Lectures 2-5 Flashcards
Absolute date
A quantification for how old something is (albeit with error)
Boulder clay
Glacial deposit
Cirque
Bowl-shaped cavity on hillside with steep, cliff-like tops and shallow bottoms formed by ice
Daughter element
Element produced by radioactive decay
Devensian
The last glacial period (70Ma)
Diatom
Single-celled alga (aquatic plant) with a wall of silica
Dropstone
Large rock in fine-grained sediment thought to have been deposited by falling from a melting iceberg
Foraminifera
Single-celled aquatic animal with a CaCO3 shell
Freeze-thaw
Weathering that results from the expansion and contraction of material as it experiences temperature fluctuations around 0C
Gondwanaland
An ancient supercontinent
Green house
When Earth is relatively ice-free
Half-life
Time taken for one half of the original number of radioactive atoms to decay
Holocene
Last 11.7ka interglacial period (in which we live)
Horn
Three or more cirques back-to-back
Ice house
When Earth had ice at least covering high latitudes
Ipswichian
Penultimate interglacial period
Isotopic Age
Time since the isoptopic clock was ‘reset’ when isotopes were locked into the minerals (ie crystallisation after melting)