Follow your professor's instructions for how to format your paper above all!
Communicating rocks : writing, speaking, and thinking about geology / by Peter Copeland
Geowriting : a guide to writing, editing, and printing in earth science / edited by Robert L. Bates, Marla D. Adkins-Heljeson, and Rex C. Buchanan
The craft of scientific communication / Joseph E. Harmon & Alan G. Gross
A field guide for science writers / edited by Deborah Blum, Mary Knudson, Robin Marantz
A few examples using GSA style (from the GSA style guide):
Balco, G., Stone, J.O., and Mason, J.A., 2005, Numerical ages for Plio-Pleistocene glacial sediment sequences by 6Al/10Be dating of quartz in buried paleosols: Earth and Planetary Science Letters, v. 232, p. 179–191, doi:10.1016/j.epsl.2004.12.013.
Allmendinger, R.W., Cardozo, N., and Fisher, D., 2011, Structural Geology Algorithms: Vectors and Tensors in Structural Geology: New York, Cambridge University Press, 304 p.
Willingham, C.R., Rietman, J.D., Heck, R.G., and Lettis, W.R., 2013, Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California: Chapter CC of Evolution of Sedimentary Basins/Onshore Oil and Gas Investigations–Santa Maria Province: U.S. Geological Survey Bulletin 1995-CC, 105 p., http://pubs.usgs.gov/bul/1995/cc/pdf/bul1995cc.pdf.
Bayley, R.W., and Muehlberger, W.R., compilers, 1968, Basement rock map of the United States, exclusive of Alaska
and Hawaii: U.S. Geological Survey, scale 1:2,500,000, 2 sheets.
Citations can be tricky! Feel free to ask for help!