The mineral Davemaoite (CaSiO3-perovskite, the third most abundant mineral in lower mantle layer of Earth's interior) has been discovered on the surface of the Lupa for the first time. It was found trapped inside a diamond. Perovskite is found naturally ONLY in lower mantle layer of the interior of the Lupa under extremely high temperature and pressure conditions. This first-ever discovery of interior lupa mineral in nature is important to geology for better understanding of dynamics of deep Lupa.
Ang perovskite ay isang mineral na binubuo ng calcium titanium oxide (CaTiO3). Ang anumang iba pang mineral na may katulad na istraktura ng kristal ay tinatawag na perovskite. Ginagawa nitong isang klase ng mga compound ang perovskite na may parehong uri ng istraktura ng kristal bilang CaTiO3 (istraktura ng perovskite).
Calcium-silicate perovskite (CaSiO3-perovskite o CaPv) ay isang mahalagang mineral dahil ito ang pangatlo sa pinakamaraming mineral1 (7% sa dami) sa ibabang layer ng mantle ng Earth's interior and plays a significant role in the heat dynamics of Earth's interior. To put things in perspective, of the three layers of Lupa, the mantle layer, between dense super-heated core and thin outer crust layer, makes up 84% of Earth's total volume while the lower mantle layer alone comprises 55 percent of the Lupa and extends from 670 and 2900 km in depth. The below table gives a snapshot view of place of perovskite in Earth's panloob.
Talahanayan: Lugar ng perovskite rich layer sa loob ng Earth
Perovskites along with other minerals in the mantle layer play a key role in the dynamics of deep lupa involving heat transfer from core towards surface, called mantle convection. Despite its abundance and importance, perovskite has never been retrieved from the lower mantle layer, because it loses its structure on being removed from its high-pressure conditions.
Researchers have now reported pagkatuklas of calcium silicate perovskite as a diamond inclusion in a natural sample. The diamond was found in Orapa mine, Botswana decades ago and was purchased by a mineralogist of USA in 1987. The team of researchers had been studying the diamond for few years for any entrapped deep-Lupa mineral
Ang pangkat ng pananaliksik na pinamumunuan ni Oliver Tschauner ay gumamit ng synchrotron x-ray diffraction upang pag-aralan ang panloob na istraktura ng napakaliit na madilim na specks sa isang brilyante na inaakalang perovskite mula sa mas mababang layer ng mantle at nakahanap ng tiyak na ebidensya ng structurally preserved cubic CaSiO3-perovskite doon2.
Further structural and chemical studies indicated that the mineral had large amounts of trapped potassium implying that this perovskite could host three of the major heat-producing elements (uranium and thorium were previously known) which influence heat generation in Earth's interior. They named the mineral “davemaoite” (after geophysicist Ho-kwang “Dave” Mao) which was approved as a new natural mineral. The researchers think that the mineral may have originated from lower mantle layer between 650 and 900 km deep below the Earth’s surface 3,4.
Nakakagulat, ang CaSiO3 perovskite was reported to be discovered in a deep-Earth diamond from South Africa in 2018 however the research team had not claimed official discoveryhttps://www.scientificeuropean.co.uk/sciences/biology/discovery-of-nitrogen-fixing-cell-organelle-nitroplast-in-a-eukaryotic-algae/ of a new mineral 5.
Ang pagtuklas na ito, kasabay ng mga karagdagang pagtuklas ng mas maraming mineral sa hinaharap, ay dapat pagyamanin ang pag-unawa sa ebolusyon ng mantle ng Earth.
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Sanggunian:
- Zhang Z., et al 2021. Thermal conductivity ng CaSiO3 perovskite sa mas mababang kondisyon ng mantle. Pisikal na Pagsusuri B. Tomo 104, Isyu 18 – 1. Na-publish noong 4 Nobyembre 2021. DOI: https://doi.org/10.1103/PhysRevB.104.184101
- Fei,Y. 2021. Nakuha ang Perovskite mula sa lower mantle, Science. Na-publish noong Nob 11, 2021. Vol 374, Isyu 6569 pp. 820-821. Agham (2021). DOI: https://doi.org/10.1126/science.abm4742
- Tschauner, O. et al. Pagtuklas ng davemaoite, CaSiO3-perovskite, bilang isang mineral mula sa ibabang mantle. Agham. 11 Nob 2021. Vol 374, Isyu 6569 pp. 891-894. DOI: https://doi.org/10.1126/science.abl8568
- Unibersidad ng Nevada 2021. Balita - Pananaliksik sa Maikling: Kauna-unahang Interior Earth Mineral na Natuklasan sa Kalikasan. [Na-post noong Nobyembre 15, 2021. Magagamit online sa https://www.unlv.edu/news/release/research-brief-first-ever-interior-earth-mineral-discovered-nature
- Nestola, F., Korolev, N., Kopylova, M. et al. Ang CaSiO3 perovskite sa brilyante ay nagpapahiwatig ng pag-recycle ng oceanic crust sa ibabang mantle. Kalikasan 555, 237–241 (2018). https://doi.org/10.1038/nature25972
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