Abstract Detail

Paleobotanical Section

Leng, Qin [1], Wang, Li [2].

Improved paleobotanical techniques enhance the application of thin cuticle of Metasequoia fossils as a paleoclimatic proxy.

With a continuous and widely distributed fossil record dated back to the Late Cretaceous in the Northern Hemisphere, and even more importantly, with a representative species (Metasequoia glyptostroboides) still living in its native land in South-central China, Metasequoia, a cupressaceous (formerly taxodiaceous) genus has long been used as an effective paleoclimatic proxy for the past 100 million years of Earth history. A recent survey of its native population discovered that an individual tree in Paomu Village possesses morphological and anatomical characters that are different from the rest of the living population but remarkably identical to fossils. These ancestral characters displayed in a living tree show great potential for a more precise paleoclimatic reconstruction. More techniques are applied to quantitatively reconstruct paleoclimatic parameters including the Stomatal Frequency (SF, including SD-Stomatal Density, SI-Stomatal Index, and SNL-Stomatal Number per (conifer needle) Length) analysis for atmospheric carbon dioxide (CO₂) concentration reconstruction. Precise SF calculation can be made on clean cuticular membranes with sufficient sizes. However, as Metasequoia is a deciduous conifer with thin cuticles, it has been difficult to obtain cleaned cuticles, particularly of the lower epidermis, with sufficient size for SF calculation from Metasequoia leaf fossils. Here we present two improved techniques, i.e., the combined epidermis stripping and cuticle isolation technique and the cuticle nail polish “strengthening” technique, that allow us to successfully obtain lower cuticular membranes which are large enough for SF calculation from Paleocene, Eocene, and Miocene Metasequoia fossil leaves. At the same time these fossil cuticular membranes can still be used for other paleobotanical purposes, e.g., ultra-morphological observation under SEM. (Supported by CAS/SAFEA International Partnership Program for Creative Research Teams, the Major Basic Research Projects (2006CB806400), and the National Science Foundation of China.)

Broader Impacts:

1 - Bryant University, Science and Technology, College of Arts and Sciences, 1150 Douglas Pike, Smithfield, RI, 02917, USA
2 - Graduate School of the Chinese Academy of Sciences, Beijing, 100049, China

Keywords:
Metasequoia
paleoclimate
cuticle.

Presentation Type: Oral Paper:Papers for Sections
Session: 54
Location: 556A/Convention Center
Date: Wednesday, August 4th, 2010
Time: 11:15 AM
Number: 54004
Abstract ID:481