Results 41 to 50 of about 729 (236)

Variations in the P‐T‐t of Deformation in a Crustal‐Scale Shear Zone in Metagranite

Geochemistry, Geophysics, Geosystems, 2020
Deformation in crustal‐scale shear zones occurs over a range of pressure‐temperature‐time (P‐T‐t) conditions, both because they may be vertically extensive structures that simultaneously affect material from the lower crust to the surface, and because ...
T. K. Cawood, J. P. Platt
doaj   +1 more source

New Magnetite Reference Material for SIMS δ18O Measurements and a Study of Precision and Accuracy Due to Crystal Orientation Effects

Geostandards and Geoanalytical Research, EarlyView.
Key Points A new magnetite reference material (PF21mt) is available for δ18O measurements by SIMS. Reproducibility of measurement results in two laboratories suggest orientation bias of ±2‰ (2s) at 20 keV. Repeatability improves to ±1‰ (2s) when using a 13 keV protocol, suggesting reduced orientation bias. In situ isotope ratio measurements provide the
Michelle Ulrich, Daniela Rubatto, Maria Rosa Scicchitano, Benita Putlitz, Thomas Bovay   +4 more
wiley   +1 more source

Controlling factors of coal petrology, coal quality, and coal type characteristics and classification of genesis types of special coal in Ningxia

Meitan kexue jishu
Promoting the transition of coal resources from fuel to both fuel and raw material, and achieving clean and efficient utilization of coal are crucial approaches to addressing energy, resource, and environmental challenges in the 21st century.
Yingchun WEI, Xin WANG, Xiaoyan JI, Daiyong CAO, Yongping LIANG, Xin LI, Jingqi LI, Wenhao ZHU   +7 more
doaj   +1 more source

Igneous and Metamorphic Petrology

Eos, Transactions American Geophysical Union, 1983
So many new and exciting topics in petrology have appeared over the last several years that it has become difficult to find a text that deals adequately with fundamentals as well as current topics; the present book may be one of the better texts in its field today because it achieves this combination with clarity and appropriate emphasis.
openaire   +1 more source

Wild bee diversity and land use: A case study in a mountain agroecosystem of the Serranía de Ronda, southern Spain

Insect Conservation and Diversity, EarlyView.
Orchards supported the highest wild bee diversity and functional diversity, highlighting their role in maintaining bee communities in Mediterranean agroecosystems. Landscape heterogeneity positively influenced functional evenness and dispersion of wild bee communities, underscoring the importance of diverse landscapes for bee conservation. The presence
Violeta Hevia, Francisco M. Azcárate, Jorge Chicote, Federica Ravera   +3 more
wiley   +1 more source

Jadeite in Continental Subduction: Its Preservation, Breakdown and Pseudomorphic Replacement in Erzgebirge UHP Gneisses

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The absence of jadeite in regions where subduction of continental crust has been documented by other high‐pressure (HP) or ultrahigh‐pressure (UHP) minerals is striking. This study presents only the second discovery of jadeite in the crystalline rocks of the Erzgebirge, a region known for its occurrences of microdiamond, coesite and omphacite ...
Ondrej Lexa, Martin Racek, Petr Jeřábek, Benjamin Paddon   +3 more
wiley   +1 more source

Metamorphic Inheritance, Lower‐Crustal Earthquakes, and Continental Rifting

Geochemistry, Geophysics, Geosystems
The Malawi Rift is localized within Precambrian amphibolite‐granulite facies metamorphic belts, bounded by up to 150 km long border faults, and generates earthquakes throughout ∼40 km thick crust.
Å. Fagereng, J. F. A. Diener, C. J. Tulley, B. Manda   +3 more
doaj   +1 more source

Variable Sr Diffusion and Implications for Rb–Sr Biotite Geochronology

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The rubidium–strontium (Rb–Sr) system has a long pedigree as a geochronological tool that relies on the application of an isochron approach. In particular, biotite contains strongly radiogenic Rb–Sr isotopes, and thus can yield meaningful crystallisation or cooling ages via this approach. However, the response of the Rb–Sr system in biotite to
Riley Rohrer, Christopher L. Kirkland, Hugo Olierook, Tim Johnson, Katy Evans   +4 more
wiley   +1 more source

Geochemistry and petrogenesis of the Kolah-Ghazi granitoid assemblage, south of Esfahan

Journal of Economic Geology, 2018
Introduction The Kolah-Ghazi granitoid assemblage is located in the south of Esfahan and in the Sanandaj-Sirjan magmatic-metamorphic zone. The Sanandaj-Sirjan zone is extended for 1500 km from Sirjan in the southeast to Sanandaj in the northwest of Iran
Jamshid Ahmadian, Hajar Gholamian, Ali Khan Nasr Esfahani, Maryam Honarmand   +3 more
doaj   +1 more source

Vertical profiling of shock attenuation at the Rochechouart impact structure, France

Meteoritics &Planetary Science, EarlyView.
Abstract Rochechouart, south‐west France, is a complex impact structure. Here, we present the first report of shock barometry of quartz from what are likely parautochthonous basement units at depth, based on samples from the 2017 C.I.R.I.R drilling campaign. The crystallographic orientations of 725 sets of PDFs in 512 quartz grains in samples from four
P. Struzynska, S. Alwmark, C. Alwmark, M. H. Poelchau, P. Lambert   +4 more
wiley   +1 more source