According to Discovering the World through Debate, a "causal argument" is "An argument that supports associations between causes and effects" (246). Related concepts include: Contributory causal argument, intervening and counteracting causal argument, necessary causal argument, and sufficient causal argument.
Trapp, Robert, et al. Discovering the World through Debate: A Practical Guide to Educational Debate for Debaters, Coaches, and Judges. Third Edition. New York: IDEA Press Books, 2005.