Tiny fossils, big impact; the role of Foraminifera-enriched condensed section in arresting the movement of a large retrogressive submarine landslide in the Gulf of Mexico

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doi: 10.1007/978-3-319-20979-1_48
Author(s): Sawyer, Derek E.; Hodelka, Bailee
Author Affiliation(s): Primary:
Ohio State University, School of Earth Sciences, Columbus, OH, United States
Other:
University of Kentucky, United States
Volume Title: Submarine mass movements and their consequences; 7th international symposium
Volume Author(s): Lamarche, Geoffroy, editor; Mountjoy, Joshu J.; Bull, Suzanne; Hubble, Thomas; Krastel, Sebastian; Lane, Emily M.; Micallef, Aaron; Moscardelli, Lorena; Mueller, Christof; Pecher, Ingo A.; Woelz, Susanne
Source: Advances in Natural and Technological Hazards Research, Vol.41, p.479-486; 7th symposium on Submarine mass movements and their consequences, Wellington, New Zealand, Nov. 1-4, 2015, edited by Geoffroy Lamarche, Joshu J. Mountjoy, Suzanne Bull, Thomas Hubble, Sebastian Krastel, Emily M. Lane, Aaron Micallef, Lorena Moscardelli, Christof Mueller, Ingo A. Pecher and Susanne Woelz. Publisher: Springer, Dordrecht, Netherlands. ISSN: 1878-9897. ISBN: 978-3-319-20979-1
Note: In English. 10 refs.; illus., incl. geol. sketch map, sects.
Summary: A 3.4-m thick condensed section enriched in foraminifera formed the final detachment horizon of a retrogressive submarine landslide, in the Ursa Basin, northern Gulf of Mexico. The high concentration of foraminifera produces a high porosity (up to five porosity units) layer distinct from the background clay. Integrated Ocean Drilling Program Expedition 308 Site U1324 cored and logged this layer. We conducted a sedimentological analysis on 31 samples across this zone and the overlying and underlying background clay. CT images show that foraminifera are individuals dispersed within the clay, unbroken, and have retained a significant amount of intraskeletal void space. The assemblage is expected for this time interval in the Late Pleistocene (∼24 kya). We interpret the layer is a result of a pause in terrigenous sedimentation. The condensed section was a preferred detachment horizon but only minimal sliding occurred before further movement ceased. One possible mechanism to explain this is the presence of foraminifera results in a dilational shear strengthening behavior, which arrested movement. Further work will be required to test this, however. On a broader scale, condensed sections with abundant microfossils, may play a key role in landslide mechanics because they can alter the shearing properties of the background material.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 06 Petrology, Sedimentary; 23 Surficial Geology, Geomorphology; Atlantic Ocean; Cenozoic; Clastic sediments; Clay; Expedition 308; Foraminifera; Fossils; Geomorphology; Gulf of Mexico; IODP Site U1324; Integrated Ocean Drilling Program; Invertebrata; Landslides; Mass movements; Microfossils; North Atlantic; Ocean Drilling Program; Pleistocene; Porosity; Protista; Quaternary; Retrogressive landslides; Sedimentation; Sedimentology; Sediments; Shear; Shear strength; Slumping; Upper Pleistocene; Ursa Basin
Coordinates: N280500 N280500 W0890800 W0890800
N280000 N283000 W0890000 W0900000
Record ID: 2016091764
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.