Geology Of the Mantle Flashcards

1
Q

Ultramafic Xenoliths

A

chunks of solid mantle carried upward as inclusions in lava

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2
Q

Chemical reactions and quantum mechanics

A

Ultramafic Xenoliths

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3
Q

Ophiolite

A

a chunk of seafloor that has been pushed up on land, we can detrmine the composition of the mantle by averaging it’s layers

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4
Q

a chunk of seafloor that has been pushed up on land, we can detrmine the composition of the mantle by averaging it’s layers

A

Ophiolite

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5
Q

layers of an ophiolite (bottom to top)

A

Hartzburgite, dunite, gabbro, sheet dikes, pillow bassalts

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6
Q

Hartzburgite, dunite, gabbro, sheet dikes, pillow bassalts

A

layers of an ophiolite (bottom to top)

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7
Q

Lherzolite

A

the forbidden rock we know exists, but can’t see, that makes up the upper mantle. Composed of Olovine, Orthopyroxine, and clinopyroxine

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8
Q

the forbidden rock we know exists, but can’t see, that makes up the upper mantle. Composed of Olovine, Orthopyroxine, and clinopyroxine

A

Lherzolite

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9
Q

Aluminum in the mantle

A

can’t be incorporated int Lherzolite, so insted it forms either plagioclase, spinel, or garnet depending on the conditions

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10
Q

can’t be incorporated int Lherzolite, so insted it forms either plagioclase, spinel, or garnet depending on the conditions

A

Aluminum in the mantle

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11
Q

Olivine collor in hand

A

olive green to greenish grey

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12
Q

olive green to greenish grey

A

Olivine collor in hand

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13
Q

olivine cleavage

A

poor cleavage, in both hand sample and thin section, thin section shows fracturing

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14
Q

poor cleavage, in both hand sample and thin section, thin section shows fracturing

A

olivine cleavage

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15
Q

Olivine habbit

A

either massive or drusty

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16
Q

either massive or drusty

A

Olivine habbit

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17
Q

olivine XPL

A

second order collors like a stained glass window

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18
Q

second order collors like a stained glass window

A

olivine XPL

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19
Q

clinopyroxene in thin section

A

bright 2nd order olors in XPL, has obvious cleavage

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20
Q

bright 2nd order olors in XPL, has obvious cleavage

A

clinopyroxene in thin section

21
Q

Orthopyroxene in thin section

A

1st order colors n XPL with obvious cleavage

22
Q

1st order colors n XPL with obvious cleavage

A

Orthopyroxene in thin section

23
Q

pyroxenes in hand sample

A

nerely impossible to tell orthopyroxine and clinopyroxine appart, forms augite, tends to have hard to see 90 degree cleavage and never has twinning

24
Q

nerely impossible to tell orthopyroxine and clinopyroxine appart, forms augite, tends to have hard to see 90 degree cleavage and never has twinning

A

pyroxenes in hand sample

25
Q

Plagioclase in thin section

A

first order collros with high probability of twinning

26
Q

first order collros with high probability of twinning

A

Plagioclase in thin section

27
Q

plagioclase in hand sample

A

grey to black, twinning is visible in larger crystals, such as in abrodorite, as streaks when held up to light.

28
Q

grey to black, twinning is visible in larger crystals, such as in abrodorite, as streaks when held up to light.

A

plagioclase in hand sample

29
Q

Garnet in thin section

A

constantly extinct in XPL, clear in PPL with high relief

30
Q

constantly extinct in XPL, clear in PPL with high relief

A

Garnet in thin section

31
Q

Garnet in hand

A

has hackley fracture and a distinctive crystal shape, usualy red, but not reliably so

32
Q

has hackley fracture and a distinctive crystal shape, usualy red, but not reliably so

A

Garnet in hand

33
Q

spinel hand sample

A

Magnetite, easily identified by magnetic properties and oxidized metalic luster, tends to grow in oxtahedral shapes

34
Q

Magnetite, easily identified by magnetic properties and oxidized metalic luster, tends to grow in oxtahedral shapes

A

spinel hand sample

35
Q

Pyroxene silicate structure

A

single chains bound together by octahedral groups of the smaller catioic membe (Usualy magnesium) Larger cations glue the layers together

36
Q

single chains bound together by octahedral groups of the smaller catioic membe (Usualy magnesium) Larger cations glue the layers together

A

Pyroxene silicate structure

37
Q

exsolution in thin section (lamelle)

A

fracture lines appear large/bold, because that is where the unwanted stuff is being shoved

38
Q

fracture lines appear large/bold, because that is where the unwanted stuff is being shoved

A

exsolution in thin section (Lamelle)

39
Q

orthopyroxene composition

A

(Mg,Fe) Si2O6, also known as pidgeonite when a little calcium is added in

40
Q

(Mg,Fe) Si2O6, also known as pidgeonite when a little calcium is added in

A

orthopyroxene composition

41
Q

clinopyroxine composition

A

(Mg,Ca) Si2O6, also known as augite, may include some iron

42
Q

(Mg,Ca) Si2O6, also known as augite, may include some iron

A

clinopyroxine composition

43
Q

Lhersolite

A

a dense mixture of clino/.orthopyrocine and olivine that forms under high pressure, the olivine alighns it’s c axis along with the direction of mantle convection

44
Q

a mix of clino/.orthopyrocine mixed with olivine

A

Lhersolite

45
Q

Olivine structure

A

(Mg,Fe)SIO4 Has a TOT structure similar to pyroxene, alhtough it’s an ortosylicate instead of a chain. calcium glues the structures together

46
Q

(Mg,Fe)SIO4 Has a TOT structure similar to pyroxene.alhtough it’s an ortosylicate instead of a chain. calcium glues the structures together

A

Structure of Olivine

47
Q

Structure of Garnet

A

(Ca, Fe, Mg,)3Al2(SiO4)3. has a TOT arrangement

48
Q

(Ca, Fe, Mg,)3Al2(SiO4)3. has a TOT arrangement

A

Structure of Garnet