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Welcome

If you are not a member and are visiting this web site, we hope that you will join us. Come to some of our meetings (no charge)and visit with our members. We have excellent speakers, presentations, and socializing.

Starting in 2018, enter through the Leprino Atrium on the west side of the museum. Doors open at 6:30 p.m.,meetings begin at 7 p.m.

Meetings are held either in the Ricketson Auditorium or the Planetarium at the Denver Museum of Nature & Science, unless otherwise noted.


  • Monday, January 8, 2018
  • Gates Planetarium, Denver Museum of Nature & Science

  • Speaker: Vikki Crystal

  • Vertebrate and invertebrate stable isotope insights into fluvial landscapes and hadrosaur behavior in the Late Cretaceous of southern Utah

Abstract During the Late Cretaceous, western North America was flooded by an inland sea, the coast of which was comprised of broad, low-relief fluvial/alluvial plains on which a wide variety of flora and fauna lived. While there is knowledge about the presence of hadrosaurs, ceratopsians, theropods and plants, the details of paleohydrology and its impact on dinosaur behavior are not known for certain. In this study, stable isotopes of vertebrate and invertebrate material collected from microsites within the Kaiparowits Formation in southern Utah were used to investigate the nature of the hydrological systems and behavior of dinosaurs over these landscapes. Differences in stable isotope ratios of gar ganoine, and enamel from hadrosaur teeth, and authigenic micrite, in conjunction with previously published bivalve data, indicate that there are three main parts of the fluvial system: large anastomosing rivers draining upland areas, smaller streams draining the foreland basin, and lakes subject to episodic flooding. Furthermore, it is possible to infer the mixing of water among these sources, in particular, the mixing of the large rivers and small streams, presumably during seasonal flooding events that were analogous to processes taking place in modern-day Tonle Sap Lake in central Cambodia. The soils along the margins of the lakes were characterized by episodic flooding and saturation, with those closer to the margin being saturated for a longer period of time, compared to more distal localities. Furthermore, hadrosaurs that ate vegetation located closer to the lake margin have teeth with higher carbon isotope ratios than teeth of hadrosaurs consuming vegetation more distally. This suggests a difference in habitat use among hadrosaur populations within low-lying fluvial environments in southern Utah during the Late Cretaceous. Thus, variations in the hydrology of these fluvial systems appears to have played an important role in determining the distribution of plants and dinosaurs over Kaiparowits landscapes.

About the Speaker Victoria (Vikki) Crystal is currently a graduate student at the University of Colorado Boulder, pursuing her PhD in geology. Vikki first became interested in paleontology and geology during childhood visits to the Prehistoric Journey exhibit at the Denver Museum of Nature and Science. Vikki attended Colorado College, where she graduated in 2014 with a BA in Geology. She also studied abroad in New Zealand, where she participated in the Frontiers Abroad Geology Program. After graduating, Vikki worked at Colorado College as a paraprofessional for the Geology Department, where she assisted the department with coursework, field trip planning, and other collaborative departmental projects.

Along with geology and paleontology, Vikki is also passionate about education. She is a certified Environmental Educator and has spent summers teaching science and leadership at the Keystone Science School and the Logan School for Creative Learning. In her spare time, she enjoys hiking, knitting, and baking cookies.