A Hawai'ian term for a lava flow with a smooth or ropy surface texture when cooled
What is pahoehoe
A clastic mineral particle smaller than 1/256 mm, or a type of hydrous phyllosilicate mineral
What is clay
This Geologic Era spanned from 541 to 252 million years ago, from the Cambrian radiation to the P/Tr extinction
What is the Paleozoic
Two minerals with the same chemical composition but a different crystal structure
The study of the changes in Earth's life over space and time using rock units and their fossils
What is paleontology
The measure of how readily fluids will flow through a rock
What is permeability
A principle of geology that states that the geologic feature which cuts another is the younger of the two features.
What are cross-cutting relationships
This geologic Period saw the diversification of jawed fish and the invasion of land by multicellular organisms
What is the Silurian
A group of inosilicate minerals, including diopside and augite, which are common in mafic igneous rocks
What is pyroxene
This 'three lobed' arthropod class flourished in the early Paleozoic
What are trilobites
Fine-grained igneous rocks are formed in this manner
What is extrusively
A scientific theory that explains how major landforms are created as a result of Earth's subterranean movements.
What is the theory of plate tectonics
The ocean separating Gondwanaland from Laurasia; the Mediterranean, Black, and Caspian Seas are its remnants
What is the Tethys Sea
This table describes temperatures at which different common silicate minerals change from liquid to solid phase (or solid to liquid).
What is Bowen's Reaction Series
Mound-shaped fossils formed from repeated layering of algal mats covered by trapped sediment
What are stromatolites
This controls crystal size in igneous rocks
What is cooling time
A mass of rock that can be recognized and mapped by its composition, structures, or fossil content
What is facies
The greatest extinction event in Earth's history occurred at the end of this Geologic Period
What is the Permian
This scale is used to identify the hardness of a mineral
What is Moh's hardness scale
These 'sea lilies' were much more abundant in the Paleozoic, sometimes forming thick limestone beds
What are crinoids
A very coarse-grained igneous rock; usually from rapid crystal growth in the final stages of magma crystallization
What is pegmatite
The reworking of soils and sediments by animals or plants.
What is bioturbation
This Geologic Period saw the heyday of Pangaea, vast deserts, and the first true mammals
What is the Triassic
Iron/Magnesium-bearing mica with a vitreous luster and bird's eye extinction under cross-polarized light
What is biotite
A fossil used for dating and correlating the strata in which it's found
What is index fossil