Earth Heritage Glossary

Welcome to the CCW Earth heritage glossary index page. Over the next year or so, we will be adding more and more terms to the Earth Heritage glossary, and our other glossary chapters.

To find a specific glossary term, try entering the word into the main glossary search box in the right-hand column of the website.

Failing that, you can look for a term by browsing through the glossary index alphabetically, below.

Earth Heritage

A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z

Glossary for letter: I

Iapetus Ocean: A former ‘proto-Atlantic’ ocean that separated the crustal plates of Laurentia and Gondwana (including Avalonia which contained Wales) during early Palaeozoic times.
Igneous Rock: One of the three main groups of rock type (sedimentary, metamorphic and igneous) and used to describe a rock that has solidified from molten or partially molten material (magma).
Ignimbrite: From the Latin terms ignis, meaning fire, and nimbus meaning cloud equivalent to an ash-flow tuff, a poorly sorted pyroclastic rock.
Inlier: An area of older rocks completely surrounded by younger rocks, and resulting from faulting or folding followed by erosion.
Interglacial: A period of relatively warm temperatures between glacial phases, during which ice-sheets and glaciers retreated and sea-level rose.
Intermediate rock: an igneous rock whose geochemical composition lies between that of basic and acid rocks, for example an andesite.
Intrusion: a body of igneous rocks that has been introduced into pre-existing rocks
Island arc: a series of volcanoes that lie on the continental side of an ocean trench at which there is a subduction zone.
Isotopic dating: the technique of determining the age of rocks or fossils from the relative proportions of a radioactive parent element and its decay product(s).
Isotopic dating: the technique of determining the age of rocks or fossils from the relative proportions of a radioactive parent element and its decay product(s).