Skip to Main Content
Skip Nav Destination

Abstract

The Morrison Formation is a laterally extensive terrestrial deposit representingan ecologically diverse assemblage of paleoenvironments from the Late Jurassic ofwestern North America. Although the Morrison Formation has recently been interpretedas a semiarid lowland savannah on the basis of geological and paleobiologicalindicators, many microenvironments within this system are more consistent with newinterpretations of the Morrison as a ground-water dominated “wetland” deposit. Herewe report new fossils from a little-studied exposure of the Morrison Formation in andaround Temple Canyon Park near Cañon City, Colorado. The Temple Canyon sectionshows a relatively thin sequence of conglomerate, sandstone, siltstone, mudstone, andlimestone beds representing alluvial to fluvial and possibly lacustrine deposition. Thesection rests on Precambrian basement and is unconformably overlain by the LowerCretaceous Lytle Formation. The mudstone and limestone beds preserve an abundantfossil flora and fauna distinct from those previously described from the MorrisonFormation. The floral assemblage includes species of algae, bryophytes, ferns, ginkgophytes,horsetails, cycads, bennettites, and conifers; together these plants indicatea warm climate with abundant local water supply. The faunal assemblage containsostracodes, conchostracans, traces of aquatic insect larvae, a terrestrial insect bodyfossil, prosobranch and pulmonate gastropods, many species of fish, a possible frog,and rare turtle remains. The presence of prosobranch gastropods, fish, and aquaticinsect larvae suggests a perennial water body with high oxygen content, while thepresence of conchostracans and pulmonate gastropods may indicate some fluctuationin water quality.

Keywords: Morrison Formation, Jurassic, Cañon City, Colorado, paleoecology.

You do not currently have access to this chapter.

Figures & Tables

Contents

GeoRef

References

Related

Citing Books via

Close Modal

or Create an Account

Close Modal
Close Modal