Geological Society of America

19 D8. Paleontology (Posters)

Tuesday, 26 March 2019
8:30 AM - 5:45 PM
Big Basin/Kaw Nation Rooms

CORAL-ALGAL COMPETITION ON TERTIARY REEFS: GREENHOUSE TO ICEHOUSE TRANSITIONS

Paper number: 19-3
Program: Technical Sessions
Time: 8:30 AM – 5:45 PM

Authors

Belkasim Khameiss Presenting Author
Ball State University, Muncie, IN
Richard Fluegeman
Ball State University, Muncie, IN
Ahmed Muftah
University of Benghazi, Faculty of Science, Benghazi, IN
William H. Hoyt
Univ of Northern Colorado, Greeley, IN
Shawn Malone
Ball State University, Muncie, IN
Jeffry Grigsby
Ball State University Environment, Geology, & Natural Res., Muncie, IN
Randall Bernot
Ball state University, Muncie, IN
Tykhon Zubkuf
Ball state University, Muncie, IN
Saad K. El Ebaidi
University of Benghazi, Faculty of Science, Benghazi
Saad K. El Ebaidi
University of Benghazi, Faculty of Science, Benghazi, IN

Abstract

The competition between coral and algae is pervasive through geologic time; that competition determines the structure and composition of reef communities which we see in the fossil record. However, the relationships between coral and calcareous algae in reefs is poorly understood. To study this relationship, several samples were examined from seven different Paleogene foralgal reef localities around the world. Section one is Salt Mountain, Alabama, which preserves a Paleocene reef,15m thick. Section two is the Utoe Limestone, New Caledonia. It is Middle Eocene in age, it 16.37m thick. Section three is IODP site U1376, IIA Limestone.The age of this section is Middle Eocene, it is 15.63m thick core. Section four is the Darnah Formation in the West Darnah Road-cut section, it is 57m thick . It is Middle Eocene in age. Section five, the Al Baydah Formation, it is11m thick. Section six , The Early-Middle Miocene Al Faydiah Formation (Al Fatayah Cemenet Quarry)7m thick. Section seven, The Early-Middle Miocene Benghazi Al Formation (Benghazi Cement Quarry)12m thick.

Based on the results, we determine the occurrence and outcomes of coral-algal interactions among different coral growth forms The Paleocene-Eocene has the highest percentage of the algae in the two forms, which is a good indicator of warm climate. In the Middle Eocene to Late Eocene, the coral replaced the algae in different localities inside sections of that age. This change is an indicator for climatic cooling, especially in the west Darnah section of Lutetian age. In Oligocene time, high branching corals became abundant and escaped competition with the algae due to Icehouse conditions, as shown in the Al Baydah Formation. In the Miocene, coral species started to decline because of the return to Greenhouse conditions. The coral loses its competitive edge when chemical and physical defense systems reduce growth due to warming. On the other hand, crustose form algae attract the larvae of the coral. Algae induce them to get a fondose form which is useful for them as they decrease growth and production. Algae easily colonize the dead reef by using the firm substrate to rebuild themselves. This research may prove valuable when predicting the response of modern coral reef systems to future climatic warming conditions and provides a model for what future reefs may look like.

Geological Society of America Abstracts with Programs. Vol. 51, No. 2

doi: 10.1130/abs/2019SC-326622

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