GEOL: Midterm 2

Approximately how long ago did the first multicellular organisms appear on Earth? (hint: think about the life explosion around 540 Ma)

600 million years ago

______ consists of shells.

Biochemical sedimentary rock

Coral reef is one kind of _________.

Biochemical sedimentary rock.

Beginning with the Cambrian Period, life on Earth left a clear record of evolution. The fossil record indicates that soon after the Cambrian began, life underwent remarkable diversification. This event, which paleontologists refer to as the _______.

Cambrian explosion.

______ is made up of minerals that precipitate directly from water solutions.

Chemical sedimentary rock

As a result of the impact of a 10-km-wide meteorite at the present of Yucatan Peninsula in Mexico, where a 100-km-wide by 16-km-deep scar called the ________ crater was created, then the Cretaceous Period came to a close and _______ disappeared.

Chicxulub, dinosaurs

______ is the process by which sediment settles out of the transporting material.

Deposition

We know that Tiktaalik, the first fish, could walk on land at the end of Devonian period. Which geological period is known as the "Age of Fishes" due to the abundant diversity of fish species during that time?

Devonian Period

A'a' flows have smooth, ropy surfaces, whereas Pahoehoe flows have rough, rubbly surfaces. True or False?

False

Gneiss is a kind of sandstone that formed by the lithification of fossils. True or False?

False

Metamorphic rock is one that forms when a preexisting rock, or protolith, undergoes a fluid-state change in response to the modification of its environment. True or False?

False

Quartzite is one kind of sandstone. True or False?

False

Rhyolitic lavas can flow great distance. True or False?

False

Sediments generally accumulate in continuous sheets, which is called the principle of horizontality. True or False?

False

The class of foliated metamorphic rocks includes shale, slate, phyllite, metaconglomerate, schist, and gneiss. True or False?

False

Aquitard can transmit water easily. True or False?

False.

Which ancient group of organisms were the dominant forms of life during the Paleozoic Era and included species like trilobites and brachiopods? (hint: trilobites and brachiopod)

Invertebrates

Which era is known as the "Age of Dinosaurs"?

Mesozoic Era

__________ provides the age of a geologic feature in years.

Numerical age

________ consists of carbon-rich relicts of plants.

Organic sedimentary rock

Which ancient supercontinent is believed to have existed around 335 million years ago and eventually broke apart to form the current continents? (hint: Rodinia to Pinnotia to Gondwana then ...)

Pangea

_________ is a measure of the ease with which fluids can flow through a porous material.

Permeability

________ refers to the total volume of empty space in a material, usually expressed as a percentage.

Porosity

______ specifies whether one geologic feature is older or younger than another.

Relative age

Successive collision ultimately brought together most continental crust on Earth into a single and the first supercontinent, name ________, by around 1 Ga. [hint: the oldest continent]

Rodinia

______ broadly defined, consists of loose fragments of rocks or minerals broken off bedrock, mineral crystals that precipitate directly out of water, and shells or shell fragments.

Sediment

_________ of class indicates the degree to which the class in a rock are all the same sizes or include a variety of sizes.

Sorting

A volcano's shape depends on the type of eruption. True or False?

True

An igneous intrusion bakes surrounding rocks. The rock that has been baked must be older than the intrusion, which is called the principle of baked contracts. True or False?

True

Changing temperature and pressure are the two important factors causing the metamorphism. True or False?

True

Effusive eruptions (i.e., basaltic eruption) produce only flows of lava, whereas explosive eruptions (i.e., rhyolitic eruption) produce cloud a flow of pyroclastic debris. True or False?

True

Radical climate shifts occurred on Earth at the end of the Proterozoic Eon. Specially, accumulations of glacial sediments occur worldwide indicating the whole Earth's surface was covered by ice twice in the history of the Earth. True or False?

True

Rocks below an angular unconformity are usually tilted or folded before the unconformity developed. True or False?

True

Slate is a kind of metamorphic rock derived from the metamorphism of shale. True or False?

True

Trilobites used to be living and grazing the sea floor during the Paleozoic Era. True or False?

True

The river stream channel cross-sectional shape resemble the letter ______, this landform is called a ______.

V, V-shaped valley.

_______ are vents at which molten rock (lava), pyroclastic debris, gas and aerosols erupt at the Earth's surface.

Volcanoes

Much of the transformation of the Earth's atmosphere from the oxygen-poor volcanic gas mix of the Archean Eon to an oxygen-rich mix had occurred by about 1.8 Ga. This transition led to the global deposition of _________.

banded iron formation (BIF).

Fluvial deposits may accumulate along the stream bed in elongate mounds called _______.

bars.

If a stream divides into numerous strands weaving back and forth between elongate mounds or bars of gravel and sand, the result is a _______ stream.

braided

The summit of an erupting volcano may collapse to form a bowl-shaped depression called a ________.

caldera

Clastic rocks form from ________ grains.

cemented-together

Piles of tephra form a cone-shaped _________.

cinder cone.

Technically speaking, we define _______ as the volume of water passing through an imaginary cross section of the stream in a unit of time.

discharge

Geologists refer to volcanoes that have not erupted for hundreds to thousands of years but do have the potential to erupt again in the future as _________.

dormant volcanoes.

A drainage network collects water from a broad region, variously called a _________, catchment or watershed.

drainage basin

The highland, or ridge, that separate one watershed from another is a _______.

drainage divide.

Permanent streams flow all year long, whereas ______ streams flow only part of the year.

ephemeral

When the volume of water flowing in a stream exceeds the volume of the channel, a _____ occurs.

flood

A stream may overtop the banks of its channel and spread out over its ________.

floodplain.

Preferred mineral orientation in a piece of metamorphic rock is _______.

foliation.

There are ______ major classes of sedimentary rocks.

four

The water that resides under the surface of the Earth is called _______.

groundwater.

Physicists can measure how long it takes for half of a group of parent isotopes to decay. This time is called ______.

half life

The potential energy available to drive the flow of a volume of groundwater at a given location is called the ________.

hydraulic head.

Some life species existed only for a short interval of the geologic column, and thus are diagnostic of a particular period or epoch. The fossil of such species are called _______.

index fossil.

Very wet mixtures of volcanic ash, coarser debris, and water during a volcano eruption form a slurry known as a _____.

lahar.

Pea-to-plum-sized fragments of glassy lava and scoria from basaltic eruption are called cinders, or ________.

lapilli.

The metamorphism of _____ yields marble.

limestone

The transformation of loose sediment into solid rock is _________.

lithification.

For part of the early 600 million years of Earth history, the Hadean Eon, the planet was so hot that its surface was a _____ ocean.

magma

River cannot sail in a straight line, for the river channel winds back and forth in a series of snake-like curves called ______.

meanders.

Changes in a rock that result in the formation of a metamorphic mineral assemblage, and/or metamorphic foliation, in response to a change in temperature, and/or pressure, to the application of differential stress, and to interaction with hydrothermal fluids are called ___________.

metamorphism.

Radioactive isotopes in the rocks are unstable; after a given time, they undergo a change called _________.

radioactive decay.

During the metamorphism, changes in shape and size of grains without changing the identity of the mineral constituting the grains are called ______.

recrystallization.

Geologists refer to the total volume of sediment carried by a stream as its _______.

sediment load.

Some water flows downslope as a thin film called _______.

sheetwash.

Unconsolidated deposits of volcano pyroclastic grains, regardless of size, constitute ________.

tephra.

As the main channel lengthens, new side channels form nearby. These side channels or _______ always merge with the main channel trunk.

tributaries

A surface representing a period of non deposition and possibly erosion is called _____.

unconformity.

Physical processes we observe today also operated in the past at roughly the same rates and were responsible for the formation of the geologic features we see in outcrops. This principle is called _______.

uniformitarianism.

The characteristics of a lava flow depend on its ______, which in turn depends on its temperature and composition.

viscosity

Above ______, the pore spaces in the sediments or rocks contain mostly fire and below which they contain only water.

water table