| Lodranite | |
|---|---|
| — Group — | |
 Lodranite meteorites found at Queen Alexandra Range | |
| Compositional type | Stony |
| Type | Achondrite |
| Class | Primitive achondrite |
| Composition | Meteoric iron, Olivine, Pyroxene |
Lodranites are a small group of primitive achondrite meteorites that consists of meteoric iron and silicate minerals. Olivine and pyroxene make up most of the silicate minerals. Like all primitive achondrites lodranites share similarities with chondrites and achondrites. [1]
The lodranite group is named after Lodhran, Pakistan, where the type specimen fell on 1 October 1868 at 14:00. [2] Eyewitnesses of the fall reported a loud bang accompanied by a rising dust cloud to the east of the city, which led to the discovery and retrieval of the meteorite. [3] [4] The "meteorite from Lodran" was first described by Gustav Tschermak in 1870. [3] He described the meteorite being "apart from the nickel-iron it is an olivine-bronzite aggregates of such outstanding sort, that has never been found in a meteorite before only similar to the terrestrial olivine rock ". George Thurland Prior was the first to classify the lodran meteorite as the only member of the lodranite group. He also saw close similarities to the ureilites. [5]
Lodranites are primitive achondrites. They are coarser grained than acapulcoites. The main mineral phases are low calcium pyroxene and olivine with minor amounts of plagioclase and troilite. Because of their composition they are related to the chondrites and H class chondrites. [6] Lodranites can be described as chondrites that were heated to the point where FeNi and FeS reach an eutectic point. At this point partial melting occurred and some of the metal- and silica melt was removed. [6]
The Lodran meteorite is described as having roughly equal amounts of metal, olivine and pyroxene which make up most of the volume. Other minerals include sulphide, chromite, phosphide and chrome-diopside. [7]
The lodranites and acapulcoites share the same parent body which was probably similar to an S-type asteroid. The lodranites are coarser grained and yield higher temperatures with isotopic methods and are therefore thought to be from greater depths within the parent body. [2]
The cooling path of the parent body can be reconstructed by using radiometric dating. The Hf-W system in high-Ca pyroxenes has a closing temperature in between 975 and 1025 °C. The parent body cooled under this temperature between 4563.1 and 4562.6 million years ago. This means that the parent body accreted about 1.5 to 2 million years after the CAI formation. [8] Trace elements indicate that the parent body had a complex geologic history with partial melting, melt migration and metasomatism. [9]
In meteoritics, a meteorite classification system attempts to group similar meteorites and allows scientists to communicate with a standardized terminology when discussing them. Meteorites are classified according to a variety of characteristics, especially mineralogical, petrological, chemical, and isotopic properties.
A chondrule is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites represent one of the oldest solid materials within the Solar System and are believed to be the building blocks of the planetary system, it follows that an understanding of the formation of chondrules is important to understand the initial development of the planetary system.
A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet’s gravity well become the most common type of meteorite by arriving on a trajectory toward the Earth’s surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%.
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes.
Meteoritics is the science that deals with meteors, meteorites, and meteoroids. It is closely connected to cosmochemistry, mineralogy and geochemistry. A specialist who studies meteoritics is known as a meteoriticist.
The LL chondrites are a group of stony meteorites, the least abundant group of the ordinary chondrites, accounting for about 10–11% of observed ordinary-chondrite falls and 8–9% of all meteorite falls. The ordinary chondrites are thought to have originated from three parent asteroids, with the fragments making up the H chondrite, L chondrite and LL chondrite groups respectively. The composition of the Chelyabinsk meteorite is that of a LL chondrite meteorite. The material makeup of Itokawa, the asteroid visited by the Hayabusa spacecraft which landed on it and brought particles back to Earth also proved to be type LL chondrite.
George Thurland Prior FRS was a British mineralogist. He made great contributions to mineralogical chemistry, petrology and meteoritics.
Primitive achondrites are a subdivision of meteorites. They are classified on the same rank and lying between chondrites and achondrites. They are called primitive because they are achondrites that have retained much of their original chondritic properties. Very characteristic are relic chondrules and chemical compositions close to the composition of chondrites. These observations are explained as melt residues, partial melting, or extensive recrystallization.
Winonaites are a group of primitive achondrite meteorites. Like all primitive achondrites, winonaites share similarities with chondrites and achondrites. They show signs of metamorphism, partial melting, brecciation and relic chondrules. Their chemical and mineralogical composition lies between H and E chondrites.
Acapulcoites are a group of the primitive achondrite class of stony meteorites.
IAB meteorites are a group of iron meteorites according to their overall composition and a group of primitive achondrites because of silicate inclusions that show a strong affinity to winonaites and chondrites.
IIICD meteorites are a group of primitive achondrites. They are classified in a clan together with the IAB meteorites and the winonaites.
The Zakłodzie meteorite is a stony-iron meteorite found in Poland in 1998. Its mass is 8.68 kilograms (19.1 lb). It is composed predominantly from enstatite and meteoric iron. Currently classified as an ungrouped enstatite achondrite its classification is still an ongoing scientific debate.
The Itqiy meteorite is an enstatite-rich stony-iron meteorite. It is classified as an enstatite chondrite of the EH group that was nearly melted and is therefore very unusual for that group. Other classifications have been proposed and are an ongoing scientific debate.
Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron.
Nonmagmatic meteorite is a deprecated term formerly used in meteoritics to describe iron meteorites that were originally thought to have not formed by igneous processes, to differentiate them from the magmatic meteorites, produced by the crystallization of a metal melt. The concept behind this was developed in the 1970s, but it was quickly realized that igneous processes actually play a vital role in the formation of the so-called "nonmagmatic" meteorites. Today, the terms are still sometimes used, but usage is discouraged because of the ambiguous meanings of the terms magmatic and nonmagmatic. The meteorites that were described to be nonmagmatic are now understood to be the product of partial melting and impact events and are grouped with the primitive achondrites and the achondrites.
This is a glossary of terms used in meteoritics, the science of meteorites.
Mason Gully is an ordinary chondrite of subclass H5, and is the second meteorite to be recovered using the Desert Fireball Network (DFN) camera observatory. One stone weighing 24.5g was observed to fall by the Desert Fireball Network observatory in Western Australia on 13 April 2010 at 10h36m10s UTC. It was recovered by the DFN on 3 November 2010 by Dr. R. Merle and the Fireball network recovery team, and was found 150m from its predicted fall location based upon the observed trajectory and calculated mass.
Asteroidal water is water or water precursor deposits such as hydroxide (OH−) that exist in asteroids. The "snow line" of the Solar System lies outside of the main asteroid belt, and the majority of water is expected in minor planets (e.g., Kuiper belt objects and Centaurs. Nevertheless, a significant amount of water is also found inside the snow line, including in near-earth objects.
CM chondrites are a group of chondritic meteorites which resemble their type specimen, the Mighei meteorite. The CM is the most commonly recovered group of the 'carbonaceous chondrite' class of meteorites, though all are rarer in collections than ordinary chondrites.