Related Experiment Video
Updated: Jul 12, 2026
11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Pyroxene-garnet transformation in coorara meteorite.
Science (New York, N.Y.)
|May 15, 1970
Summary
Majorite, a new garnet found in the Coorara meteorite, likely formed from pyroxene, not olivine. Similarities between Coorara and Tenham meteorites suggest they originated from a common parent body.
Area of Science:
- Mineralogy
- Cosmochemistry
- Petrology
Background:
- The Coorara meteorite contains a novel garnet, majorite.
- Previous hypotheses suggested majorite's origin from olivine.
Purpose of the Study:
- To investigate the mineralogy and chemical composition of majorite in the Coorara meteorite.
- To determine the precursor mineral for majorite formation.
- To compare the Coorara meteorite with other meteorites.
Main Methods:
- Chemical analysis of majorite and associated minerals.
- Mineralogical characterization using microscopy and spectroscopy.
- Comparative analysis of meteorite textures and compositions.
Main Results:
- Majorite's chemical composition indicates derivation primarily from pyroxene.
- Silicon was observed in sixfold coordination within the majorite structure.
- Ringwoodite, an olivine-composition spinel, was identified within a garnet matrix.
- Similarities in mineralogy and texture between the Coorara and Tenham meteorites were noted.
Conclusions:
- The formation of majorite in the Coorara meteorite is linked to pyroxene.
- The presence of ringwoodite and majorite suggests specific high-pressure transformation conditions.
- The mineralogical parallels between Coorara and Tenham support the hypothesis of a shared parent body for these meteorites.
More Related Videos
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
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.
02:33Phase Transitions: Sublimation and Deposition
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
03:20Nuclear Transmutation
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed protons being...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...