Video Experimental Relacionado
Updated: Jul 11, 2026
11:50
Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions
Published on: June 13, 2015
El antiguo manto en un arco moderno: los isótopos de osmio en izu-bonin-mariana forearc peridotites
Parkinson1, Hawkesworth, Cohen
1Department of Earth Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA, UK.
Science (New York, N.Y.)
|September 25, 1998
Resumen
Los isótopos de osmio en peridotitas del manto del arco frontal Izu-Bonin-Mariana revelan antiguos eventos de agotamiento. Estos hallazgos sugieren que las zonas de subducción pueden preservar evidencia de la fusión temprana del manto, lo que afecta nuestra comprensión de la convección del manto superior.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Petrología Petrología.
- Geología de Isótopos Geología de Isótopos.
Sus antecedentes:
- Las peridotitas del manto proporcionan información sobre la composición y evolución del manto de la Tierra.
- Los isótopos de osmio (Os) son trazadores sensibles de los procesos del manto debido a la naturaleza altamente siderófila de Os y sus isótopos de larga vida.
Objetivo del estudio:
- Para investigar la composición isotópica del osmio en peridotitas del manto del arco frontal Izu-Bonin-Mariana.
- Determinar las implicaciones de estas firmas isotópicas para la comprensión de los antiguos eventos de fusión del manto y los procesos de la zona de subducción.
Principales métodos:
- Análisis de las proporciones de isótopos de osmio (187Os/188Os) en muestras de peridotita del manto.
- Cálculo de las edades del modelo Proterozoico basado en datos de isótopos de osmio.
- Comparación de las composiciones de peridotita con las fuentes de basalto de la cresta oceánica media (MORB).
Principales resultados:
- Las peridotitas exhiben proporciones no radiogénicas de 187Os/188Os, que van desde 0.1193 hasta 0.1273.
- Estas proporciones arrojan modelos de edades del Proterozoico entre hace 820 y 1230 millones de años.
- La fuente de manto agotado indicada por estas peridotitas está significativamente más agotada en elementos incompatibles que la fuente MORB.
Conclusiones:
- Los isótopos de osmio en las peridotitas del forearc registran antiguos eventos de fusión en el manto superior convectivo, anteriores al inicio reciente de la subducción.
- Las zonas de subducción actúan como depósitos de material antiguo y agotado del manto.
- Porciones del manto superior convectivo pueden poseer menos composiciones radiogénicas de isótopos de osmio de lo que se había deducido anteriormente.
Videos de Conceptos Relacionados
01:12Isotopes
Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.An element's atomic mass, or weight, is a...
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...
01:21Isothermal Processes
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:31Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
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.