Magma Dynamics & Volcanology
Geologists analyze these three primary factors to determine if a volcanic eruption will be violent or relatively quiescent.
What are composition, temperature, and dissolved gas content?
This fundamental concept states that the physical laws governing geology today have remained constant throughout Earth's history.
What is uniformitarianism?
This is the scientific consensus for the current age of the Earth.
What is 4.5(67) billion years?
When a glacier's accumulation exactly equals its ablation, the terminus of the glacier will exhibit this behavior.
What is being stationary?
This is the most abundant gas in Earth's atmosphere
What is nitrogen (N2)?
This magma property increases as the percentage of silica in the melt rises.
What is viscosity?
According to this law, in an undeformed sequence of sedimentary rocks, each bed is older than the one above it.
What is the Law of Superposition?
Occurring at the end of the Paleozoic, this event represents the largest mass extinction in the Phanerozoic.
What is the Permian extinction, also known as the Great Dying?
Between sea ice and glacial ice, this type is typically thinner and originates from freezing ocean water rather than snow.
What is sea ice?
This is the primary wavelength of electromagnetic radiation emitted by the Earth's surface.
What is infrared radiation?
Of all the magma types erupted on Earth, this one is the most abundant.
What is basaltic magma?
This general term describes a buried erosional surface where rock layers are missing from the geologic record.
What is unconformity?
Identified in rocks nearly 3.5 billion years old, these are considered the earliest life forms on Earth.
What are prokaryotes/bacteria?
Variations in Earth's orbit, known by this name, control the pacing of the Quaternary Ice Ages.
What are Milankovitch cycles?
What is the stratosphere?
This is a hazard associated with glaciers on top of active volcanoes.
What are glacial outburst floods (jökulhlaups)?
To be classified as this, an organism must have lived for only a short period of geologic time but be geographically widespread.
What is an index fossil?
Scientists attribute the major source of free oxygen in our atmosphere to this biological group.
What are photosynthesizers?
This controls the direction of groundwater flow.
What is the water table slope?
Roughly this percentage of insolation is absorbed by the Earth's surface?
What is 50 percent?
This type of volcano is the largest on Earth.
What is a shield volcano?
If a rock sample has undergone exactly two half-lives of radioactive decay, this is the percentage of the original parent material remaining.
What is 25 percent?
Some organisms utilize this specific greenhouse gas, for which the modern oceans are a major repository, to construct their shells.
What is CO2 (Carbon Dioxide)?
In a major river system, the gradient (slope) of the channel typically does this as you move downstream.
These two factors have had the most significant effect on atmospheric CO2 concentrations in the last year?
What are greenhouse gas emissions due to human activity and photosynthesis?