Silicified egg clusters from a Middle Cambrian Burgess Shale–type deposit, Guizhou, south China
- Jih-Pai Lin*1,
- Andrew C. Scott2,
- Chia-Wei Li3,
- Hung-Jen Wu3,
- William I. Ausich4,
- Yuan-Long Zhao5 and
- Yeu-Kuang Hwu6
- 1Department of Geological Sciences, The Ohio State University, Columbus, Ohio 43210, USA
- 2Geology Department, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK
- 3Institute of Molecular and Cellular Biology, College of Life Sciences, National Tsing Hwa University, Hsinchu, 300, Taiwan
- 4Department of Geological Sciences, The Ohio State University, Columbus, Ohio 43210, USA
- 5Institute of Resources and Environmental Sciences, Guizhou University, Guiyang, 550003, China
- 6Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
Abstract
Although knowledge of Cambrian fossil eggs and/or embryos has increased dramatically, embryos were previously unknown in siliciclastic settings of coeval strata. Here we report for the first time egg clusters in a fine-grained siliciclastic matrix from the Middle Cambrian Kaili Formation lagerstätte (513–501 Ma), south China. Some were imaged under synchrotron radiation. These spheroids are preferentially preserved as microcrystalline quartz and interpreted as marine invertebrate fossil eggs based on patterns of spheroid arrangement, shape, and analogues of fossil and modern invertebrate eggs. Embryos with cleavage cells are evident in at least one cluster. Detailed element analyses show that eggs are primarily preserved as solid silica replacement, and there is a calcite layer covering the eggs replacing the original organic layer. Silicification of intact invertebrate egg clusters is reported here as a new mode of preservation associated with a Burgess Shale–type deposit.
Footnotes
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↵*lin.542{at}osu.edu
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↵GSA Data Repository item 2006226, Figure DR1 (enlarged image of a four-cell embryo), Figure DR2 (enlarged image of an eight-cell embryo), and Figure DR3 (solubility diagram of silica and calcite in seawater), is available online at http://www.geosociety.org/pubs/ft2006.htm, or on request from editing{at}geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.
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- Accepted 14 July 2006.
- Received 17 May 2006.
- Revision received 13 July 2006.
- The Geological Society of America, Inc.
