PARALLEL INVESTIGATIONS IN THE PALEONTOLOGICAL CAREERS OF RICHARD L. SQUIRES AND MARY MCGANN: SUBMARINE CANYONS/TURBIDITES, WHALE FALLS, METHANE SEEPS, AND BIOSTRATIGRAPHY

I was a student in Richard Squires’ first paleontology class at CSUN and it is possible that he has subconsciously influenced me. Although our research differs in that we specialize in different organisms (mollusks vs foraminifers), time periods (primarily Cretaceous to Eocene vs Quaternary), and fossil localities (terrestrial outcrops vs marine deposits), surprisingly we have investigated many of the same subjects in our paleontological careers. Submarine canyons and turbidites are one common theme. Both of us have identified sediment gravity flows related to overbanking within channel/levee systems, as well as hemipelagic deposition. The former were characterized by the presence of displaced shallow-marine faunas; the latter were used to interpret paleooceanographic conditions (i.e., open ocean vs brackish, water temperature, salinity) interpreted by the mega- and microfaunas present. Whale falls have also been of interest to the two of us. Dick reported on eight Oligocene whales and suggested that the sulfide production associated with whale carcasses supported small numbers of some chemosymbiotic invertebrates as early as 30 million years ago. In addition, he concluded that vertebrate carcasses have probably not contributed significantly to the dispersal of cold-seep and hydrothermal vent invertebrates. One site I studied suggested the foraminiferal fauna under a whale fall was not impacted after five days on the seafloor, whereas another was significantly reduced in species richness and dominated by one species a year later. Furthermore, neither of my sites contained endemic fauna. Both Dick and I have studied the faunas associated with methane seeps. At Oligocene and Eocene sites, he suggested the mollusks represented fossil cold methane seep chemosynthetic communities. At Kimki Ridge in Catalina Basin offshore southern California, I found evidence of continual localized cold methane fluid seepage for at least the last 3,800 years, with two pulses of methane released (at 3,700 and 3,000 cal yr B.P.) that were large enough to influence much of the water column. Finally, biostratigraphy is another common aspect of our investigations. Dick uses the species he encounters to routinely determine the age of the deposits; my colleagues and I are proposing to use invasive organisms to define the Anthropocene.