References
Reference
Workman Ford, Kerry (2006) Stratigraphic positions of marine reptile and dinosaur specimens in the Moreno Formation, in the Tumey Hills and Panoche Hills, Fresno County, California; New Mexico Museum of Natural History and Science Bulletin 35, , pp.407-41
Stratigraphic positions of marine reptile and dinosaur specimens in the Moreno Formation, in the Tumey Hills and Panoche Hills, Fresno County, California
Principal Author
Kerry Workman Ford
Header
Academic paper
Journal
New Mexico Museum of Natural History and Science Bulletin 35
Pages
407-411
Abstract
The Moreno Formation represents continuous deposition of marine sediments across the Cretaceous/ Tertiary (K/T) boundary. The formation is divided into four conformable members: Dosados, Tierra Loma, Marca and Dos Palos. The K/T boundary is placed within a 2.4-meter thick interval approximately 6.7 meters above the contact between the Marca Shale Member and the overlying Dos Palos Member. Forty marine reptile and dinosaur localities were measured to determine stratigraphic positions relative to the Cretaceous/Tertiary boundary. Most specimen localities are located in the Tierra Loma Member, approximately 75 meters stratigraphically below the K/T boundary. The highest fossil locality is that of a mosasaur and is located in the Marca Member, 7.5 meters below the Marca/Dos Palos contact, 14.2 meters below the K/T boundary. Based on an average sedimentation rate of 89.5m/my, this specimen occurs approximately 158,000 years before the K/T boundary. Further research is needed to determine why no specimens have been recovered nearer to the K/T boundary. Possibilities include taphonomic bias, lack of collecting specimens, and local extirpation of marine reptile populations.
Language
English