A manual for writers of research papers, theses, and dissertations, Ninth edition - Kate L. Turabian 2018

Colons
Punctuation
Style

A colon introduces a clause, phrase, or series of elements that expands, clarifies, or exemplifies the meaning of what precedes it. Between independent clauses, it functions much like a semicolon, though more strongly emphasizing balance or consequence.

People expect three things of government: peace, prosperity, and respect for civil rights.

Chinese culture is unrivaled in its depth and antiquity: it is unmatched in its rich artistic and philosophical records.

Use a colon to introduce illustrative material or a list. A colon should follow only a complete independent clause; often an introductory element such as the following or as follows should precede the colon. (See also 23.4.2.)

The qualifications are as follows: a doctorate in economics and an ability to communicate statistical data to a lay audience.

but not

The qualifications are: a doctorate in economics . . .

Note that the first word following a colon within a sentence is generally not capitalized unless it is a proper noun or unless the colon introduces more than one sentence. For capitalization in quotations introduced by a colon, see chapter 25.

Colons are also used in titles (see 17.1.2 and 19.1.3), in notations of time (23.1.5), in URLs (20.4.2), and in various ways in citations.