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Abstract Detail

Campanian-Maastrichtian floras on Laramidia: vegetation trends west of the seaway

Wheeler, Elisabeth [1], Lehman, Tom [2].

Late Cretaceous Wood Assemblages of Big Bend National Park, Texas.

Campanian and Maastrichtian strata in the Aguja and Javelina formations of Big Bend preserve a well-documented succession of angiosperm and conifer wood types. Some of the angiosperm wood types appear to be unique to Big Bend (Agujoxylon and Gassonoxylon), while others (Sabinoxylon, Metcalfeoxylon, Baasoxylon, and Javelinoxylon) are known from correlative strata in nearby Mexico or New Mexico, but not elsewhere. Agujoxylon from the Aguja Formation has features suggesting affinities with the Olacaceae; Javelinoxylon from the Javelina Formation is Malvaceae. One striking functional trait of these angiosperms, especially Baasoxylon and Metcalfeoxylon, is their high incidence of parenchyma. Paralleling the distribution of the Big Bend angiosperms, araucarioid conifer wood types that occur in Big Bend have not been reported from correlative strata elsewhere, and the common cupressoid/podocarpoid woods here differ from the taxodioid woods common at northern localities. Most of the common angiosperm and conifer wood types in Big Bend represent large trees, and these must have been significant canopy-forming elements in southern paleolatitude forests. In-situ stump fields suggest that at least some of these forests had open woodland architecture, rather than closed canopy. Significant changes in wood types from Campanian through Maastrichtian time reflect in part a progression from coastal to inland environments, as well as the passage of time. These observations suggest that, in spite of the low latitudinal temperature gradient during Campanian-Maastrichtian time, forests in southern paleolatitudes of Laramidia differed significantly from those at northern paleolatitudes, at least in the dominant canopy-forming tree types, paralleling faunal differences.

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Related Links:

1 - DEPT OF WOOD & PAPER SCIENCE, 710 Dixie Trail, Raleigh, NC, 27607, USA
2 - Texas Tech University, Department of Geosciences, P.O. Box 4109, Lubbock, TX, 79409-1053, USA

secondary xylem
fossil wood.

Presentation Type: Colloquium Presentations
Session: CO3, Campanian-Maastrichtian floras on Laramidia: vegetation trends west of the seaway
Location: Sundance 3/Omni Hotel
Date: Wednesday, June 28th, 2017
Time: 11:00 AM
Number: CO3010
Abstract ID:93
Candidate for Awards:None

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