Video Experimental Relacionado
Updated: Jul 11, 2026
09:41
Isolation of Quartz Grains for Optically Stimulated Luminescence (OSL) Dating of Quaternary Sediments for Paleoenvironmental Research
Published on: August 2, 2021
Cuarzo sacudido en el límite triásico-jurásico en Italia
Science (New York, N.Y.)
|January 24, 1992
Resumen
Se produjeron múltiples impactos al final del período Triásico, evidenciado por granos de cuarzo chocado encontrados en lechos de esquisto italiano. Estos impactos coinciden con la extinción de la fauna de los Rhaetavicula.
Área de la Ciencia:
- Geología Geología Geología.
- Paleontología Paleontología.
- Ciencias planetarias Ciencias planetarias.
Sus antecedentes:
- El evento de extinción de finales del Triásico es una gran extinción masiva.
- Comprender los desencadenantes de esta extinción es crucial para las reconstrucciones paleoclimáticas y paleoambientales.
Objetivo del estudio:
- Para investigar posibles eventos de impacto en el límite Triásico-Jurásico.
- Para analizar el cuarzo de choque en formaciones geológicas italianas.
Principales métodos:
- Examen microscópico de granos de cuarzo para las características de deformación plana.
- Análisis estratigráfico de los lechos de esquisto en los Apeninos del Norte.
- Análisis petrográfico de cuarzo sacudido.
Principales resultados:
- Grano de cuarzo metamorfoseado por choque identificado en tres capas de esquisto distintas.
- Características de deformación plana observadas en el 5-10% de los granos de cuarzo.
- La posición estratigráfica de las capas de cuarzo sacudido se correlaciona con la terminación de la fauna de Rhaetavicula.
Conclusiones:
- La evidencia sugiere al menos tres eventos de impacto muy espaciados al final del Triásico.
- Estos impactos pueden haber contribuido a los cambios ambientales en el límite Triásico-Jurásico.
- Se necesitaban más investigaciones para confirmar el origen extraterrestre y el momento preciso de los impactos.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:15Quarrying of Stone
Quarrying is the process of extracting stone from a quarry, where specialized techniques are employed to remove large blocks of stone safely and efficiently. This process can involve controlled explosions or more precision-oriented methods such as cutting and drilling.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the block.
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
01:26Minerals
Minerals are essential nutrients that the human body needs in small amounts to work properly. They play a vital role in many bodily functions, such as building strong bones and transmitting nerve impulses. Some minerals are needed for hormone production or to maintain a normal heartbeat. Major minerals include calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium, while trace minerals include iron, manganese, copper, iodine, zinc, cobalt, fluoride, and selenium.
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
01:21Pozzolans
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is a...
Fly ash is a...
01:33Cleavage and Blastulation
After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage is a mitotic cell division that does not result in growth. With each round of successive cell division, daughter cells get increasingly smaller.