Concepts of Sequence Stratigraphy, with Examples from Strata of Late Proterozoic and Cambrian Age in the Western United States

  1. Nicholas Christie-Blick,
  2. Marjorie Levy,
  3. Jeffrey F. Mount,
  4. Philip W. Signor and
  5. Paul Karl Link
  1. Nicholas Christie-Blick and
  2. Marjorie Levy

Published Online: 17 MAR 2013

DOI: 10.1029/FT331p0023

Late Proterozoic and Cambrian Tectonics, Sedimentation, and Record of Metazoan Radiation in the Western United States: Pocatello, Idaho, to Reno, Nevada 20-29 July, 1989

Late Proterozoic and Cambrian Tectonics, Sedimentation, and Record of Metazoan Radiation in the Western United States: Pocatello, Idaho, to Reno, Nevada 20-29 July, 1989

How to Cite

Christie-Blick, N., Levy, M., Mount, J. F., Signor, P. W. and Link, P. K. (1989) Concepts of Sequence Stratigraphy, with Examples from Strata of Late Proterozoic and Cambrian Age in the Western United States, in Late Proterozoic and Cambrian Tectonics, Sedimentation, and Record of Metazoan Radiation in the Western United States: Pocatello, Idaho, to Reno, Nevada 20-29 July, 1989, American Geophysical Union, Washington, D. C.. doi: 10.1029/FT331p0023

Author Information

  1. Department of Geological Sciences and Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964

Publication History

  1. Published Online: 17 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875906577

Online ISBN: 9781118667415

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Keywords:

  • Highstand systems tract (HST);
  • Huntsville;
  • Maple Canyon and Inkom Formation;
  • Sequence stratigraphy;
  • Sheeprock Mountains

Summary

Sequence stratigraphy is a method of studying repetitively arranged sedimentary facies in the context of their stratal geometry. The key to sequence stratigraphy is the recognition of unconformity-bounded depositional sequences, which represent the fundamental building blocks of sedimentary successions. Most sequence boundaries have time-stratigraphic significance in that with few exceptions strata overlying an unconfonnity are everywhere younger than strata underlying it. Sequence stratigraphy therefore offers a way of achieving intrabasinal time correlation, and is of considerable importance for basin analysis in Proterozoic rocks. Regional sequence boundaries form primarily in response to variations in the rate of sea-level change and rate of subsidence, though these controls are difficult to distinguish in Proterozoic examples.

The timing of transgressions and regressions is systematically out of phase with respect to associated sequence boundaries. This allows the recognition within any sequence of three systems tracts (lithofacies assemblages) on the basis of stratigraphic position, stratal geometry and facies arrangements. The oldest deposits within a sequence compose the lowstand and shelf-margin systems tracts, depending on whether they overlie a type 1 or type 2 sequence boundary, respectively. The upper boundary of both systems tracts is the transgressive surface, which represents the time of maximum regression. The transgressive systems tract overlies the transgressive surface and is bounded above by the surface of maximum flooding, which in deeper-water facies corresponds with a relatively thin interval of sediment starvation. The surface of maximum flooding is overlain by the highstand systems tract, which is bounded above by the next sequence boundary. Sequence boundaries, transgressive surfaces, other marine flooding surfaces and marine hardgrounds (associated with sediment starvation) may all appear as prominent contacts in outcrop, though they differ in detail and sedimentological significance.

Sequence stratigraphic concepts have been used to interpret rocks of Late Proterozoic and Cambrian age in the western United States. Most of our work has been concentrated in Utah and Idaho, but we include the results of reconnaissance studies in Nevada and California. A section at Huntsville, Utah, and a regional cross section for one sequence boundary (in the upper part of the Caddy Canyon Quartzite) illustrate the methodology. The Huntsville succession has been divided into five unconformity-bounded depositional sequences. The most prominent sequence boundaries are within the Caddy Canyon Quartzite and at the base of the Mutual Formation. A third boundary, at the base of the Geertsen Canyon Quartzite may be traced into adjacent Idaho. A fourth sequence boundary, tentatively identified in the upper part of the Maple Canyon Formation, can be recognized only locally. Prominent marine flooding surfaces, probably within transgressive systems tracts, are identified at the base of the Kelley Canyon Formation and at the base of the Inkom Fonnation. The latter contact is probably faulted at Huntsville. Lenses of concretionary argillaceous limestone in the lower part of the Kelley Canyon Formation may represent a starvation interval. Starvation intervals are not present in most of the sequences because the sediments accumulated mainly in nearshore and fluvial environments.

The sequence boundary located at or near the top of the Caddy Canyon Quartzite is demonstrably of regional extent, and can be traced through lateral facies changes from fluvial (Portneuf Range, Idaho, and Huntsville) to marine environments (Sheeprock Mountains and Dugway Range, Utah, and Egan Range, Nevada). As much as several tens of metres of erosional relief has been documented in both the Sheeprock Mountains and Dugway Range. In both these localities, the sequence boundary is overlain by disorganized conglomerate, interpreted as the product of debris flow and assigned to the lowstand systems tract. Quartzite and conglomerate in unit F of the McCoy Creek Group (Egan Range) is tentatively interpreted as the lowstand prograding wedge of the same sequence.