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rock > meteorite > achondrite > primitive achondrite

primitive achondrite
subject			fact

primitive achondrite	is a kind of achondrite
	is a kind of undifferentiated meteorite
	has minerology olivine, orthopyroxene, clinopyroxene, metal with some troilite and some sodic plagioclase
	has petrology fine- to coarse-grained equigranular
	has likely origin ultrametamorphism, partial melting with some melt migration
achondrite	has relative abundance 7.1 % of meteorite falls
	has distinguishing feature no chondrules
	has number of finds 70
	has total mass of finds 1606 kg
undifferentiated meteorite	has peak temperature less than 950 degree Celsius during its entire history since solidification
	has parent body asteroid smaller than 100 km in diameter
	has age oldest and most primitive rock in solar system
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 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
stony meteorite	has weather resistance low
	has fragmentation probability high because it is more friable than iron meteorite
	has ablative mass loss high because it is more friable than iron meteorite
conglomerate	has sediment mechanism agglomeration of particles, many of which record individual, diverse histories
rock	has part mineral
	has texture
	has genesis

Kinds of primitive achondrite :

• acapulcoite (4 kinds, 4 facts)
• lodranite (4 kinds, 5 facts)
• ungrouped primitive achondrite (1 kind)
• winonaite (5 kinds, 4 facts)

Next achondrite: differentiated achondrite    Up: achondrite, undifferentiated meteorite