Exploring Radioisotopic Geochronology and Astrochronology

Noninvasive Radioisotopic Technique

At 8 and 32 hours after saphenous vein bypass graft surgery in six dogs, in vivo images of the graft were obtained with a gamma camera after intravenous injection, 2 hours postoperatively, of autologous platelets labeled with indium-111. Platelet deposition in the grafts could be imaged in vivo from the scintiphotos. In vitro images of the excised heart showed saphenous vein graft uptake confir...

Stratigraphy and Relative Geochronology

Stratigraphy is the science that studies the strata, or beds, of (mainly) sedimentary rocks in order to extract from them the history of the earth’s surface. By grouping the bed successions in stratigraphic units and by studying their geometrical relationships with some simple rules, it creates the fundamental temporal relative framework necessary to understand the origin of the rock units them...

Models of Garnet Differential Geochronology

Rayleigh distillation models are developed to describe theoretical growth zoning of Lu, Hf, Rb, Sr, Sm, and Nd in typical garnet crystals from metapelites and metabasites. Effects of diffusion-limited transport within the matrix and intracrystalline diffusion are also considered qualitatively. Theoretical zoning profiles show strong depletions of Lu in garnet rims compared to cores, but virtual...

Astrochronology for the Early Cretaceous Jehol Biota in northeastern China

The brunhes epoch: isotopic paleotemperatures and geochronology.

Oxygent isotopic analysis of a long piston core from the western equatorial Pacific has produced a record for the entire Brunhes epoch. This record can be correlated point by point with the isotopic records of previously analyzed Atlantic and Caribbean cores, leading to the construction of a generalized temperature curve for the entire Brunhes epoch.