Introduction: Zircon is a highly refractory and weathering-resistant mineral that has proven useful as an indicator of shock metamorphism in the study of impact structures and formations (e.g., [1-6]). Zircon has advantages compared to quartz or other shockmetamorphosed rock-forming minerals that have been widely used as impact indicators, but are far less refractory than zircon. The purpose of...

Robat-e Zengejeh rocks affected by a variety of events began from Precambrian. This research studied preserved effects of the events. Regional metamorphism is the oldest event in this rocks include schist, amphibolite and orthogneiss, that reached up to amphibolite facies. After this regional metamorphism, it seems that mesocratic (624±5Ma) and hololeucocratic granitoides intruded respectively....

Introduction: The age significance of isotope chronometers in basaltic shergottites is not agreed yet [1-3]. Bouvier et al. [3] argued that crystallization ages of shergottites were old (~4.1 Ga), and suggested that young ages of shergottites (i.e., ~180 Ma) represent reset by shock metamorphism. Baddeleyite (ZrO 2) is an important mineral for U-Pb dating of basaltic shergottites. By compressio...

Introduction: A recent paper on helium loss from Martian meteorites states that the high-pressure mineralogy of veins is not a good equilibrium pressure barometer.[1] We respectfully disagree. However we do agree with the authors that it is likely that helium loss from Martian meteorites is largely due to shock metamorphism. It is not certain that the shock metamorphism was coincident with the ...

We report partial melting of an ultrahigh pressure eclogite in the Mesozoic Sulu orogen, China. Eclogitic migmatite shows successive stages of initial intragranular and grain boundary melt droplets, which grow into a three-dimensional interconnected intergranular network, then segregate and accumulate in pressure shadow areas and then merge to form melt channels and dikes that transport magma t...

This paper is a complement to the Tectonometamorphic Map of the Canadian Shield, and contains a brief description of the metamorphic history of Proterozoic orogenic belts and rock sequences in the Canadian Shield in Ontario, with a focus on rocks of the Southern and Grenville provinces. Metamorphism in the Southern Province has generally been attributed to the Penokean orogeny (~1879–1820 Ma), ...