Scotland, a regional suite of quartz-pyrite veins cross-cut regional Palaeoproterozoic (Badcallian, ca. The almost orthogonal orientation of the quartz veins (NE-SW) to the Scourie dykes (NW-SE) are incompatible and must result from distinct paleostress regimes suggesting they are related to different tectonic events.
The quartz veins are overprinted by amphibolite-greenschist facies Laxfordian deformation fabrics (ca. The hydrothermal mineral veins comprise a multimodal system of tensile/hybrid hydraulic fractures which are inferred to have formed during a regional phase of NW-SE extension.
This hypothesis is supported by Rhenium–Osmium dating of pyrite that yields an age of 2249 ± 77 Ma, placing the vein-hosted mineralisation event after the oldest published dates for the Scourie Dykes (2420 Ma), but before the youngest ages (1990 Ma).
Sulphur isotope analysis suggests that the sulphur associated with the pyrite is isotopically indistinguishable from primitive mantle. 2250 Ma quartz-pyrite veins in both the Assynt and Gruinard terranes confirms that these crustal units were amalgamated during or prior to Inverian deformation.
Pyrites analyzed contain 16–30 ng Re and 0.10–0.16 ng Os, and yield a Caledonian isochron age of 439 ±86 Ma.
High Re/Os ratio, low Os concentration and highly radiogenic Os isotopic ratios of these samples suggest that they are of crustal origin.
The northern margin of the North China Block was a passive continental margin, but not a subduction zone with enormous volcanic activities in the Early Paleozoic Era.