Video Experimental Relacionado
Updated: Jul 11, 2026

09:45
Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria
Published on: July 24, 2016
Osmio-187/osmio-186 en nódulos de manganeso y en el límite entre el Cretácico y el Terciario
Resumen
La proporción de osmio-187/osmio-186 en los sistemas planetarios evoluciona con el tiempo debido a la desintegración del renio-187. La Tierra La Tierra La Tierra La Tierra La Tierra
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Cosmoquímica es la cosmoquímica.
- Geología de Isótopos Geología de Isótopos.
Sus antecedentes:
- El decaimiento radiactivo del renio-187 (4,6 x 10^10 años) al osmio-187 influye en la proporción de osmio-187/osmio-186 en los sistemas planetarios.
- Esta relación es una función del tiempo y la relación inicial de renio-187/osmio-186, que varía en diferentes depósitos planetarios como el manto y la corteza.
Objetivo del estudio:
- Para investigar las proporciones de osmio-187/osmio-186 en varias muestras terrestres y marinas.
- Evaluar el origen del osmio en formaciones geológicas, particularmente en el límite entre el Cretácico y el Terciario.
Principales métodos:
- Análisis de las proporciones de osmio-187/osmio-186 en los meteoritos, el manto de la Tierra, la corteza continental, los nódulos de manganeso marino y las capas límite Cretácico-Terciario.
- Utilizando firmas isotópicas para rastrear la fuente y la evolución del osmio.
Principales resultados:
- Las proporciones típicas de meteorito y manto terrestre de renio-187/osmio-186 de ~3.2 dan como resultado una proporción actual de osmio-187/osmio-186 de ~1.1.
- Se espera que la corteza continental de la Tierra (relación de renio-187/osmio-186 ~400, edad 2 x 10^9 años) tenga una relación de osmio-187/osmio-186 de ~10.
- Los nódulos de manganeso marino muestran proporciones (6-8.4) consistentes con la entrada continental y el osmio del manto.
- Las capas límite entre el Cretácico y el Terciario exhiben bajas proporciones de osmio-187/osmio-186 (1,65 marino, 1,29 continental).
Conclusiones:
- Las proporciones de osmio-187/osmio-186 observadas en las capas límite entre el Cretácico y el Terciario sugieren un origen predominantemente meteorítico para el osmio.
- El análisis isotópico proporciona una poderosa herramienta para comprender las fuentes y la mezcla de materiales en la evolución planetaria.
Videos de Conceptos Relacionados
Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
Minerals
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.
Origin of Photosynthesis
Photosynthesis represents a fundamental biological process that transformed Earth's atmosphere and paved the way for complex life. Emerging roughly 3.4–3.8 billion years ago, the earliest photosynthetic organisms harnessed light energy to produce organic compounds. These anoxygenic phototrophs used electron donors like hydrogen sulfide (H₂S) or ferrous iron (Fe²⁺), rather than water, and did not release molecular oxygen (O₂) as a byproduct. Various groups, including green sulfur and purple...
Periodic Classification of the Elements
The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table, a periodic recurrence of similar electron configurations in the outer shells of these elements is observed. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom...
The 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...

