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1
Q

Dip

A

Angle at which the plane is inclined from the horizontal
Calculate tanD= v(contour height)/h(distance between contours)

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2
Q

Dip direction

A

Direction in which the structure contour lines decrease in topographical height

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3
Q

Outlier

A

Younger rock surrounded by older
Mainly in ridges

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4
Q

Inlier

A

Older rock surrounded by younger
Mainly in valleys

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5
Q

What is a syncline fold?

A

When younger rocks are in the middle

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6
Q

What is an anticline fold?

A

When the older rocks are in the middle

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7
Q

Ecology, Taphonomy and Time scale of Stromatolites

A

Microbial mats
Deposition around and got preserved
Pre-cambrian to present

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8
Q

Ecology, Classification and Time scale of Trilobites

A

Burrowing, scavenger feeders
Moulting behaviour
Rapid burial perhaps
Phylum: Arthropoda
Cambrian- end Permian (251.9Ma)

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9
Q

Ecology, Classification and Time scale of Graptolites

A

Filter feeders, colonial
Phylum: Hemichordata
mid Cambrian (520Ma)- mid Carboniferous (320Ma)

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10
Q

Ecology, Classification and Time scale of Bivalves

A

Burrow (mya), Swimmers (Pecten), Cementers (Ostrea)
Benthic and epifaunal/infaunal
Phylum: Mollusca
Cambrian to present

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11
Q

Ecology, Classification and Time scale of Brachiopods

A

Filter feeders, pedicle attaches, toothed hinges (rarely found open)
Mollusca Brachiopoda
Cambrian to present

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12
Q

Ecology, Classification and Time scale of Echinoids

A

Filter feeder/ grazer dorsal at the top ventral underneath with teeth
Pentaradial symmetry
Phylum: Echinodermata
Cambrian to present

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13
Q

Ecology, Classification and Time scale of Crinoids

A

Suspension feeders, attach to logs and float
Ossicles often preserved
Phylum: Echinodermata, Class: Crinoidea
mid Cambrian to present

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14
Q

Ecology, Classification and Time scale of plants

A

Autotrophic, photosynthesise, respire, sessile
e.g. Genus Stigmaria, from Plantae kingdom
Cambrian to present

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15
Q

Ecology, Classification and Time scale of Bryozoan

A

Colonial, filter feeders, provide shelter
Phylum: Bryozoa, class of Gymnolaemata most successful
Ordovician (485Ma)

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16
Q

Ecology, Classification, Preservation and Time scale of ammonoids

A

Free swimmers, carnivorous
Aragonite shell, and moulds
Phylum: Mollusca, Class: Cephalopoda, Orders: Goniatitic, Ceratitic, Ammonitic
G=Dev (420-360Ma) -Permian (300Ma-251.9Ma)
C= Triassic (251.9Ma-200Ma)
A=Triassic- Cretaceous (66Ma)

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17
Q

Ecology, Classification, Preservation and Time scale of Nautiloids

A

Jet propulsion, Carnivores
Aragonite shell
Phylum: Mollusca, Class: Cephalopoda, Subclass: Nautiloid
Cambrian, then Triassic (251.9Ma-200Ma) coiled only

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18
Q

Ecology, Classification and Time scale of corals

A

Solitary/ Colonial
Phylum: Cnidaria, Subclasses: Scleractinia, Rugosa, Tabulata
T+ R= Ordovician (485Ma)- Permian (251.9Ma), in calcite
S= Triassic (250Ma) - present, in aragonite

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19
Q

Ecology, Classification, Presevation and Time scale of belemnites

A

Mesozoic squid, swimmers, carnivorous
Phylum: Mollusca, Class: Cephalopoda, Order: Belemnitida
Calcite guard
Jurassic (200Ma-145Ma) - Cretaceous (145Ma-66Ma)

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20
Q

How does a schist differ to a gneiss in thin section?

A

Schist- tiny crystals barely visible in clear lineation, muscovite, biotite
Gneiss- larger quartz crystals present, banding when looking with naked eye, quartz, feldspar

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21
Q

What are the optical differences between Clinopyroxene and Orthopyroxene?

A

Clinopyroxene- Inclined extinction, Colourless/ greyish, Pink to orange with CP
Orthopyroxene- Straight extinction, Colourless/ reddish/ green, Grey to purple with CP

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22
Q

Describe the optical properties of magnetite

A

Black in Plane and cross polars
Small
Can be found as intrusion

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23
Q

What are the optical properties of Olivine?

A

Curving cracks
Bright second order colours CP
Pale yellow PP
High relief
Quite euhedral usually

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24
Q

What are the optical properties of plagioclase feldspar?

A

Lamellar twinning CP
Low relief
Distinct cleavage
Inclined extinction

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25
What are the optical properties of Amphibole/ Hornblende?
Pleochroic green to brown Clear cleavage 56 and 124 degrees Shows twinning High second order interference
26
What are the optical properties of quartz?
Low relief No cleavage Low 1st order colours
27
What are the optical properties of garnet?
Colourless Isotropic High relief
28
What are the optical properties of biotite/ mica?
Speckled extinction Straight extinction May contain zircons Low relief Pleochroic
29
What are the optical properties of orthoclase/ K+ feldspar?
Straw colour Lack of striations Low birefringence Pleochroic Cleavage No barcode extinction
30
What are the optical properties of microcline feldspar?
Cross hatch extinction Low relief Colourless Inclined extinction
31
What are the optical properties of muscovite/ mica?
Rainbow coloured CP Moulted appearance Green tint in PP Straight speckled extinction
32
What are the optical properties of chlorite?
Some pleochroism Some twinning Green tint PP Brown/ Dark green/ blue CP (not on chart)
33
What are the optical properties of epidote?
Yellow- green pleochroic High relief purple w/orange outline in CP Some lamellar twinning Inclined extinction
34
What does a red colour in a rock suggest? What type of magma/ minerals are likely to be present?
Red suggests oxidised iron Minerals: Quartz, feldspar Magma: Rhyolitic
35
What are the 3 low density igneous rocks and their differences?
Pumice- light coloured Scoria- dark coloured Tuff- orange, brown, more sediment like
36
What are the features of a QFP and Quartz porphyry?
Large crystals of quartz and feldspar, in a fine ground mass May have some iron staining Rhyolitic magma origins, high Si content
37
What are the features of a breccia?
Large angular clasts In a fine ground matrix Large variety of minerals Poorly sorted
38
What are the features of eclogite and its original environment?
Green - pyroxene Pink- garnet Basaltic origins, undergone metamorphism Some quartz, amphibole
39
What are the features of amphibolite and its origins?
Black- hornblende, slightly shiny White- K+ feldspar Regional metamorphism, from basaltic origins
40
What are the features of quartzites?
Sandpaper glassy texture Pink and white crystals (Q and K feldspar)
41
What are the features of pelites and its origin?
Fine grained Dark coloured Originally mudstone/ siltstone
42
What are the features in ooids and their origins?
Small spherical spheres Dark brown radial rings Made of calcite Formed in shallow tropical waters
43
What are the features of conglomerates and their origins?
Rounded clasts in a fine grained matrix From floods Matrix may be sand (quartz)
44
What are the properties of a limestone and its origin?
Easily scratched Light coloured Reasonably small grain size Formed from precipitation out of water due to biological and non-biological processes
45
What are the properties and origin of chalk?
Low density White Formed from remain of marine organisms
46
What are the properties and origins of dolomite?
Slight red colour Ca:Mg 1:1 May have cavities due to alteration shrinkage Formed in high intertidal and sabkhas (coastal mudflat)
47
What are the properties and origins of chert/ flint?
Conchoidal fracture Dark brown/ grey colour Non-clastic formed from microcrystalline quartz Form as nodules
48
Give a technical description of a brachiopod
- Contains a pedicle which it uses to attach - filter feeder - Pedicle is at the posterior end - Diductor muscles for opening - Adductor muscles for closing - Leaves less muscle scars and has less muscle mass - Has tooth and socket system
49
Give a technical description of a bivalve
-Only has adductor muscles - Open when adductor muscles relax - Beak is called the umbo, and points towards anterior - Has pallial line inside- marks where muscles attached - Very clear muscle scars - Contain ligament near tooth - Has tooth and socket system
50
Why does calcium carbonate sometimes biomineralize in calcite and sometimes aragonite?
Depends on the minerals present in the water If no Mg present then will biomineralize in stable calcite, if Mg present will form metastable aragonite
51
Original composition of skeletal material of trilobites
Calcium carbonate- specifically calcite
52
Original composition of skeletal material of echinoids
Calcium carbonate- specifically calcite Ossicles formed of small calcite crystals
53
Original composition of the skeletal material of bivalves
Calcium carbonate
54
How do muscovite and biotite differ?
Hand specimen Biotite- black, dark Muscovite- light, w/green tinge PP Biotite- Brown/ green Muscovite- colourless CP Both show straight speckled extinction
55
What are the optical properties of augite?
Clear cleavage, many parallel to each other Second order blue, orange CP Pale colourless in PP Moderate relief Clinopyroxene so inclined extinction
56
What are examples of black minerals in hand specimen?
Magnetite Biotite mica Augite pyroxene (dark green) Hornblende/Amphibole
57
What are the properties of Diorite?
White- plagioclase Black- biotite Present are also pyroxene and amphibole Intrusive rock (large crystals), acidic origins
58
What are the properties of gabbro?
Coarse grained intrusive mafic rock Dark minerals- Pyroxene Lighter minerals- feldpspars
59
What are the properties and the environment formation of blueschists ?
Blue colour Blue- glaucophane Green- epidote, jadeite Pink- garnet Metamorphism at subduction plate Originally basaltic (oceanic plates)
60
What are the properties and environments of formation for marble?
White, pink Granular texture Metamorphosed limestone
61
What are the differences between nautiloids and ammonoids?
Nautiloids thicker shell Nautiloids simpler suture lines Ammonoids septa curve inwards into body Nautiloid siphuncle central, ammonoid is lateral
62
How can tectonic setting be inferred from thin sections?
Large crystals- intrusive vice versa Quartz- rhyolitic magma, olivine/ pyroxene- basalt Presence of muscovite, chlorite, glaucophane, epidote- suggest metamorphism
63
What are the optical properties of glaucophane?
Blue Good cleavage Twinning Accompanied with epidote and jadeite
64
What are the optical properties of spinel?
Isotropic No cleavage High relief Brown in PPL In mafic igneous rocks
65
What are the optical properties of serpentine?
Green in PPL Low relief 1st order birefringence 'skin of a serpent'
66
What part of a belemnite is commonly preserved?
(Rostrum) Calcitic guard
67
What are the key features on an echinoid?
Periproct (anus) Peristome (mouth) ambulacra (where spines attach 5 radial things) Interambulacra (inbetween the above) Spine attachement Ventral and dorsal
68
How to calculate stratigraphic thickness?
Cos(Dip) x vertical thickness (calculate by the contour structure difference between top and bottom of boundary)
69
How to estimate dip direction?
If valley, then direction of veeing If ridge then opposite direction to veeing
70
What 4 labels should be added to graptolites?
Nema Sicula Thecae Stipe

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