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rock > igneous rock > differentiated meteorite > differentiated achondrite > asteroidal achondrite > ureilite > low shock ureilite > monomict-poikilitic ureilite > PCA 82506

PCA 82506
subject			fact

PCA 82506	is an instance of monomict-poikilitic ureilite
	is an instance of meteorite find
	has olivine composition Fo% 78
	has pigeonite composition Wo% 6.0 En% 76
	has pyroxene content 0.48 in modal pyroxene/(pryroxene+olivine)
	has reference Goodrich et al. (1987b), Berkley (1986)
monomict-poikilitic ureilite	has olivine inclusions small rounded pyroxene grains (poikilitic)
	has pyroxene inclusions small rounded olivine grains (poikilitic)
meteorite find	has find date when the meteorite was found
	has value lower because the fall was not witnessed
	has weathering can be severe due to long exposure time to environmental corrosion agents
monomict ureilite	has texture large, anhedral olivine and pyroxene grains
	has intergranular boundary curved meeting in triple junctions
	has gain size 1 mm
	has plagioclase 0 %
low shock ureilite	has shock stage S2-S3
	has degree of shock metamorphism low
	has shock pressure less than 20 GPa
	has shock diagnostic mineral no diamonds or lonsdaleite
	has shock diagnostic mineral small euhedral graphite crystals can sometimes be distinguished
	has shock texture silicates show minor fracturing, undulatory extinction and kink bands primarily in olivine
	has olivine shock metamorphism fracturing, undulatory extinction and kink bands
meteorite	has fall date recorded by eyewitness or inferred from dating methods
	has fall location strewn fields, elongated footprints which depends on impact angle, airbursts, and impact velocity
	has fall coordinates in degrees, minutes and seconds of lattitude and longitude
	has fall map which appears as an elongated footprint which depends on impact angle, airbursts, and impact velocity
	can have crater image
	has original mass which can over an order of magnitude greater than total mass of fragment(s) collected at the impact site
	has composition often minerals not found on Earth
	has relative abundance
	has total mass of finds 485755 kg
	has number of finds 1691
	has impact velocity when it hits the ground which is smaller than its velocity before it enters the atmosphere
	has impact angle
	has weather resistance which depends on its composition
	has monetary value large if the fall was witnessed
	has name based on the locale, region, or nearby town in which the fall occurred
	often produce power outages and failures in electrical equipment due to EMP (electromagnetic pulse)
	can be associated with crater
	has origin meteoroid from interplanetary space or fragment dislodged from another planet, moon or planetesimal
	vaporizes completely if size is between 3 micrometers and 3 millimeters
	can survive fall if size is larger than 3 mm and velocity is less than 24 km per second
	can survive fall if it fragments because smaller pieces with less mass are more easily slowed by the atmosphere
	has ablative mass loss depending on composition, more friable stony meteoroids loses more mass than iron meteoroid
	has ablative mass loss directly proportional to initial velocity
	can shatter during impact phase
	can fragment during meteor phase
	has fragmentation probability during meteor phase which depends on composition
ureilite	has letter designation AURE
	has characteristic mineral olivine-pigeonite about 90% by volume
	has matrix composition carbon, metal, sulfides small silicate grains along grain boundaries less than 10% by volume
	has minerology olivine, pyroxene (some combination of pigeonite, orthopyroxene, augite)
	has petrology coarse-grained granular
	has likely origin partial melting residue
	has olivine grain characteristic reduced rims contacting carbonaceous matrix material 0.1 mm FeO-free olivine and/or enstatite rims riddled with tiny inclusions of low-Ni metal
rock	has part mineral
	has genesis
shocked meteorite	has metamorphism mechanism shock metamorphism
plutonic rock	has solidification mechanism cooling in deep underground chambers
	has solidification timescale very slow
achondrite	has distinguishing feature no chondrules

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