GSA Connects 2021 in Portland, Oregon

Paper No. 166-9
Presentation Time: 3:45 PM


VIEIRA, Justin, Rowan University Geology, 400 Edgewood Park, Glassboro, NJ 08028-1658 and ULLMANN, Paul, Geology, Rowan University, 201 Mullica Hill Rd., Glassboro, NJ 08028

Shallow-marine strata at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, NJ, capture a high-resolution record of transition between Cretaceous and Paleocene ecosystems and their faunas. To explore changes in faunal ecology due to the K/Pg extinction at this locality, we synthesized information on the modes of life of invertebrate taxa preserved in three fossil layers within the quarry and examined whether these attributes affected survivability across the Cretaceous-Paleocene boundary (KPB). Incorporating recent discoveries into prior faunal lists yielded a total of 67 invertebrate species for this study, which derive from a late-Danian upper Hornerstown fossil layer, the early-Danian Main Fossiliferous Layer (MFL), and consideration of taxa found within Maastrichtian Navesink Formation as a third ensemble community. Modes of life were defined based on primary habitat (e.g., epifaunal), feeding style (e.g., carnivore), and degree of motility (e.g., sessile). Through graphical analyses of the dataset as a whole and in smaller taxonomic partitions, we identified clear evidence of drastic transitions in benthic invertebrate modes of life across the KPB. Molluscs are the most prevalent invertebrates in all three fossil layers. Invertebrate taxa could be classified into 13 modes of life, nine of which became extinct following deposition of the MFL. Motile carnivores flourished in the MFL, likely capitalizing on a brief surplus of organics deposited on the seafloor following the Chicxulub impact, then the local fauna became dominated by nonmotile, nonplanktotrophic suspension feeders in the later Danian, as documented by prodominance of sponges, brachiopods, and the coral Flabellum in the upper Hornerstown fossil layer. Deep infaunal species and deposit feeders did not survive after deposition of the MFL at Edelman Fossil Park, suggesting that they may have succumb to a scarcity of nutrient resources in post-impact oceans and/or other K/Pg extinction-related ecological stresses. Our quantitative assessments of invertebrate survivorship trends across the KPB at Edelman Fossil Park, and comparative analyses to other shallow-marine KPB localities will reveal whether these trends represent global patterns.