EM1 - Principles of Geology [Midterm Reviewer]

Conchoidal

surfaces are somewhat rounded, shell-like (quartz)

Sills

resemble buried lava flows and may exhibit columnar joints

Structural geology

deals with the position of rock bodies and with tectonic geology interprets the forces causing them to be deformed or broken.

Geochronology

is a system of dating developed, for the purposes of study of the earth's history.

Paleogeography

the geography of the geologic past; concerns all physical aspects of an area that can be determined from the study of rocks.

CRYSTALS

geometric forms of minerals produced by repeating pattern of atoms that is present throughout the mineral

A mineral is

Naturally occurring, Definite chemical composition, Inorganic solid, Crystalline structure, Definite set of chemical and physical properties

Native Minerals

composed of single elements

Color

least useful; change in chemical formula will vary the color of the mineral

Luster

appearance of mineral in reflected light

Vitreous

shiny; glass

Resinous

resin

Pearly

pearl (ex. opal)

Waxy

dull shine like wax

Earthy

no shine

Greasy

it looks as if covered with a thin layer of oil.

Silky

it looks like the appearance of silk.

Streak

color of a mineral's powder

Cleavage

tendency of a mineral to break/separate along planes of weaknesses. (has a pattern/weakness part)

Fracture

the manner in which a mineral breaks in any direction

Uneven

rough surfaces, no distinguishable pattern

Hardness

the resistance offered by the smooth surface of a mineral to abrasion or scratching

Effervescence

adding HCL to a mineral causes it to fizz

Magnetism/Magnetic

ability to attract a magnet

Double Refraction

splits light rays (Calcite)

Fluorescence

the ability to glow under ultraviolet light (sphalerite)

Tenacity

the property of minerals that can resist crushing, bending, or tearing or in short, its cohesiveness.

Geologic Time scale

a system used by scientists to describe the timing and relationships between events in Earth's history. It covers a vast expanse of time, from the formation of the planet nearly 4.6 billion years ago to the present day.

EONS

largest division of the geologic time scale; spans hundreds to thousands of million of years ago; based on the abundance of certain fossils

ERA

division in an Era that span time periods of tens to hundreds of millions of years; marked by major changes in the fossil record

PERIOD

a division of geologic history that spans no more than one hundred million years; Based on types of life existing at the time

EPOCH

is a subdivision of the geologic timescale that is longer than an age and shorter than a period; the smallest division of the geologic time scale characterized by distinctive organisms

CATASTROPHISM

the generally accepted idea of how the Earth was formed

UNCONFORMITIES

Geologic time is continuous; it has no gaps. In any sequence of rocks, however, there are many major discontinuities (unconformities) that indicate significant interruptions in the rock-forming processes.

RELATIVE DATING

simply determining the chronologic order of a sequence of events.

Principle of superposition

states that in a sequence of undeformed sedimentary rock, the oldest beds are on the bottom and the higher layers are successively younger.

Principle of horizontality

All rock layers were originally deposited horizontally.

Principle of original lateral continuity

Originally deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer.

Principle of cross cutting relationships

States that igneous intrusions and faults are younger than the rocks they cut.

Jurassic

was first introduced for strata outcropping in the Jura Mountains.

Quaternary

the name proposed for very recent deposits, which contain fossils of species with living representatives.

Lord Rutherford

he made the first clear suggestion that radioactive decay could he used to date geologic events in absolute time.

Sedimentary rock

is formed from the weathered products of preexisting rocks that have been transported, deposited, compacted, and cemented.

Metamorphic rock

formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

Nonfoliated Metamorphic Rock

Does not have a banded texture

Volcanism

process by which magma from the interior of the earth rises through the crust, emerges onto the surface as lava, and cools into volcanic rock

Pyroclastic materials

the name given to particles produced in volcanic eruptions.

Pumice

frothy, air-filled lava

Lapilli

walnut-sized particles

Conduit

carries gas-rich magma to the surface.

VOLCANIC DOMES

Explosive eruptions consisting of felsic volcanism, High silica and high viscosity, ash flows

Geology

study of the earth

Physical Geology

deals with the materials that constitute the earth, the structure and surface features and the processes that have given the earth its present appearance.

Historical Geology

Deals with the forces and processes which operate on/upon the surface and within the interior of the earth which brings about changes and reduces the earth's features as we see today.

Mineralogy

study of minerals

Oceanography

study of oceans and their basins

Paleontology

study of fossils

Petrology

study of rocks

Stratigraphy

is the study of the layered rock chiefly those of sedimentary in origin.

Geodesy

is concerned in the measuring of the form and size of the earth.

Geomorphology

is the study of landforms, their origin and developments.

Geophysics

deals with the application of the principles of physics to the study of the earth.

Geochemistry

is the study that deals with the application of the principles of chemistry to geology.

Seismology

is the study of earthquakes.

Volcanology

is the study of volcanoes

Hydrology

is the study of surface & subsurface waters.

Sedimentology

the science concerned with the description, classification, origin and interpretation of sediments & sedimentary rocks.

Planetology/ planetary geology

a science that applies geologic principles and techniques to the study of planets & their natural satellites.

Paleoecology

the study of the interrelationship between organisms & their environment of the geologic past.

Environmental geology

application of geologic information to environmental problems.

Hypothesis

an idea concerning an event and its possible explanation ; an assumption

Theory

Explanation; this has been proven already

NEBULAR HYPOTHESIS

this explains that the matter that made up the planets, satellites and the sun was a huge spheroidal nebula (gaseous matter) which had acquired rotational motion, though slow at first, gradually became faster & faster due to gravitational contraction and because of centrifugal force some portion escape outward thereby forming the planets, satellites & other heavenly bodies.

PLANETESIMAL HYPOTHESIS

it explains that the sun traveled alone until it almost collided with another star. In that encounter, tidal stresses generated by the pull of the passing star partly disrupted the sun and set the fragments on the plane around it. This debris was then slowly gathered to form the planets and their satellites, and the residue being left in the form of planetoids & meteors but were caught in the gravitational field of the planets.

TIDAL HYPOTHESIS

This explained the origin of the solar system as a result of a close encounter between the Sun and a second star. However, it differed significantly from the other major catastrophic hypothesis of the 20th century, the Chamberlin-Moulton planetesimal hypothesis.

DUST CLOUD HYPOTHESIS

The interplanetary dust cloud is cosmic dust (small particles floating in space) which pervade the space between planets in the Solar System and in other planetary systems. It has been studied for many years in order to understand its nature, origin, and relationship to larger bodies.

NOVA HYPOTHESIS

A nova is a cataclysmic nuclear explosion triggered by hydrogen accretion on a white dwarf star's surface, igniting nuclear fusion in a runaway manner.

BIGBANG THEORY

According to this model, the Universe expanded from an extremely dense and hot state and continues to expand today.

Crust

composed of rocks & minerals

Mantle

composed of rocks so hot where they are partly melted

Outer Core

composed of the liquid metal

Mohorovicic discontinuity

means zone of change

Primates

any of the highest mammals including man.

MINERALS

Made up of single elements or compound

ELEMENTS

substance that cant be broken down to any simpler substance

Silicates

any mineral which is a silicate must contain Si (Silicon) and O (Oxygen) in their chemical formula

PHYSICAL PROPERTIES

Reflection of the internal arrangement of their atoms

Adamantine

brilliant glow; diamond

Fibrous

jagged surface like fibers (Wollastonite)

UNIFORMITARIANISM

It assumes that the chemical and physical laws operating today have operated throughout all time.

Principle of faunal succession

states that groups of fossil animals and plants occur in the geologic record in a definite and determinable order and that a period of geologic time can be recognized by its characteristic fossils..

Inclusion principle

States that a fragment of a rock incorporated or included in another is older than the host rock

PRECAMBRIAN

represented by a group of highly complex metamorphic and igneous rocks, which form a large volume of the continental crust.

Paleozoic

"ancient life;"

Cambrian

comes from Cambria, the Latin name for Wales, where these rocks were first studied.

Ordovician

is derived from the name of an ancient Welsh tribe

Silurian

designates rocks are exposed on the border of Wales, a territory originally inhabited by a British tribe

Devonian

was first used to refer to rocks exposed in Devonshire, England.

Carboniferous

the name of a sequence of coal-bearing formations that lie above the Devonian rocks.

Silurian

designates rocks are exposed on the border of Wales, a territory originally inhabited by a British tribe,