NPS Paleontology Research Abstract Volume


ASSEMBLAGES OF FOSSIL VERTEBRATES IN PRE-IGNIMBRITE DEPOSITS
OF THE TURTLE COVE MEMBER, JOHN DAY FORMATION,
FROM OUTCROPS WITHIN THE SHEEP ROCK UNIT,
JOHN DAY FOSSIL BEDS NATIONAL MONUMENT, OREGON

Ted Fremd
National Park Service
420 West Main Street
John Day, Oregon 98745

The diagenetic history of lower John Day vertebrates is enigmatic. For the past several years, field workers have been involved in cyclic prospecting and recovery of skeletal material preserved in zeolitized tuffaceous paleosols within the southern portion of Turtle Cove. Grant County, Oregon, and documenting the precise location of in situ specimens on aerial photographs. These and newly-discovered sites are recorded on high resolution color stereo air photographs, and the coordinates, taphonomic data, and stratigraphic information have been compiled using dBase III+ programs. The samples are dominated by hypertraguiids, merycoidodontids, rhinocerotids, canids, felids, and equids, as well as numerous species belonging to 18 other families.
Many of the disarticulated specimens found within certain layers are weathered and abraded, broken, and possess rodent chew marks. Samples from other units suggest burial in varied environments, re-exposure, possible transportation, and reburial in subsequent volcaniclastic episodes.

48th SVP Meeting, Drumheller, Alberta, October 1988.




EARLY MIOCENE MAMMALIAN POPULATIONS FROM TURTLE COVE, OREGON

Ted Fremd
National Park Service
420 West Main Street
John Day, Oregon 97845

Interpreting the taphonomic biases in the biostratigraphic record of the lower John Day Formation (early Arikareean) has been facilitated with the use of detailed prospecting and site recording techniques. Over thirty localities within "The Cove" are narrowly separated both temporally and spatially. Comparisons of taxonomic, skeletal element, and other properties of these assemblages demonstrates a surprisingly diverse array of preservational histories.





51st SVP Meeting, San Diego, California, October 1991.
COOPERATIVE MANAGEMENT OF PALEONTOLOGICAL RESOURCES
IN THE JOHN DAY BASIN, CENTRAL OREGON

Ted Fremd
John Day Fossil Beds National Monument
420 West Main Street
John Day, Oregon 97845

Numerous scientifically significant vertebrate fossils, threatened by erosion and unauthorized collectors, occur on lands administered by the Prineville District of the Bureau of Land Management (PD). These are important localities that add to our knowledge of paleoclimates, mammalian evolution, and global change. The strata are adjacent to boundaries of John Day Fossil Beds National Monument (JODA), which is equipped with the mandate, staff, and equipment to provide research and curatorial services. The NPS has surveyed BLM resource areas for paleontological values, provided identifications and curation of over 500 specimens into the National Catalog System, and provided input into management and planning documents. The BLM helped defray the cost of an NPS museum technician, and has purchased museum cabinetry. Participants jointly funded high-resolution color stereo aerial photography. Other NPS and BLM areas may wish to use this coop agreement as model for partnerships in paleontological stewardship.

The George Wright Society, Jacksonville, Florida, November 1992




CUT-AND-FILL EPISODES IN THE JOHN DAY FORMATION
IN THE PAINTED HILLS AREA OF CENTRAL OREGON

Erick Bestland and Gregory Retallack
Department of Geological Sciences
University of Oregon
Eugene, OR 97403

Ted Fremd
John Day Fossil Beds National Monument
John Day, Oregon 97845

Recent lithostratigraphic mapping in the Painted Hills Unit of the John Day Fossil Beds National Monument in central Oregon has identified mappable subdivisions of the lower John Day Formation as well as refined the local boundary between the John Day and Clarno formations. The boundary between the two formations is placed at the base of a distinctive welded tuff recognized as member A, mapped in the western facies of the John Day Formation. A sequence of basalt flows, exposed directly south of the park, were previously mapped as Clarno but are stratigraphically above member A and are thus part of the John Day Formation.
Several large (200 ft. of relief) intra-formational erosional surfaces are recognized in the lower part of the John Day Formation and separate otherwise conformable units. The sequences between erosional surfaces could be considered members and contain distinctive paleosols which aid in their identification and mapping. Each contains a variety of paleosol types, based on texture, fabric, color, and clay and pebble content. The relief on these erosional surfaces appears to decrease up-section from member A to the Picture Gorge Ignimbrite.
These erosional surfaces and their overlying beds represent cut-and-fill cycles which may correlate to world-wide changes in sea level and paleoclimate. During the late Eocene and early to mid Oligocene, these climatic-eustatic fluctuations spanned 2 to 4 my apiece and were of large magnitude.

Geological Society of American Annual Meeting, 1992.


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United States Department of the Interior, National Park Service