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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 980

Last Page: 980

Title: Paleobotany, Paleoenvironments, and Stratigraphy of Lower Kirtland Leaf Locality near Bisti, San Juan Basin, New Mexico: ABSTRACT

Author(s): Coleman Robison, Donald L. Wolberg, Adrian Hunt

Article Type: Meeting abstract


A new leaf locality has been discovered in Hunter Wash, near Bisti, in a sequence of mudstones, carbonaceous shales, siltstones, sandstones, and coal. The boundary between the Fruitland and Kirtland Formations is taken at the top of the highest carbonaceous shale above the highest Fruitland coal and below a prominent brown sandstone. The leaf locality lies within a 19-m measured section, about 4.3 m above the highest carbonaceous shale, within a gray-green shaly siltstone overlain by a sideritic concretionary lens. Poorly preserved bivalves and gastropods occur in the deposit, but leaves predominate.

Leaf collections contain the remains of ferns, conifers, and angiosperms; angiosperms dominate the assemblage. The most commonly found angiosperm genera found include Cercidiphyllum, Cissus, Ficus, Laurophyllum, Myrtophyllum, Lantanus, Salix, and Rhamnus. Study of the collection to date shows that most of the angiosperous leaves are of medium size with entire, or nearly entire margins and drip points. These features indicate a warm temperature to subtropical climate in the region during early Kirtland time.

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