Friedman, Virginia , Lambert, Joseph B. , Nguyen, Truongan V. .
Late Cretaceous amber in Texas: A preliminary study.
Fossil resin (amber) is reported in abundance from a new amberiferous locality in North Central Texas. The amber was found at the stratigraphic level of the non-marine Dexter member of the lower Woodbine Formation. The amber pieces are found as clasts in thin carbonaceous horizons and are present in different sizes from sand grain size up to 3 cm in length. Some of the amber clasts have the appearance of a hickory nut when found unbroken. The clasts break relatively easily in a conchoidal fashion exhibiting a variety of colors from pale yellow, dark yellow, reddish brown and white opaque. The exterior, if present, is a brownish oxidized rough surface. The interior of the amber clasts is for the most part, transparent or translucent and glistening. So far no definitive zooinclusions have been found but some clasts present abundant plant debris inside as well as bubbles of different sizes and shapes. Solid-state 13C NMR as well as solution 1H NMR spectroscopic analysis were carried out on selected amber samples and based on their spectral characteristics are assigned to the Group A of the Lambert, et al 2008 classification and as such the botanical origin is most likely a conifer. This is further suggested by palynological analysis carried out on the sediments of the outcrop that indicate the presence of abundant conifer pollen, fern spores, and very rare dinoflagellates. The low diversity but well preserved palynomorph assemblage is suggestive of a nearby source for the paleoflora present composed mainly of conifers and ferns. The kerogen composition is characteristic of a fluvial system. The environment of deposition is interpreted as non-marine, fluvial deltaic with abundant siltstones, mudstones and rare horizons of carbonaceous (sub- bituminous) clays where the amber is mostly located. The sediment where the amber is found is composed of abundant charcoal particles. This may in concordance with the Cretaceous period being described as a time of fires. The age of the sediments based on stratigraphic data and palynomorph assemblage is mid-Cenomanian. This locality represents an important contribution to the paleobotany of this area inasmuch as it is the first study of amber in Texas.
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1 - 1000 Walnut Place, Mansfield, TX, 76063, USA
2 - Trinity University, Chemistry, One Trinity Place, San Antonio, TX, 78212-7200, USA
Presentation Type: Poster This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
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