Session Number

G953

Advisor(s)

Paul Mayer, The Field Museum of Natural History

Location

B-206 Lecture Hall

Start Date

28-4-2016 1:10 PM

End Date

28-4-2016 1:35 PM

Disciplines

Earth Sciences

Abstract

Silurian (Wenlock) fossil reefs from the Racine Formation in Illinois measure over 100 meters tall and draping flanks beds extend over a mile. Biodiversity studies of reefs in Southeastern Wisconsin reveal complex, diverse communities with over 191 species. We hypothesized that the larger reefs reflect a more optimal environment and may have had higher diversity than reefs in Wisconsin. We compared diversity between the reefs using, identified fossils from the Field Museum, which were collected in Herscer, Romeo, Thornton, Bridgeport, and Hawthorn. Then we compared the results with those from Watkin’s (1997) counts, collected from Horlick, Ives, Franklin, and Francy quarries. We also collected an unbiased bulk sample from Thornton quarry and compared it to unbiased samples from Wisconsin. We found that the unbiased samples had greater differences than the museum collections when compared. The most variable group are echinoderms, In Watkin’s bulk sample data, Echinoderms ranged from 0-22% of the Fauna, in the ours they accounted for 55% of the fauna. Selected samples also showed large amounts of variation in reef composition. This could be due to museum bias for larger specimens, each locality could represent different reef communities, or because Watkin’s had a larger sample size.

Share

COinS
 
Apr 28th, 1:10 PM Apr 28th, 1:35 PM

Comparing Biodiversity of Silurian Reefs in Illinois and Wisconsin Using Museum Collections and Unbiased Bulk Samples

B-206 Lecture Hall

Silurian (Wenlock) fossil reefs from the Racine Formation in Illinois measure over 100 meters tall and draping flanks beds extend over a mile. Biodiversity studies of reefs in Southeastern Wisconsin reveal complex, diverse communities with over 191 species. We hypothesized that the larger reefs reflect a more optimal environment and may have had higher diversity than reefs in Wisconsin. We compared diversity between the reefs using, identified fossils from the Field Museum, which were collected in Herscer, Romeo, Thornton, Bridgeport, and Hawthorn. Then we compared the results with those from Watkin’s (1997) counts, collected from Horlick, Ives, Franklin, and Francy quarries. We also collected an unbiased bulk sample from Thornton quarry and compared it to unbiased samples from Wisconsin. We found that the unbiased samples had greater differences than the museum collections when compared. The most variable group are echinoderms, In Watkin’s bulk sample data, Echinoderms ranged from 0-22% of the Fauna, in the ours they accounted for 55% of the fauna. Selected samples also showed large amounts of variation in reef composition. This could be due to museum bias for larger specimens, each locality could represent different reef communities, or because Watkin’s had a larger sample size.

 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.