Geobiology and Sedimentary Systems
- Ph.D., 1961, University of Michigan
- M.S., 1956, University of Michigan
- B.S., 1955, University of Michigan
My research activities are subdivided equally between five spectra, all designed to give a regional picture of the distribution of communities along an environmental stress gradient during the Cretaceous: 1) In the Bivalvia and Ammonoidea, a systematic revision of the species-subspecies levels, to provide additional tools to biostratigraphy. 2) Carrying my finely tuned biostratigraphy across the border from Montana and into Canada, the north-temperate realm, to evaluate changes that can be discerned in progressively more northerly latitudes. Changes that are evident in a first test case are decrease in diversity, but increase in numbers of the taxa that remain in the relict fauna, the Inoceramidae. Regardless of facies, whether carbonate (as is prevalent in the south) or siliciclastic (prevalent in the north) in defining the changes in background biotas, it is always toward a simpler biota in a more northerly direction, with lesser numbers of everything except Inoceramidae, and a greater mass of these bivalves. 3) In a north to south direction, there is a marked increase in diversity. From one or two zones in Tethys depending on the level of the sea; diversity peaks occurred during the late Lower Cretaceous-early Late Cretaceous, during the Upper Cretaceous (Middle part, Conacian-Santonian), and for latest Cretaceous when the diversity almost doubled among rudistids. 4) A maximum flooding surface has been dissected from middle Canada to the Caribbean; all of northern Canada is inoceramid-rich, most of the U.S.A. has a more diverse fauna, diversity increases to the south. The southernmost faunas extend to the equator (Northern Tropics) are characterized by rudists along with a diverse molluscan fauna which shows a double peak, one at the edge of the tropics and one within the tropics, marking the supertropical zone characterized by rudists. The inner two are sharply bounded, the rest are graded. 5) There are a series of faunal zones which can be correlated between ocean basins in the Cretaceous, so that truly global correlations are possible at less than a million years in magnitude.
I further seek to define the gradient at this time in history as the antithesis of today's icehouse world. During the Cretaceous, the Earth had fewer climate zones, and they were more widely spread, with cold temperate climates extending to the poles in this greenhouse world.
Elswick, E.R., and Johnson, C.C., (2008, in press) A siliciclastic diamictite from the Maya Mountains, Belize. Journal of South American Earth Sciences.
Kauffman, E.G., and Swado, J.K., (2008, in press) A Mosasaur-Predated Nautiloid from the Maastrichtian Pierre Shale, Central Colorado, Western Interior Basin, USA. Lethaia.
Puchalski, S.S., Johnson, C.C., Kauffman, E.G., and Eernisse, D.J., (2008 in press) A new genus and two species of multiplacophorans (Mollusca, Polyplacophora, Neoloricata), Mississippian (Chestrian), Indiana. Journal of Paleontology.
Kauffman, E.G., and Johnson, C.C., (2009) Cretaceous warm climates. V. Gornitz, Editor. Encyclopedia of Paleoclimatology and Ancient Environments. Kluwer Academic Publishers, p. 213-217.
Puchalski, S.S., and Johnson, C.C., (2008) Preservation Potential of Katharina tunicata and Mopalia muscosa (Mollusca, Polyplacophora). Lethaia. DOI 10.1111/j.1502-391.2008.00125.x
Puchalski, S.S., Eernisse, D.J., Johnson, Claudia C., (2008) The effect of sampling bias on the fossil record of chintons (Mollusca, Polyplacophora). American Malacological Bulletin 25, p. 87-95.
Johnson, Claudia C. Association of paleoenvironment and evolutionary grade of reef constructors through the Phanerozoic. Abstract, 2008 Joint Meeting Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Assoc. Geol. Societies with Gulf Coast Section SEPM.
Budziak, A., Beeker, C. de Leon, R., Johnson, C., and Kauffman, E. From barrels to augers: Managing a transition in the mooring buoy systems of Bonaire National Marine Park. Abstract, International Coral Reef Symposium, Reefs for the Future, July 7-11, Ft. Lauderdale, Florida, USA.
Johnson, Claudia C., Beeker, Charles D., Budziak, Anna T., Stewart, Joshua D., and Kauffman, Erle G., Coral recruits on submerged cultural artifacts, 1724 Guadalupe Underwater Archaeological Preserve, Dominican Republic. Geological Society of America Abstracts with Program, Vol. 39, No. 6, p. 404.
Johnson, C.C., and Kauffman, E.G., (2006) Bivalve, rudist. AccessScience2006; DOI 10.1036/