. | . |
Iron-rich meteorites show record of core crystallization in system's oldest planetesimals by Staff Writers Washington DC (SPX) Aug 07, 2020
New work led by Carnegie's Peng Ni and Anat Shahar uncovers new details about our Solar System's oldest planetary objects, which broke apart in long-ago collisions to form iron-rich meteorites. Their findings reveal that the distinct chemical signatures of these meteorites can be explained by the process of core crystallization in their parent bodies, deepening our understanding of the geochemistry occurring in the Solar System's youth. They are published by Nature Geoscience. Many of the meteorites that shot through our planet's atmosphere and crashed on its surface were once part of larger objects that broke up at some point in our Solar System's history. The similarity of their chemical compositions tells scientists that they originated as part of common parent bodies, even if they arrived here centuries apart and in vastly different locations. Deciphering the geologic processes that shaped these parent bodies could teach us more about our Solar System's history and Earth's formative years. To truly understand what makes our planet capable of sustaining life, and to look for habitable worlds elsewhere, it is crucial to understand its interior - past and present. "Like our Solar System's rocky planets, these planetesimals accreted from the disk of dust and gas that surrounded our Sun in its youth," explained lead author Ni. "And like on Earth, eventually, the densest material sank toward the center, forming distinct layers." Iron meteorites were thought to be the remnants of the cores of their ancient, broken-apart parent bodies. "A history of how their layers differentiated is recorded in their chemical makeup, if we can read it," said Shahar. There are four stable isotopes of iron. (Each element contains a unique number of protons, but its isotopes have varying numbers of neutrons.) This means that each iron isotope has a slightly different mass than the others. As a result, some isotopes are preferred by certain chemical reactions - which, in turn, affects the proportion of that isotope in the reaction's end products. The traces of this favoritism can be found in rock samples and can help elucidate the processes that forged these meteorite parent bodies. Previous research on the ratios of iron isotopes in iron meteorites led to a puzzling observation: compared to the raw material from which their parent bodies were constructed, they are enriched in heavy isotopes of iron. Together with Nancy Chabot and Caillin Ryan of the Johns Hopkins University Applied Physics Laboratory, Ni and Shahar determined that this enrichment can be explained entirely by the crystallization of a parent object's core. The researchers use lab-based mimicry to simulate the temperatures of core crystallization in iron meteorite parent bodies. Sophisticated models of the crystallization process including other elemental concentrations - for example, of gold and iridium, as well as isotopes of iron - confirmed their findings. "This improved understanding of core crystallization adds to our knowledge about our Solar System's formative period," Ni concluded.
New technique enables mineral ID of precious Antarctic micrometeorites Tokyo, Japan (SPX) Jul 29, 2020 The composition of Antarctic micrometeorites and other tiny but precious rocks such as those from space missions - is really hard to analyze without some sample loss. But a new technique should make it easier, cheaper and faster to characterize them while preserving more of the sample. The findings were published on the peer reviewed journal Meteoritics and Planetary Science on May 21. Some 40,000 tons of micrometeorites, less than a millimeter in diameter, bombard the earth every year. Analyzing ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |