Abstract Detail

Paleobotanical Section

DeVore, Melanie L. [1], Kenrick, Paul [2], Pigg, Kathleen B. [3], Ketcham, Richard A. [4].

CT-scanning the London Clay: an excellent noninvasive technique for studying pyritized fossil fruits.

Pyritized fossil plants from the Eocene London Clay flora have been collected for nearly 300 years and over 500 plant types and 350 named species are known from the flora. Unfortunately, pyrite decay is a significant danger to London Clay specimens and many inadequately protected specimens from early collections have been destroyed. Conservation of material is a high curatorial priority and careful measures are taken at the Natural History Museum, London, to prevent the thousands of specimens in the collection from being exposed to high relative humidity and oxidizing conditions. The current method of choice for preserving these invaluable specimens is to immerse them in tubes of silicone oil. The London Clay fruits have proven to be excellent candidates for detailed 3-dimensional study using the nondestructive techniques of X-ray Computed Tomography (CT scanning). In collaboration with the High Resolution X-ray CT Facility, University of Texas at Austin (UTCT), we recently examined specimens of two London Clay fruit types Palaeorhodomyrtus (Myrtaceae) and Toona (Meliaceae). Images captured using CT scanning clearly elucidate the 3-dimensional organization of fruit tissues in both fruits as well as the seeds they contain. The specimens can be studied directly in their vials of silicone oil, as the silicone oil fills spaces within specimens and provides the necessary contrasting boundaries detected by CT imaging. The silicon oil also acts as a calibration baseline ("wedge") and aids in the imaging process. Further studies of fruits and seeds from the London Clay using nondestructive CT methodology will help resolve the relationships of forms of uncertain taxonomic affinities and will provide a means of examining type material and other critical specimens without removing them from silicon oil and increasing the risk of chemical and physical damage.

1 - Georgia College & State University, Biological & Environmental Sciences, 135 Herty Hall, Campus Box 81, Milledgeville, Georgia, 31061, USA
2 - Natural History Museum, Paleontology Department, Cromwell Road, London, SW7 5BD, United Kingdom
3 - Arizona State University, School of Life Sciences, Asu, Main Campus, Po Box 874501, Tempe, Arizona, 85287-4501, USA
4 - University of Texas at Austin, Jackson School of Geosciences, Manager, High-Resolution X-Ray Computed Tomography Facility, 1 University Station, C-1100, Austin, Texas, 78712-0254, USA

Keywords:
CT Scan
London Clay
Fossil Fruit
Preservation.

Presentation Type: Oral Paper
Session: 32-5
Location: Salon G - Austin Grand Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 11:15 AM
Abstract ID:122