Abstract Detail

Paleobotany

Kelly, Brooke [1], Ryberg, Patricia Elizabeth [2].

Floral analysis of a Pennsylvanian floodplain ecosystem, Parkville, MO, USA.

During the Pennsylvanian (323–299 Ma), environments of North America ranged from coal swamps to flood plains, and even some slightly drier environments, such as clastic, terra-firma lowlands. The dominance of one of the five plant groups of this period (lycopsids, ferns, sphenopsids, pteridosperms, cordaitaleans) provides clues as to the type of ecosystem present in the deposit. For example, lycopsids dominated coastal coal swamps while cordaitaleans dominated drier upland habitats. An outcrop in the central part of the United States; Parkville, MO, USA (39.19° N, 94.68° W) reveals the retreat of the Panthalassic Ocean in the Late Pennsylvanian as marine deposits grade into shales in which the plant flora changes from a coastal environment through a floodplain flora and finally a probable upland environment. The preservation of the fossils is pristine providing exquisite detail on both vegetative and reproductive features. Quantitative analyses were performed on plant fossils from this outcrop to determine the abundance and diversity of the flora, however stratigraphic position within the outcrop was not considered in this study. This quantitative study presents the initial results of the diversity of the flora present throughout all the layers in the outcrop. The abundance of each genus present was determined by examining the paleobotanical collections at Park University and the University of Kansas, Lawrence. The dominant group were Medullosans (34%) represented by Neuropteris and Odontoperis foliage followed by the Sphenophytes (24%). Cordaitaleans and lycopsids each represented less than 20% of the diversity. Contemporaneous environments that have been reconstructed as floodplains show a dominance of medullosans close to active channels and sphenophytes in wetter areas near abandoned channels and ponds. Preliminary examination of the stratigraphic distribution of the medullosans and sphenopsids in the Parkville outcrop indicates a river/deltaic system with active channels (medullosan dominated) alternating with abandoned channels (sphenopsid dominated). Future studies aim to study the dynamic changes of the environment as the ocean receded and more upland habitats formed.

1 - Park University, Department of Natural & Physical Sciences, Parkville, MO, 64152, USA
2 - Park University, Department of Natural & Physical Sciences, 8700 NW River Park Drive, Parkville, MO, 64152, USA

Keywords:
Pennsylvanian
Missouri
Diversity
Pteridosperms
Sphenophytes.

Presentation Type: Oral Paper
Session: 12, Cookson/Moseley award presentations
Location: Sundance 4/Omni Hotel
Date: Monday, June 26th, 2017
Time: 2:45 PM
Number: 12006
Abstract ID:280
Candidate for Awards:Isabel Cookson Award