Video Experimental Relacionado
Updated: Jul 12, 2026
06:06
Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod
Published on: August 17, 2016
Sm-nd y rb-sr cronología de la formación de la corteza continental
Science (New York, N.Y.)
|June 2, 1978
Resumen
Los estudios geocronológicos que utilizan isótopos de samario-neodimio y rubidio-estroncio revelan que las provincias Superior, Slave y Churchill del Escudo Canadiense se formaron hace entre 2.500 y 2.700 millones de años, lo que proporciona información sobre la evolución de la corteza continental.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Geología de Isótopos Geología de Isótopos.
- Geocronología Geocronología.
Sus antecedentes:
- Comprender la formación y evolución de la corteza continental es crucial para descifrar la historia geológica de la Tierra.
- La sistemática isotópica ofrece herramientas poderosas para la datación de materiales geológicos y el rastreo de sus orígenes.
Objetivo del estudio:
- Para determinar las edades de formación de segmentos específicos de la corteza continental.
- Para investigar la evolución geoquímica del Escudo Canadiense.
Principales métodos:
- Utilizando una sistemática isotópica de samario-neodimio (Sm-Nd) y rubidio-estroncio (Rb-Sr).
- Analizando muestras compuestas de las provincias estructurales Superior, Slave y Churchill del Escudo Canadiense.
- Aplicación de hipótesis plausibles con respecto a la evolución geoquímica de la corteza continental.
Principales resultados:
- Las provincias estructurales Superior, Esclavo y Churchill del Escudo Canadiense se formaron en el período de hace 2.5 a 2.7 mil millones de años (eones).
- El sistema isotópico de samario-neodimio en rocas sedimentarias parece estar en gran parte inalterado durante la sedimentación y la diagenesis, lo que permite una determinación fiable de la edad de procedencia.
Conclusiones:
- Las principales provincias estructurales del Escudo Canadiense tienen un rango de edad de formación coherente.
- La datación samario-neodimio de sedimentos es un método viable para determinar la edad de las procedencias de los sedimentos, lo que contribuye a nuestra comprensión de la evolución de la corteza terrestre.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:48Radioactive Decay and Radiometric Dating
Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
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...
03:18Nuclear Stability
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
To hold positively charged protons together in the...
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.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:27Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...