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    This chapter has been cited by the following publications. This list is generated based on data provided by CrossRef.

    Sei, Makiri Robinson, David G Geneva, Anthony J and Rosenberg, Gary 2017. Doubled helix: Sagdoidea is the overlooked sister group of Helicoidea (Mollusca: Gastropoda: Pulmonata). Biological Journal of the Linnean Society, Vol. 122, Issue. 4, p. 697.

    Stocker, Michelle R. and Kirk, E. Christopher 2016. The first amphisbaenians from Texas, with notes on other squamates from the middle Eocene Purple Bench locality. Journal of Vertebrate Paleontology, Vol. 36, Issue. 3, p. e1094081.

    Tomiya, Susumu and Tseng, Zhijie Jack 2016. Whence the beardogs? Reappraisal of the Middle to Late Eocene ‘Miacis’ from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora). Royal Society Open Science, Vol. 3, Issue. 10, p. 160518.

    Campisano, Christopher J. Kirk, E. Christopher Townsend, K. E. Beth Deino, Alan L. and Farke, Andrew A. 2014. Geochronological and Taxonomic Revisions of the Middle Eocene Whistler Squat Quarry (Devil’s Graveyard Formation, Texas) and Implications for the Early Uintan in Trans-Pecos Texas. PLoS ONE, Vol. 9, Issue. 7, p. e101516.

  • Print publication year: 1996
  • Online publication date: July 2010

9 - Magnetostratigraphy of the Eocene-Oligocene transition in Trans-Pecos Texas



Previous studies of the Uintan, Duchesnean, and Chadronian rocks and their mammalian faunas of Trans-Pecos Texas are supplemented by more recent magnetostratigraphic research to provide a more up-to-date chronostratigraphic framework. In the Vieja area, reinter-pretations of the work of Testarmata (1978; Testarmata and Gose, 1979), plus new magnetics, show that the Vieja Group (Colmena Chambers-Capote Mountain Tuffs) spans the interval from Chron C19r (42 Ma) to C13n (33 Ma). The early Duchesnean Candelaria l.f. occurs in Chron C19n (about 41.5 Ma), the late Duchesnean Porvenir l.f. and early Chadronian Little Egypt l.f. in Chron C17n (37-38 Ma), and the mid-Chadronian Airstrip l.f. in C16n (35.5 Ma). In the Agua Fria area, the Devil's Graveyard Formation spans the interval from C21n (46.5 Ma) to C13n (33 Ma), with a gap between C16n (35.5 Ma) and C18n (39 Ma) (wherein lie the Duchesnean faunas of the Skyline and Cotter channels). Revisions of Walton's (1992) magnetic interpretations place the late Bridgerian Junction l.f. in C21n (46.5 Ma), the early Uintan Whistler Squat l.f. in early C20r (45-46 Ma), the late Uintan Serendipity and Purple Bench l.f. in C19r (42 Ma) and C18r (41 Ma), respectively. The mid-Chadronian Coffee Cup l.f. occurs in Chron C15r (about 35 Ma).


The Trans-Pecos region of Texas is the only place in North America where the middle-late Eocene is recorded by superposed mammalian faunas datable by both radiometrics and magnetic stratigraphy.

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The Terrestrial Eocene-Oligocene Transition in North America
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