Colons can be used:
This essay will discuss three possible contributing factors to the London Riots: social media, issues of social identity, and dissatisfaction resulting from perceived inequality.
James (2012) is dismissive of Kingsley Amis's approach: ' How could one be guiltless of them all?'
The paper raises one important question: how could these problems be addressed?
In the survey, people living in the area reported that their major concerns were as follows: lack of good quality public transport links; distance to the nearest hospital or medical centre; lack of career opportunities to encourage young people to stay in the area; and the uncertain future of the agricultural industry.
Semi-colons can be used to separate two complete sentences that are very closely connected. The clauses either side of a semi-colon should be able to stand alone and still make sense. For example:
Talks were conducted against a background of increasing distrust; relations between the two countries subsequently deteriorated.
Try not to use too many semi-colons in your academic writing. Often a full stop is clearer. However, semi-colons can be useful to show a strong link between two sentences or ideas.