on a date
This cosmogenic isotope is useful for dating organic matter.
What is Carbon-14?
This letter describes the shape characteristic of glacial valleys.
What is U?
This texture develops in metamorphic rocks when platy minerals align perpendicular to the direction of maximum compressive stress.
What is foliation?
The smallest repeating block that builds up a crystal lattice.
What is a unit cell?
The most common type of meteorite.
What is chondrite?
This geological period of the Neoproterozoic Era was formally ratified in 2004 as the first new geological period established in over a century.
What is the Ediacaran?
The five-part vertical sequence of sedimentary structures deposited by a turbidity current.
What is the Bouma sequence?
On a binary phase diagram, this invariant point represents the temperature and composition where the maximum number of phases can coexist in equilibrium.
What is the eutectic point?
This point group contains one 3-fold rotational axis perpendicular to a mirror plane.
What is 3/m?
The Lunar highlands primarily consist of this rock.
What is anorthosite?
The correction factor accounting for the partitioning of heavy and light isotopes between two phases at equilibrium.
What is the fractionation factor?
This form of cross-bedding occurs in tidal environments where the water flows in one direction during flood tide and the opposite direction during ebb tide.
What is herringbone cross-stratification?
This term describes a trace element that strongly prefers the melt phase over the solid crystalline phase.
What is an incompatible element?
These crystal systems have two optic axes and three unequal principal indices of refraction.
What are orthorhombic, monoclinic, and triclinic?
These are the only three features on Venus not named after real or mythological women.
What are Alpha Regio, Beta Regio, and Maxwell Montes?
The Great Oxidation Event began and ended in these two periods of the Paleoproterozoic era.
What are the Siderian and Rhyacian periods?
These cyclically laminated layers of sedimentary rock exhibit varying thickness and grain size reflecting periodic tides.
What are tidal rhythmites?
Because they partition heavily into garnet, the depletion of these specific elements in a primitive basalt indicate that the melt originated deep within the garnet-peridotite stability zone.
What are Ytterbium and Lutetium?
The dodecahedral (X) site in garnet group minerals is typically occupied by these specific divalent cations.
What are Ca2+, Fe2+, Mg2+, and Mn2+?
Martian valley networks exhibiting ampitheatre-like channels are attributed to this erosional process.
What is groundwater sapping?
This isotopic system is used to date core formation because the parent is lithophile while the daughter is siderophile.
What is the Hafnium-Tungsten system?
This bedform forms in supercritical flows where the Froude number is greater than 1.
What is an antidune?
The breakdown of muscovite in the presence of quartz marks the transition from the amphibolite facies to the granulite facies at this metamorphic boundary.
What is the second sillimanite isograd?
This class of point groups lack improper rotation, so such crystals can rotate the plane of polarized light passing through them.
What are enantiomorphic point groups? (Also accept: chiral)
In the high-pressure mantles of sub-Neptunes, water ice transitions into this superionic phase, where hydrogen ions flow freely through a lattice formed by oxygen atoms.
What is Ice XVIII (18)?