Results 61 to 70 of about 1,649 (213)

Search for impact ejecta at the Paleocene–Eocene boundary

Meteoritics &Planetary Science, EarlyView.
Abstract Almost 10 years have passed since microtektites and microkrystites were reported for the Paleocene–Eocene (P–E) boundary in drill cores and outcrop in New Jersey and in ODP Hole 1051B in the western North Atlantic. The glassy spherules were interpreted to reflect an impact trigger for the Paleocene–Eocene Thermal Maximum (PETM).
Birger Schmitz, Yue Cai, Shiyong Liao, Victoriano Pujalte, Ting Ruan, Robert P. Speijer, Ellen Thomas   +6 more
wiley   +1 more source

Observation Operators and Cosmology [PDF]

Indiana University Mathematics Journal, 1969
openaire   +2 more sources

A geophysical investigation of the Roter Kamm impact crater, Namibia

Meteoritics &Planetary Science, EarlyView.
Abstract The Roter Kamm impact crater is located in the southern Namib Desert. The crater has a diameter of 2.5 km and belongs to the category of simple, bowl‐shaped impact craters, with an elevated rim of fractured target rock. The crater's interior is completely buried beneath sediments, preventing extensive surface investigations of the bedrock ...
Hannah Nienhaus, Pritam Yogeshwar, Wiebke Mörbe, Bülent Tezkan, Yajun Liu, Bufelo Lushetile, Martin Melles   +6 more
wiley   +1 more source

Static recrystallization of shocked calcite in Ries impact breccias

Meteoritics &Planetary Science, EarlyView.
Abstract Calcite is prone to chemical and microstructural modifications, especially after having been strained at high stresses and strain rates, as during hypervelocity impact events. These modifications include precipitation from pore fluid as well as replacement of strained volumes by recrystallization. In calcite aggregates of a metagranite breccia
Claudia A. Trepmann, Fabian Dellefant, Lina Seybold, Wolfgang W. Schmahl, Elena Sturm, Daniel Weidendorfer, Sandro Jahn, Iuliia V. Sleptsova, Stuart A. Gilder   +8 more
wiley   +1 more source

Microbial Endolithic Community at Meteor Crater

Meteoritics &Planetary Science, EarlyView.
Abstract Postimpact recovery and evolution in response to climate changes produced a modern ecosystem at Meteor Crater dominated by a grassland and woodland of piñon and juniper, which has been used to evaluate floral and megafaunal consequences of impact cratering during the Phanerozoic Eon of complex life.
David A. Kring, Charles S. Cockell
wiley   +1 more source

Confirmation of the impact origin of the Late Ordovician Tvären impact structure (southeast Sweden) and emplacement of impactites in a marine setting

Meteoritics &Planetary Science, EarlyView.
Abstract The Tvären structure in southeastern Sweden has been listed as a confirmed marine‐target impact structure for decades. However, to date, no measurements and/or indexed data of planar deformation features in quartz grains from the structure have been published or any other unequivocal evidence of impact.
Katarzyna J. Gajewska, Sanna Alwmark, Mikael Calner, Sylvain Richoz, Jens Ormö, Erik Sturkell, Carl Alwmark   +6 more
wiley   +1 more source

“We Have Come to Offer Something Which (They) Were Not Even Looking for”: U.S. Christian Conservative Evangelical Faith Missions in the Ecuadorian Upper Amazon

The Journal of American Culture, EarlyView.
Diego Mauricio Cortés
wiley   +1 more source

Polymict melt‐bearing breccia dikes in the Morokweng impact structure formed by slip‐induced mechanical mixing of pseudotachylite and cataclasite along large‐displacement impact faults

Meteoritics &Planetary Science, EarlyView.
Abstract A core drilled through shocked and faulted Archean granitoid gneisses and dolerites in the eroded peak ring of the 70–80 km diameter Morokweng impact structure intersects multiple centimeter‐ to meter‐wide clastic‐matrix breccias containing a polymict clast population of lithic and mineral clasts and altered, millimeter‐ to centimeter ‐size ...
Roger L. Gibson, S'lindile S. Wela, Leonidas C. Vonopartis, Marco A. G. Andreoli   +3 more
wiley   +1 more source

Confirming the impact origin of the São Miguel do Tapuio structure, northeastern Brazil

Meteoritics &Planetary Science, EarlyView.
Abstract The São Miguel do Tapuio structure (SMT) is a remarkable, nearcircular feature of about 21 km diameter, centered at 5°37.6′ S, 41°23.3′ W in Piauí state, northeastern Brazil. The structure is located within the sedimentary strata of the Paleozoic–Mesozoic Parnaíba Basin and predominantly comprises sandstones of the Devonian Pimenteiras and ...
Alvaro Penteado Crósta, Neivaldo Araújo de Castro, Marcos Alberto Rodrigues Vasconcelos, Airton Natanael Coelho Dias, Ludovic Ferrière, Wolf Uwe Reimold, Ana Maria Góes, Jackson Alves Martins, Liliana Sayuri Osako, Raimundo Mariano Gomes Castelo Branco   +9 more
wiley   +1 more source

An unsupervised machine learning approach to iron meteorite classification

Meteoritics &Planetary Science, EarlyView.
Abstract Iron meteorites are usually classified manually using bivariate elemental plots. This study extends iron meteorite classification into multi‐element space. We present a computational method for the classification of iron meteorites by applying unsupervised machine learning using density‐based cluster analysis.
Louis‐Alexandre Lobanov, Hilary Downes
wiley   +1 more source