A study of the shocked Coconino sandstone from Meteor Crater, Arizona, was undertaken to examine the role of porosity in the compression of rocks and in the formation of highpressure phases. A suite of shocked Coconino. specimens collected at the crater is divided into five classes, arranged in .order of decreasing quartz content. The amounts of coesite, stishovite (measured by quantitative X-r...

The study area is located about 110 kilometers southeast of Mashhad and approximately 40 kilometers southeast of Fariman. The area is considered to be a part of the central Iran zone. It includes metamorphic rocks with different protoliths consisting of pelitic, carbonate and quartz - feldspathic rocks. The metamorphism in the study area is considered to be a contact regional metamorphism with ...

Observations on shocked quartz in Cretaceous-Tertiary (K-T) boundary sediments compellingly tied to Chicxulub crater raise three problems. First, in North America shocked quartz occurs above the main K-T ejecta layer. Second, shocked quartz is more abundant west than east of Chicxulub. Third, shocked quartz reached distances requiring initial velocities up to 8 kilometers per second, correspond...

Abstract This study describes mineralogical and crystallochemical characteristics of metamorphic tourmalines from an Alpine shear zone in a Variscan rock sequence the Maramures region northern part East Carpathians. We use this mineral to unravel aspects evolution tourmaline bearing host rocks compare crystallo-chemical other Alps. Petrographic microstructural observations, as well electron mic...

Abstract. Permeability of crystalline rocks depends on parameters such as density and interconnectivity fractures pores. While in pristine porosity is usually considered to be low, low-grade solution phenomena the formation episyenites occur occasionally may cause a local dramatic increase permeability. These can effective otherwise unaltered result preferential removal certain mineral phases, ...

Abstract New investigations of petrographic and geochemical characteristics Mesozoic sandstones from the northwestern Gulf Suez in Egypt have been undertaken, documenting dominance quartzose containing on average ~ 5% mostly sedimentary subordinately metamorphic lithic fragments (siltstone, sandy siltstone, and, more rarely slate, metasiltstone, limestone, dolostone, quartz-muscovite schist, gn...

A gas sensor based on off-beam quartz enhanced photoacoustic spectroscopy was developed and optimized. Specifically, the length and diameter of the microresonator tube were optimized, and the outer tube shape is modified for enhancing the trace gas detection sensitivity. The impact of the distance between the quartz tuning fork and an acoustic microresonator on the sensor performance was experi...