The CI and CI-like chondrites provide a record of aqueous alteration in the early solar system. However, the CI-like chondrites differ in having also experienced a late stage period of thermal metamorphism. In order to constrain the nature and extent of the aqueous and thermal alteration, we have investigated the bulk mineralogy and abundance of H2O in the CI and CI-like chondrites using thermo...

The determination of metamorphic conditions is critical to the understanding of the formation of mountain belts. However, all collisional mountain belts contain large volumes of accreted sediments generally lacking metamorphic index minerals and are therefore not amenable to conventional petrologic investigations. By contrast, these units are often rich in carbonaceous material, making it possi...

Historically, dry-snow metamorphism has been classified by the thermal environment and thermodynamic processes in a snowpack. Snow experiencing predominantly macroscopic isothermal conditions develops different microstructure than snow subjected to large temperature gradients. As such, much previous research has been categorized by and limited to specific thermal conditions. The current researc...

Introduction: The source and duration of the heating event responsible for eucrite metamorphism is not well constrained. Three hypotheses have been proposed for the source of heat: Impact, conduction from the mantle, and rapid production of successive flows [1]. Textural and chemical relationships of noncumulate eucrites are investigated to constrain the thermal and temporal conditions responsi...

Introduction: CK carbonaceous chondrites are the only group of carbonaceous chondrites that exhibit thermal metamorphism. As a result, CKs display features of metamorphism such as silicate darkening, recrystallization and shock veins. Calcium Aluminum Inclusions and Fe-Ni metal are rare. Type Chondrule Opaque CAI's Matrix MET01149,11 3 25.0 7.0 2.0 66.0 EET99430,5 4 5.1 3.5 4.7 86.7 QUE99679,7 ...

We present a comprehensive description of petrologic, chemical and spectroscopic features of thermally metamorphosed CI-like and CM (and CM-like) chondrites. Only two such CI chondrites have so far been discovered i.e. Y-86029 and Y82162. Thermal metamorphism in these chondrites is apparent in their low contents of H2O, C and the most thermally labile trace elements, partial dehydration of matr...