- CM chondrites are composed of about 70% fine-grained material (matrix), and most have experienced extensive aqueous alteration. The much studied Murchison meteorite, which fell in Australia in 1969, is the best-known member of this group.
- CO chondrites have only about 30% matrix and have experienced very little aqueous alteration. Most have experienced small degrees of thermal metamorphism.
What type of rock is chondrites?
Chondrite Meteorite is part sedimentary and part igneous . As the oldest rock in the Museum, it formed about 4.5 billion years ago. That's as old as Earth itself!
Where are chondrites formed?
the asteroid beltLike most meteorites, chondrites originated in the asteroid belt where collisions and gravitational perturbations put them into Earth-crossing orbits. (Ordinary chondrites, in particular, are from S-class asteroids.) Chondrites formed about 4.56 billion years ago as part of the formation of their parent asteroids.
How do you identify a chondrite?
Nickel Iron: Most chondrites contain tiny flecks of nickel iron sprinkled throughout. For this reason, meteorite hunters often use metal detectors in areas where meteorites are likely to be found. A chondrite's high nickel-iron content makes it adhere to a strong magnet.
How much is a chondrite meteorite worth?
Stones consist of ordinary chondrites, which sell for between $3 and $10 per gram. Carbonaceous chondrites fetch about $8 per gram and up.
Is chondrite magnetic?
Meteorites are not magnets – they do not attract paper clips or pins. Most (>95%) meteorites (chondrites, iron meteorites), however, do attract a magnet because they contain a lot of iron-nickel metal.
Are chondrites meteorites?
A chondrite /ˈkɒndraɪt/ 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.
What is the rarest meteorite?
The Winchcombe meteorite, aptly named after the Gloucestershire town where it landed, is an extremely rare type called a carbonaceous chondrite. It is a stony meteorite, rich in water and organic matter, which has retained its chemistry from the formation of the solar system.
How much is a 1 pound meteorite worth?
Meteorites are quite valuable, worth as much as $1,000 per gram, according to the LiveScience website. Kellyco Metal Detectors posted on eBay that it can sell for $300 per gram or more — meaning 1 pound could be worth $1 million. "Meteorites are rarer than gold, platinum, diamonds or emeralds.
What rocks are mistaken for meteorites?
Magnetite and Hematite- Often mistaken for meteorites because they are magnetic.
How do you tell if a rock is a meteorite?
Meteorites have several properties that help distinguish them from other rocks: Density: Meteorites are usually quite heavy for their size, since they contain metallic iron and dense minerals. Magnetic: Since most meteorites contain metallic iron, a magnet will often stick to them.
Are meteorites radioactive?
Are meteorites radioactive? No. Meteorites do contain radioactive elements, but not significantly more than any ordinary terrestrial rock.
Can you keep a meteorite?
Meteorites may be collected without a permit or collection fee. Casual collection is for personal use only, and therefore, cannot be bartered or sold for commercial purposes. Meteorites may be collected for scientific and educational purposes under a permit issued under the authority of the Antiquities Act.
Where was the chondrite meteorite found?
state of ChihuahuaThe Allende meteorite is the largest carbonaceous chondrite ever found on Earth. The fireball was witnessed at 01:05 on February 8, 1969, falling over the Mexican state of Chihuahua. After it broke up in the atmosphere, an extensive search for pieces was conducted and over 2 tonnes (2.2 tons) were recovered.
Where are tektites found?
Tektites have been found only in certain parts of the world, spread over large areas called strewn fields, mainly in low latitudes. The three major areas are south-east Asia (especially Thailand and the Philippines), Australasia; Caribbean-North America; and Ivory Coast, West Africa.
What is the difference between chondrites and achondrites?
There are two main types of stony meteorite: chondrites (some of the oldest materials in the solar system) and achondrites (including meteorites from asteroids, Mars and the Moon).
What is the primary difference between a chondrite and an Achondrite?
Whats the difference between a chondrite and an achondrite? Chondrites are a type of stony meteorite with chondrules, whereas achondrites are a type of stony meteorite that contain no chondrules.
What are chondrites made of?from en.wikipedia.org
The remainder of chondrites consists of fine-grained (micrometre-sized or smaller) dust, which may either be present as the matrix of the rock or may form rims or mantles around individual chondrules and refractory inclusions. Embedded in this dust are presolar grains, which predate the formation of our solar system and originated elsewhere in the galaxy. The chondrules have distinct texture, composition and mineralogy, and their origin continues to be the object of some debate. The scientific community generally accepts that these spheres were formed by the action of a shock wave that passed through the Solar System, although there is little agreement as to the cause of this shock wave.
What are the characteristics of chondrites?from en.wikipedia.org
Characteristics. Prominent among the components present in chondrites are the enigmatic chondrules, millimetre-sized spherical objects that originated as freely floating, molten or partially molten droplets in space; most chondrules are rich in the silicate minerals olivine and pyroxene .
How are chondrules formed?from sciencedirect.com
Chondrites contain a small fraction of chondrules that may have formed by impact on asteroids after they had accreted. One rare type of chondrule (~ 0.1%) in type 4–6 ordinary chondrite breccias is composed largely of plagioclase (or mesostasis of plagioclase composition) and chromite ( Krot et al., 1993 ). Krot and Rubin (1993) suggest that these chondrules may have formed by impact melting as they find impact melts with similar compositions inside shocked ordinary chondrites and such chondrules are absent in type 3 chondrites. In addition, some chromite-rich chondrules contain chromite-rich aggregates, which appear to be fragments of equilibrated chondrites. Other possible impact products were described in LL chondrites, which are mostly breccias, by Wlotzka et al. (1983). They found microporphyritic potassium-rich clasts with highly variable K/Na ratios that are totally unlike chondrules in type 3 chondrites. Large chondrules and clasts in Julesberg (L3) may also be impact melt products according to Ruzicka et al. (1998). More complex formation history, including lofting of partial melt from a differentiated body followed by reduction of FeO, metastable crystallization of olivine, reaccumulation into an insulating secondary body, and cumulate formation, was proposed for silica-rich igneous clasts in the Buzzard Coulee (H4) chondrite ( Ruzicka et al., 2012b ).
What does a chondrite number mean?from en.wikipedia.org
The chondrules in a chondrite that is assigned a "3" have not been altered. Larger numbers indicate an increase in thermal metamorphosis up to a maximum of 7, where the chondrules have been destroyed. Numbers lower than 3 are given to chondrites whose chondrules have been changed by the presence of water, down to 1, where the chondrules have been obliterated by this alteration.
How big are CR chondrites?from en.wikipedia.org
CR chondrites have chondrules that are similar in size to those in ordinary chondrites (near 1 mm), few refractory inclusions, and matrix comprises nearly half the rock. Many CR chondrites have experienced extensive aqueous alteration, but some have mostly escaped this process.
How are carbonaceous chondrites distinguished?from en.wikipedia.org
There are many groups of carbonaceous chondrites, but most of them are distinguished chemically by enrichments in refractory lithophile elements relative to Si and isotopically by unusually low ratios of 17 O/ 16 O relative to 18 O/ 16 O, when compared to Earth rocks . All groups of carbonaceous chondrites except the CH group are named for a characteristic type specimen:
Why are chondrites considered primitive?from en.wikipedia.org
Because chondrites accumulated from material that formed very early in the history of the solar system, and because chondritic asteroids did not melt, they have very primitive compositions. "Primitive," in this sense, means that the abundances of most chemical elements do not differ greatly from those that are measured by spectroscopic methods in the photosphere of the sun, which in turn should be well-representative of the entire solar system (note: to make such a comparison between a gaseous object like the sun and a rock like a chondrite, scientists choose one rock-forming element, such as silicon, to use as a reference point, and then compare ratios. Thus, the atomic ratio of Mg/Si measured in the sun (1.07) is identical to that measured in CI chondrites ).
Are chondrites valuable?
A common stony meteorite, called a chondrite, can sell for $25 or less, but a slice of iron–nickel pallasite laced with olivine crystals can easily fetch a thousand times that. The stories behind them also matter. A meteorite collected after a witness sees its fall brings gobs of money.
What is the difference between chondrites and Achondrites?
Chondrites are pre-planetary rocks, rocks that formed some 4.5 billion years ago directly from the proto-planetary disk of our Solar Nebula. They represent the first solid materials in our solar system. ... Achondrites on the other hand are pieces of a differentiated planetary bodies, like the Moon or Mars.
Are all meteorites magnetic?
Magnetism: A majority of meteorites are magnetic. If your specimen isn't magnetic, it probably isn't a meteorite. ... Weight Test: Meteorites are much more dense than normal earth rocks. Fusion Crust Test: Fusion crust is a thin, dark rind formed on a meteorite as it streaks through our atmosphere.
What are carbonaceous chondrites rich in?
Meteorites, Comets, and Planets Some carbonaceous chondrites are rich in carbon (CI and CM chondrites have 1.5–6% carbon), but others are not. Carbonaceous chondrites are now defined on the basis of their refractory elemental abundances, which equal or exceed those in CI chondrites.
Where are chondrites found?
Chondrites are the most abundant meteorite class, constituting more than 85 percent of meteorite falls. Like most meteorites, chondrites originated in the asteroid belt where collisions and gravitational perturbations put them into Earth-crossing orbits. (Ordinary chondrites, in particular, are from S-class asteroids.)
What do chondrules look like?
Chondrules are usually about one millimetre in diameter and consist largely of the silicate minerals olivine and pyroxene. From textural and chemical relationships, it is clear that they were formed at high temperatures as dispersed molten droplets, which subsequently solidified and aggregated into chondritic masses.
How do you identify chondrites?
Nickel Iron: Most chondrites contain tiny flecks of nickel iron sprinkled throughout. For this reason, meteorite hunters often use metal detectors in areas where meteorites are likely to be found. A chondrite's high nickel-iron content makes it adhere to a strong magnet.
What Are Chondrules and Chondrites?
Chondrules are rounded objects typically from 0.1 to 5 mm in diameter, with an average size of roughly 0.4mm. They are made primarily of olivine and pyroxene with the occasional bits of glass and other trace minerals.
The Intrigue of the Chondrules
It is because of their early inception that chondrules are important for us to study. By examining their structure and composition we can build models to explain how they formed in the first place. And there lies a big problem: as amazing as it may sound, we really don’t know how they formed.
Problems Everywhere
Now, let’s talk about the problems. And there are plenty of them. For starters, after analyzing their geochemical as well as compositional makeup, it becomes clear that chondrules have multiple reheating events going on.
Solar Nebula Theories
Some scientists who study chondrules subscribe to the solar nebula, from which the solar system originated, as the possible contributor to chondrules. Shock waves from moving objects would create a front passing through the gas and dust, heating up material and giving sufficient pressure to condense material.
Impact Theories
Others instead turn their eye to colliding objects, something else that would have been a frequent event in the early solar system, as the generators of chondrules. Planetesimals would have been frequently colliding with each other, resulting in high speed and high-temperature material being jetted out of the colliding sites.
Jupiter Theories
Some have noted different isotope ratios amongst chondrules, possibly indicating that the supposed uniform formation may not be true.
Radiative Heating Theory
One interesting possibility is that dust clouds near the surface of active planetesimals could get heated as they passed by active lava plumes, condensing into chondrules in the process.
What is the chondrite made of?
Most chondrites contain the anhydrous silicate minerals olivine, orthopyroxene and clinopyroxene, and plagioclase, as well as the nickel-iron minerals kamacite and taenite and the iron sulfide troilite. Some contain claylike hydrous silicates.
What is the most abundant type of chondrite?
Chondrites form the most common type of stony meteorite (the other main type are known as achondrites) and account for roughly 86% of all meteorite falls.
What percent of meteorites are chondrites?
Chondrites are the most abundant meteorites (about 87 percent of stony meteorites) in collections. They also are arguably the most important. In terms of terrestrial rocks, these meteorites seem akin to sedimentary conglomerates—i.e., fragments of preexisting rock cemented together.
Are chondrites valuable?
A common stony meteorite, called a chondrite, can sell for $25 or less, but a slice of iron–nickel pallasite laced with olivine crystals can easily fetch a thousand times that. The stories behind them also matter. A meteorite collected after a witness sees its fall brings gobs of money.
Morphology
There are four recognized Chondrites ichnospecies, however, aberrant forms of unknown taxonomic affinity have been discovered. The fossils are made of infilled dendritic rootlike burrows. The branching angles are 30° to 40°, while a shaft diameter varies between 0.1 mm and 10 mm, remaining constant within a single system.
Interpretation
Though the characteristic burrows are still produced today (in deep-sea deposits), no organism has ever been observed inside them. Several theories exist regarding the origin of these structures.
