Skip to main content
Banner Image

ERS321: Past and Present Global Change

Geological Society of America (GSA) Style

Here are a few key items for citing in GSA Style:

  • A "References Cited" section should be included at the end of your paper. This section lists those materials that you actually used and cited in your text, figures, captions, tables, and appendices. 
  • In the "References Cited" section list references alphabetically by author’s last name. For references with two authors, list alphabetically by first author and then alphabetically by second author. For references with more than two authors, list alphabetically by first author and then chronologically, earliest year first.  For references with more than 10 authors, shorten the author list to the first author’s name plus “et al.”
  • Do not include full first names for authors. References should include full last name and initials for first and middle initial (if included in paper).
  • If there are multiple authors, separate the authors with a comma and place and before the last author.
  • Spell out journal titles and book publishers. Include the city of publication for books.
  • Include DOI numbers when available.
  • Nothing in a citation in this style is bolded or italicized EXCEPT for the word in when citing a book chapter.

In-text citation

When writing a paper using GSA style, exact quotes may be used but they must be properly cited within the text using quotation marks, and must include the author's last name, the year of publication and the page number where the quote is from. 

Quotations and paraphrasing may be indicated in one of two ways with this style: 

1. Begin the sentence with the author's last name followed by the date of publication in parentheses. If the information is being paraphrased that is sufficient. If the information includes a direct quote, at the end of the quote include the page number(s) in parentheses.

According to Thuna (2016), the earth is very old.

According to Thuna (2016), "the earth has been around for 4.543 billion years." (p. 205).

2. The other option is to place the name of the author and the publication year at the end of the sentence. 
The earth is very old (Thuna, 2016).
"The earth has been around for 4.543 billion years." (Thuna, 2016, p.205).

When an in-text citation has more than one author, here are some guidelines:

Two authors: Include the last names of both authors.

Three to five authors: Include the last names of all the authors the first time you cite the paper. If you cite the paper again, list only the last name of the first author followed by et. al.

Six or more authors: For all citations, use only the last name of the first author followed by et. al.

Examples of GSA style

Journal Article

Arias, O., and Denyer, P., 1991, Estructura geológica de la región comprendida en las hojas topográficas Abras, Caraigres, Candelaria y Río Grande, Costa Rica: Revista Geológica de América Central, no. 12, p. 61–74. 

Balco, G., Stone, J.O., and Mason, J.A., 2005, Numerical ages for Plio-Pleistocene glacial sediment sequences by 26Al/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. 

Author(s) Last Name(s), Initial(s)., Year of publication, Article Title: Journal Title, Volume number, Page numbers. doi (if available).

Entire Book

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. 

Author(s) Last Name(s), Initial(s)., Year of publication, Book Title:Place of publication, Publisher, Number of pages.

Book Chapter/Paper in multi-author volume

Shipboard Scientific Party, 1987, Site 612, in Poag, C.W., Watts, A.B., et al., Initial Reports of the Deep Sea Drilling Project, Volume 95: Washington, D.C., U.S. Government Printing Office, p. 31–153. Taylor, J.C.M., 1990, Upper Permian—Zechstein, in Glennie, K.W., ed., Introduction to the Petroleum Geology of the North Sea (third edition): Oxford, UK, Blackwell, p. 153–190. 

Author(s) Last Name(s), Initial(s)., Year of publication, Chapter name, in Editor name, ed., Book title: Place of publication, Publisher, Number of pages.

Report

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. 

Author(s) Last Name(s), Initial(s)., Year of publication, Report Title: Publisher, Volume (if applicable), Number of pages, url if available.