Geology Exam 1 Study Guide (we can do it baddies)

Crystal

Crystal

solid material with a definite repeating pattern, occurring in a specific order

Mineral

a naturally occurring, inorganic, crystalline solid with a narrowly defined chemical composition and characteristic physical properties

Cubic Crystal

Tetragonal Crystal

Triclinic Crystal

house-shaped crystal

Monoclinic Crystal

hexagonal crystal

Orthorhombic crystal

Color

Physical property — color of the mineral

Streak

Physical property — color of a fine powder from the mineral

Hardness

Physical property — how resistant the mineral is to scratching

Luster

Physical Property — How light reflects from the mineral surface

Cleavage

Physical Property — breaking of the mineral along lines of crystallographic weakness; may be zero or multiple directions

Fracture

Physical Property — How the mineral breaks, not due to crystal structure; conchoidal is common

Specific Gravity / Density

Physical Property — a measure of the mass of mineral per unit volume (space it takes up)

Crystal Form

Physical Property — the ideal shape of the mineral from the arrangement of atoms in the crystal lattice structure

Crystal Habit

Physical Property — A distinctive shape from growth of the mineral

Magnetism

Physical Property — Being Magnetic

Acid Reaction

Physical Property — When dilute hydrochloric acid is placed on a mineral containing carbonate, a reaction occurs where CO2 is produced

Taste

Physical Property — halite is salty, sylvite is bitter, clay minerals stick to your tongue

Odor

Physical Property — What the mineral smells like

Feel

Physical Property — How the mineral feels (soapy, greasy, rough)

Facets

How a crystal WANTS to break

Crystal Lattice

a definite, repeating pattern in crystals

Felsic

silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium

Mafic

igneous rock or magma that is relatively high in magnesium and iron content

Igneous/Magmatic Rocks

Rocks formed from crystalized/solidified magma (molten rock)

Sedimentary Rocks

 rocks formed from bits and pieces of sediment

Metamorphic Rocks

rocks produced from other rocks, generally beneath earth’s surface, by heat, pressure, and chemically active fluids

Silicates

Minerals that have Oxygen and Silicon, most common on earth

Siliciclastic sedimentary rocks

cemented quartz grains with varying grain size.

Chemical sedimentary rocks

formed by (bio)chemical precipitation carbonates, evaporites, iron-rich, phosphates. 

Biochemical sedimentary rocks

formed from organic processes 

Volcanic Sedimentary rocks

sedimentary rock UNDER igneous rocks

Non-foliated Metamorphic rocks

rocks that have no layers

Foliated metamorphic rocks

planar arrangement of layers within a metamorphic rock

Fossil

any preserved remains, impressions, or traces of a living organism from the geological past

Fossilization

when after death, the organism’s tissues are replaced by minerals

Trace fossilization

disturbed sediments preserved through diagenesis

Permineralization

Permeate the pore space and crystallize. Occur in porous tissue such as bone and wood.

Recrystallization

involves a change in crystal structure, NOT chemical

Replacement

substitution of original skeletal material

Carbonization

the organism is preserved as a residual, thin film of carbon

Molds/casts

the organism leaves an imprint in the sediment

Index fossil

allow geologists to correlate sedimentary strata from different locations

Importance of the Ediacaran Biota

represents the earliest known assemblage of complex multicellular organisms

Cyanobacteria

 caused the Great Oxidation

Trilobites

filter-feeders

Sponges

Single-organism

Cnidaria

Major reef-builders

Ostracods

easily fossilized

Brachiopods

peaked in the Paleozoic

Bryozoan

often resemble coral

Crinoids (Echinodermata)

sessile filter-feeders

Conodonts

lived for around 300 million years

Graptolites

colonial filter feeders

Cephalopods (Orthoceras)

long, straight shell

(Gastropods and Bivalves)

appeared in Ordovician

Armored Fish

appeared in Devonian

Shark

appeared in early Jurassic

Precambrian era

 Hadean, Archean, Proterozoic

Paleozoic era

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian

Mesozoic era

Triassic, Jurassic, Cretaceous

Unconformity

a break in time in an otherwise continuous rock record

silicate structure

4 oxygen atoms surrounding a silica atom

Nesosilicates

simplest silicates; single tetrahedrons like the picture above; ex. Olivine, garnet, zircon.

Sorosilicates

two tetrahedrons joined at a single corner (each tetrahedron sharing 1 oxygen); ex. Epidote and allanite.

Cyclosilicates

tetrahedrons sharing 2 oxygen corners each, forming rings; ex. Beryl and tourmaline.

Inosilicates

double/interlocking “chained” lines of tetrahedrons; ex. Pyroxene and amphibole.

Phyllosilicates

continuous sheets of tetrahedrons, each sharing all three corners; ex. Kaolinite, talc, muscovite, and biotite.

Tectosilicates

three-dimensional interlocking of tetrahedrons, where all 4 points are sharing oxygens with other tetrahedrons; ex. Quartz and orthoclase.