Recent advances in non-marine facies analysis of
siliciclastic systems have recognized the deposits of large fluvial systems
that exit upland catchment regions into fan-shaped accumulations. Here, Trendellet al. integrate sedimentologic, stratigraphic, paleopedologic,
geochronological and petrographic observations to assess the depositional processes
and forcing mechanisms of the Chinle Formation at Petrified Forest National
Park, USA. Upsection changes in grain size, channel width and depth, mineralogical
maturity, and character of paleosols are interpreted to represent deposition in
a progradational, large fan. Changing paleosol character is interpreted to
reflect progressively more upland deposits resulting from progradation, rather
than climate shifts. These results illustrate another large fan system, and
show how apparent shifts in climate can result from autogenic processes of fan
progradation.
Facies analysis of aprobable large-fluvial-fan depositional system:the Upper Triassic Chinle Formation at Petrified Forest National Park, Arizona,U.S.A. by Aislyn M. Trendell,
Stacy C. Atchley, and Lee C. Nordt
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