T

tableland

tachylyte

TAI See THERMAL ALTERATION INDEX.

technique

tectonostratigraphic, tectonometamorphic

tendency

tends to Tends to is incorrectly used in such expressions as: 'the vein tends to split' or 'the fault tends to swing to the north'. Either the vein splits or it does not, and, similarly, either the fault swings or it maintains its course. The expression is used correctly in the sentence: dispositions tend to change with age.

tense See 'Verbs' in 'Grammar'

terrain, terrane Terrain refers specifically to a 'topographic surface'. Terrane refers to 'the general area or body of a type or grouping of rock, by age, formations, or lithology, especially metamorphic or structural groupings': a gneissic terrane, a Precambrian terrane, Bancroft terrane, Elzevir terrane.

terrigenous

testhole

tetrahedron (pl. tetrahedra)

thalweg

that, which These relative pronouns are commonly misused for each other. See 'Pronouns' section in 'Grammar'.

the The definite article the is generally unnecessary in association with the names of streams, valleys, or other physiographic or topographic features, such as: (the) Mackenzie River, (the) Fraser River valley, (the) Porcupine Creek, (the) Sverdrup Basin, though the ruling is not absolute and, in some instances, custom prefers the retention of the definite article, as in: the Rocky Mountains, the Coast Range, the Great Lakes, the Great Plains, the Prairie provinces. Use the in such expressions as: the Mackenzie, the Liard River bridge, and the Bearpaw Formation.

there is, there are (there was, there were, etc.) See 'Jargon and contrived or redundant words' in 'Grammar'.

Thermal Alteration Index (TAI) There are Thermal Alteration and Colour Alteration indices, but do not use 'Thermal Alteration Indices' when referring to a series of values or measurements. The latter should be written Thermal Alteration Index values, or, TAI values.

these kind, these sort, those kind, those sort The correct expressions are: this (that) kind, this (that) sort; these (those) kinds, these (those) sorts.

thick, thickness The expression, the beds are 2 to 3 m thick is preferable to 'the beds are 2 to 3 m in thickness', but no choice is allowed in the expression: the beds vary in thickness from 2 to 3 m.

thick bedded, thin bedded Use hyphens when the compound functions as an adjective before a noun, but not elsewhere: A thick-bedded sandstone, as opposed to a 100 m thick, bedded sandstone. The unit is thin bedded, chiefly composed of beds less than 10 cm thick.

thickening-upward cycles, thickening-upward sequences (not upward-thickening sequences, or thickening-up sequences)

thinly bedded limestone (prefer thin-bedded limestone)

thin section

third order (n.), third-order (adj.)

this, that Should never be used adverbially (as in 'this much').

tholeiite, tholeiitic

though, although Both forms are correct, though the shorter is commonly preferred.

three-dimensional, third dimension

thrust fault, but McConnell Thrust, or McConnell Fault, and McConnell thrust fault

tidewater

till See UNTIL.

timberline

time comparisons See EARLIER, LATER.

time domain, but time-domain electromagnetic method

time-stratigraphic

time terms Time words, chiefly adverbs, should not be used to denote abundance or distribution (space or place terms). The time terms listed here should be replaced by the corresponding space terms that are italicized in brackets: always (everywhere), frequently (commonly), never (nowhere), occasionally (locally, here and there), often (commonly, in many places), seldom (rarely), since (as, because), sometimes (in places), usually (commonly, most of), when (where), and while (although, whereas).

Some examples are shown in such sentences as: 'While (Although) others may disagree, I am prepared to defend this usage'; 'When (Where) the fault swings to the west'; or 'Since (As) the shaft is caved, no examination can be made'. They are correctly used in: While I am away you...; When the first assays were run...; or, Since the first World War, prices.... You may visit outcrops frequently (not commonly). Sandstones are commonly feldspathic (not often feldspathic). Beach deposits may show evidence of occasional (or frequent) storm influence, but the same deposits rarely (or commonly) contain storm-generated sediments.

Note that throughout can be used for time and space.

Timiskaming A geographical area in Ontario, but 'Témiscamingue' a geographical area in Quebec. Timiskaming Group, and Lake Timiskaming (Ontario), lac Témiscamingue (Quebec). See 'Names of pan-Canadian significance' in 'Preparing maps and reports for publication'.

TIMS Abbreviation for thermal-ionization mass spectrometry

titles Titles such as Dr., Mr., etc., are better omitted. Authors must be careful that names, initials, and titles of persons, companies, or organizations are cited correctly.

tonne (1 tonne = 1.1 short tons). Use the SI symbol 't'.

too, very These words do not qualify participles directly. The word much should be inserted; as in too much engrossed, or very much pleased. See also VERY.

topographic (not topographical)

topsoil

toward, towards Either is acceptable. Be consistent.

township Capitalized as in Fitzroy Township, and the Eastern Townships, but Tiny and Tay townships

traceable

transatlantic, transcontinental, but trans-Arctic

transfer, transferable, transferred, transferring

transpire In its nontechnical sense, transpire means 'become known' (not happen).

travel, travelled

traveltime

treatise, pl. treatises

treeline

Trempealeauan

trickle-down theory

tricolpate, tricolporate The adjective tricolpate refers to 'pollen with three colpae without pores'. The adjective tricolporate refers to 'pollen with three colpae, each of which has a central pore'.

trillion This word signifies 10¹² in North America, but 10¹⁸ in most other countries. Because of this ambiguity, the term trillion should not be used. See also BILLION; QUADRILLION.

trimline

tsunami

tuff breccia

T-wave

twentieth century (not Twentieth Century)

twenty-first century (not Twenty-First Century)

two-person tent

type section

Type III kerogen

typical See CHARACTERISTIC.