Geologic Age Dating Explained
Please note that Sedimentary rock absolute dating Explorer version 8. Please refer to this blog post for more information. Recent advances in the field of geochronology have led to a greater understanding of the scale and duration of geological processes. It is currently possible to date igneous and metamorphic rocks by a variety of radiometric methods to within a million daring, but establishing the depositional age of sedimentary rocks has remained exceedingly difficult.
The problem is most pronounced for Precambrian rocks, where the low diversity and abundance of organisms absolut prevented the establishment of any meaningful biostratigraphic framework for correlating strata. Also, most Precambrian successions have been metamorphosed, rendering original minerals and textures difficult to interpret, and resetting diagenetic minerals. Xenotime YPO 4 is an isotopically robust chronometer, which is increasingly being recognized as a trace constituent in siliciclastic sedimentary rocks.
It may start to grow during early diagenesis, typically forming syntaxial outgrowths on detrital zircon grains. Diagenetic xenotime occurs in a wide variety of rock types, including conglomerate, sandstone, laramie hook up, shale, phosphorite and volcaniclastic rocks, varying from sedimentary rock absolute dating Archaean to Mesozoic in age. The formation of diagenetic xenotime is principally related to redox cycling of Fe-oxyhydroxides and microbial decomposition of organic matter, leading to elevated concentrations of dissolved phosphate and rare earth elements REE in sediment pore-waters.
In addition, it has an exceptional ability to remain closed to element mobility during sedimentary rock absolute dating thermal events, and commonly yields concordant and precise dates. In metamorphosed sedimentary rocks, diagenetic xenotime retains its age information up to lower amphibolite facies in sandstone, and up to mid-upper greenschist facies in pelitic rocks.
Dsting Reviews Sedimentary rock absolute dating 68, Issues 3—4JanuaryPages Radiometric dating of sedimentary rocks: Author links open the author workspace. Birger Rasmussen Opens the author workspace Opens the author workspace School of Earth and Geographical Sciences, University of Western Australia, Crawley, WAAustralia. Abstract Recent advances in the field of geochronology have led to a greater understanding of the scale and duration of geological processes.