STRATI 2013 pp 1203-1206 | Cite as

Triassic Macrostratigraphy of the Western United States

  • David LovelaceEmail author
Conference paper
Part of the Springer Geology book series (SPRINGERGEOL)


The Triassic is an extraordinary time interval that experienced a Phanerozoic low in sedimentary packages, a major shift from carbonate to siliciclastic deposition, biotic recovery, the origination of the modern fauna, the peak of Pangaean accretion (and its initial break-up), and the end-Triassic extinction. However, quantification of the sedimentary record is necessary to more fully interrogate the nature of Triassic deposition. To better understand the factors that influenced the formation and preservation of the sedimentary record, this study describes the spatiotemporal distribution of sedimentary packages (and their properties) in the western US; this region preserves the most complete Triassic record in North America. The results demonstrate a significant climatic control on Early Triassic sediment accumulation, which is up to 4.5 times greater than that seen in the more tectonically controlled accumulation of Late Triassic sediment. It is demonstrated that global perturbations in δ13Ccarb closely match variability in the Early Triassic sedimentation rates, volume, and lithology. It is also during this interval that the highest turnover rate of sedimentary packages occurs. In contrast, the Late Triassic has much lower rates of sediment accumulation but greater lithological heterogeneity, including several intervals of coarse-grained sedimentation linked to the initiation of Andean-type subduction along the Cordilleran margin. Further results show that the distribution of sedimentary package duration throughout the Triassic interval is nearly identical to that reported for the entire Phanerozoic. This suggests that tectonic processes that govern package longevity in the Triassic of the western US are similar to those that govern larger-scale patterns across the continent. Quantification of the spatiotemporal distribution of Triassic sediments has provided a framework for comparing the structure of the sedimentary record across this dynamic interval. It is anticipated that this study will be the starting point for further investigations of attributes integral to the Triassic system, including improved studies of mass balance, interrogations of the Middle Triassic problem, and analyses of the preservation and distribution of body and trace fossils essential for understanding biotic recovery and the origins of the modern fauna.


Macrostratigraphy Triassic Modern fauna 


  1. Aswasereelert, W., Meyers, S. R., Carroll, A. R., Peters, S. E., Smith, M. E., & Feigl, K. L. (2013). Basin-scale cyclostratigraphy of the Green River formation. Wyoming Geological Society of America Bulletin,125(1–2), 216–228.CrossRefGoogle Scholar
  2. Beer, J. (2005). Sequence stratigraphy of fluvial and lacustrine deposits in the lower part of the Chinle Formation, south central Utah, United States: paleoclimatic and tectonic implications. PhD thesis University of Minnesota (unpublished), p. 180.Google Scholar
  3. Hannisdal, B., & Peters, S. E. (2010). On the relationship between Macrostratigraphy and Geological processes: Quantitative information capture and sampling robustness. The Journal of Geology,118(2), 111–130.CrossRefGoogle Scholar
  4. Heller, P. L., Dueker, K., & Mcmillan, M. E. (2003). Post-Paleozoic alluvial gravel transport as evidence of continental tilting in the U.S. Cordillera. Geological Society of America Bulletin,115(9), 1122–1132.CrossRefGoogle Scholar
  5. Lovelace, D. M. (2012). Triassic macrostratigraphy of the western United States and the ichnology, paleoecology, and paleoenvironments of the Early and Middle Triassic Chugwater Group, Wyoming. PhD thesis University of Wisconsin-Madison (unpublished), p. 190.Google Scholar
  6. Payne, J., & Kump, L. (2007). Evidence for recurrent Early Triassic massive volcanism from quantitative interpretation of carbon isotope fluctuations. Earth and Planetary Science Letters,256(1–2), 264–277.CrossRefGoogle Scholar
  7. Peters, S. E. (2006). Macrostratigraphy of North America. The Journal of Geology,114, 391–412.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of GeoscienceUniversity of Wisconsin–MadisonMadisonUSA

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