scholarly journals Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America

Author(s):  
Denver W Fowler

Interbasinal stratigraphic correlation provides the foundation for all consequent continental-scale geological and paleontological analyses. Correlation requires synthesis of lithostratigraphic, biostratigraphic and geochronologic data, and must be periodically updated to accord with advances in dating techniques, changing standards for radiometric dates, new stratigraphic concepts, hypotheses, fossil specimens, and field data. Outdated or incorrect correlation exposes geological and paleontological analyses to potential error. The current work presents a high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. 40Ar / 39Ar radiometric dates are newly recalibrated to both current standard and decay constant pairings. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina Formations, Texas, and recalibration corrections in particular affect the relative age positions of the Belly River Group, Alberta; Judith River Formation, Montana; Kaiparowits Formation, Utah; and Fruitland and Kirtland formations, New Mexico. The stratigraphic ranges of selected clades of dinosaur species are plotted on the chronostratigraphic framework, with some clades comprising short-duration species that do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern that is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. The recent hypothesis of intracontinental latitudinal provinciality of dinosaurs is shown to be affected by previous stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may be useful for high resolution biostratigraphy.

2017 ◽  
Author(s):  
Denver W Fowler

Interbasinal stratigraphic correlation provides the foundation for all consequent continental-scale geological and paleontological analyses. Correlation requires synthesis of lithostratigraphic, biostratigraphic and geochronologic data, and must be periodically updated to accord with advances in dating techniques, changing standards for radiometric dates, new stratigraphic concepts, hypotheses, fossil specimens, and field data. Outdated or incorrect correlation exposes geological and paleontological analyses to potential error. The current work presents a high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. 40Ar / 39Ar radiometric dates are newly recalibrated to both current standard and decay constant pairings. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina Formations, Texas, and recalibration corrections in particular affect the relative age positions of the Belly River Group, Alberta; Judith River Formation, Montana; Kaiparowits Formation, Utah; and Fruitland and Kirtland formations, New Mexico. The stratigraphic ranges of selected clades of dinosaur species are plotted on the chronostratigraphic framework, with some clades comprising short-duration species that do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern that is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. The recent hypothesis of intracontinental latitudinal provinciality of dinosaurs is shown to be affected by previous stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may be useful for high resolution biostratigraphy.


2016 ◽  
Author(s):  
Denver W Fowler

Late Cretaceous deposits of the North American Western Interior represent the best, if not only, opportunity to construct a high-resolution chronostratigraphic framework within which to conduct continental-scale geological and paleontological analyses. This is due to the serendipitous combination of large areas of outcrop, interfingering marine units with biostratigraphically informative fossils, and a consistent scattering of radiometric dates due to synorogenic volcanic activity. Accurate correlation is essential for testing a large number of current geological and paleobiological hypotheses; however, despite the large amount of data available, many published correlations suffer from inaccuracies or are simply based on outdated information. Here I present a comprehensive high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. For the first time, nearly two hundred 40Ar / 39Ar radiometric dates are recalibrated to both current standard and decay constant pairings, correcting errors in previous recalibrations. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina Formations, Texas, and miscalculations in recently published analyses are corrected which in particular affects the relative age positions of the Belly River Group, Alberta; Judith River Group, Montana, Kaiparowits Formation, Utah, and Fruitland and Kirtland Formations, New Mexico. This work represents the most extensive and accurate interbasinal correlation currently available for the North American Western Interior and should replace all previously published similar works and diagrams. The stratigraphic ranges of selected dinosaur clades are plotted on the chronostratigraphic framework, typically forming stacks of short-duration species which do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern which is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. Purported north-south provinciality of dinosaurs is shown to be mostly an artifact of stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may represent the highest resolution biostratigraphic markers to be used where radiometric dates are not available.


Zootaxa ◽  
2020 ◽  
Vol 4782 (1) ◽  
pp. 1-115 ◽  
Author(s):  
CHRISTOPHER L. GARVIE ◽  
JAMES L. GOEDERT ◽  
ARIE W. JANSSEN

A comprehensive discussion and survey is made of all North American Paleogene and Late Cretaceous pteropods, and their systematics reviewed. From the West Coast of North America pteropod fossils have been collected from 23 localities in Washington State, and from the Gulf Coastal Plain they have been found in 40 localities. We also review earlier published specimens from boreholes in the Atlantic Coastal Plain. As a result, six new species are introduced from the Gulf Coast (Currylimacina asperita Garvie sp. nov., Heliconoides hodgkinsoni Garvie sp. nov., Limacina texanopsis Garvie sp. nov., Limacina parvabrazensis Garvie & Janssen sp. nov., Limacina pseudopygmaea Garvie & Janssen sp. nov., Cheilospicata cedrus Garvie sp. nov.) and one from Washington State (Clio gailae Goedert & Janssen sp. nov.). The geographical distribution and/or stratigraphic ranges of several species has been extended, for example, Limacina canadaensis Hodgkinson, 1992, is reported for the first time from western North America. Some species originally described from elsewhere, Altaspiratella multispira (Curry, 1982), Heliconoides bartonensis (Curry, 1965), L. karasawai Ando, 2011, L. aff. valvatina (Reuss, 1867), Creseis spina (Reuss, 1867) and Clio chadumica Korobkov, 1966, are reported for the first time from the Americas. New specimens of several poorly known species yielded additional information on morphology or biostratigraphy. It is shown that some species have longer temporal ranges in America, occurring in, or continuing into younger deposits than those in Europe. In addition to the only Cretaceous pteropod from Washington State known so far, several enigmatic species possibly representing Pteropoda are described from the Late Cretaceous (Maastrichtian) and Danian of Texas, which allows a salient discussion on the early history of Pteropoda. An enigmatic specimen from the Eocene of Texas might represent a very early form of Gymnosomata. This analysis shows that there may be more pteropod species represented during the Late Cretaceous and Paleocene than previously suspected. 


2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira

2020 ◽  
Author(s):  
Natalie Sorrem ◽  
◽  
Clara L. Meier ◽  
Gabriel J. Bowen ◽  
Brady Z. Foreman ◽  
...  

2013 ◽  
Vol 339 ◽  
pp. 728-731 ◽  
Author(s):  
Cun Lei Li ◽  
Lei Qin ◽  
Xue Li ◽  
Xi Long Zhang

With the instruction of the high resolution sequence stratigraphy and sedimentology theory, and the comprehensive application of 11 wells core, more than 800 mud logging and log data, high resolution sequence stratigraphic characteristics research in the XII Group of the Member III of Qing Shankou Formation in the Qianan oilfield has been finished. The results show that the study area can be divided into one middle-term base level cycle and five short-term base level cycles. The only sequence structure of middle term cycle is (B type) and the short term cycle mainly consists of B types meanwhile there are small mounts of upward deepening structures (A type) and symmetric structures (C type). Based on the classification of base-level cycles, fine stratigraphic correlation is conducted by using isochronous cycle correlations. In addition, 15 high resolution sequence stratigraphic frameworks are established which unify the study area and provide the solid geological basis for the sandstone distribution, the identification of mainly oil-bearing sand bodies and potential oil reservoirs.


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