Hart et al. (1995) postulated that large meteorite impacts may generate characteristic magnetic signatures due to thermal resetting of remanent magnetism, as a consequence of the impact process. Their postulation is based on the results of a study of the ca. 2 Ga Vredefort structure which shows that the remanent magnetism of rocks from the core of the structure was reset penecontemporaneously w...

The Meatiq basement, which is exposed beneath late Proterozoic nappes of supracrustal rocks in the Central Eastern Desert of Egypt, was affected by three metamorphic events. The ophiolite cover nappes show only the last metamorphic overprint. The M1 metamorphic event (T≥750 °C) is restricted to migmatized amphibolite xenoliths within the Um Ba∞anib orthogneiss in the structurally lowest parts o...

Aquifer systems are considered in which measurements of logpermeability (Y) at a 1E-2 m support scale are unimodally distributed as taken within the 1E0 to 1E1 m scale of individual sand and gravel (sg) lithofacies, are weakly multimodal at the 1E1 to 1E2 m scale of assemblages of these facies, and are strongly multimodal at the 1E3 m scale of complexes of sg facies assemblages juxtaposed with ...

Graphitization degrees and temperatures of the regional metamorphism in Central Eastern Rhododpes have been determined by values structural parameter d002 (Å) graphite graphite-bear¬ing marbles shists, from Vacha Madan-Erma Reka areas (Madan lithotectonic unit), Ardino–Nedelino area (Startsevo Chernichevo–Boturche (Byala unit). Equations different authors, formulated between 1951 2021, were use...

In central Victoria, inherited zircon in Devonian igneous rocks and detrital metasedimentary country an amphibolite-facies xenolith show that Mesoproterozoic parts of the underlying Selwyn Block cannot be source for all silicic magmas. Zircon inheritance S-type samples reveals significant thermal events at 525–425 Ma 1200–1100 Ma. Both S- I-type have prominent age peaks 420–410 Ma, which record...

Metamorphism and partial melting of the lower crust is commonly assumed to cause depletion in heat producing elements (HPEs; K, U, Th). In deep crust, volumetrically subordinate metasedimentary layers, which are source crustal granites (sensu lato), host majority Th ± primarily within REE + U Y phosphate mineral monazite. We examine spatial temporal distribution monazite grains rocks from secti...

Abstract Garnet is a fundamental expression of metamorphism and one the most important minerals used to constrain thermal conditions crust. We innovative in situ laser-ablation ICP-MS/MS Lu-Hf geochronology demonstrate that garnet metapelitic rocks enclosing Cambrian eclogite southern Australia formed during Laurentian Mesoproterozoic metamorphism. porphyroblasts amphibolite-facies yielded ages...

Field and Scott Smith [Field, M., Scott Smith, B.H., 1999. Contrasting geology and near-surface emplacement of kimberlite pipes in southern Africa and Canada. Proc. 7th Int. Kimb. Conf. (Eds. Gurney et al.) 1, 214–237.] propose that kimberlite pipes can be grouped into three types or classes. Classical or Class 1 pipes are the only class with characteristic low temperature, diatreme-facies kimb...