Introduction

Ordovician from the Andes, edited by Guillermo L. Albanesi, Matilde S. Beresi, and Silvio H. Peralta, is the eighth volume of contributions produced by international symposia on the Ordovician System. I am pleased that it continues a long-standing tradition. The volumes produced since the first international meeting on the Ordovician System in 1971 present a wealth of information on all aspects of the Ordovician System worldwide. They, together with the associated symposia, are as follows:

Babin, C., 1971, Colloque Ordovicien-Silurien, Breste, Septembre 1971: Memoires du Bureau de recherches geologiques et minieres, v. 73, 462 pp. "First Ordovician Symposium", University of West Brittany, Brest, France, September 1971.

Bassett, M.G., ed., 1976, The Ordovician System: Proceedings of a Palaeontological Association Symposium, Birmingham, 18-20 September 1974, University of Wales Press and the National Museum of Wales, Cardiff, 696 pp. Second International Symposium on the Ordovician System, University of Birmingham, England, September 1974.

Third International Symposium on the Ordovician System, The Ohio State University, Columbus, Ohio, USA, 1977; no volume

Bruton, D.L., ed., 1984, Aspects of the Ordovician System, Palaeontological Contributions from the University of Oslo, NO. 295, 228 pp., Selected papers from the Fourth International Symposium on the Ordovician System, Oslo, Norway, August 1982,.

Barnes, C.R., and Williams, S.H., eds., 1991, Advances in Ordovician Geology, Geological Survey of Canada paper 90-9, 336 pp.; Selected papers from the Fifth International Symposium on the Ordovician System, Memorial University of Newfoundland, St. Johnís, Canada, August 1988.

Webby, B.D., and Laurie, J.R., eds., 1992, Global Perspectives on Ordovician Geology, A.A. Balkema/Rotterdam/Brookfield, 513 pp.; Proceedings of the Sixth International Symposium on the Ordovician System, University of Sydney, Australia, 15-19 July 1991.

Cooper, J.D., Droser, M.L., and Finney, S.C., eds., 1995, Ordovician Odyssey, Pacific Section of Sedimentary Geology (SEPM), Fullerton, CA, Book Nļ 77, 498 pp., Short Papers (proceedings) for the Seventh International Symposium on the Ordovician System, University of Nevada, Las Vegas, Nevada, USA June 12-16, 1995.

Kraft, P., and Fatka, O., eds., 1999, Quo vadis Ordovician?, Acta Universitatis Carolinae Geologica, v. 43, no. 1/2, 534 pp., Short papers (proceedings) for the Eighth International Symposium on the Ordovician System, Charles University, Prague, Czech Republic, June 20-25, 1999.

Some of these are volumes of selected papers compiled after the meeting. Others include all keynote papers presented at the meeting. Since the 1995 meeting in Las Vegas, the volumes are proceedings that include short papers of all presentations at the meeting, and they are published before, and distributed at, the meeting. All eight volumes highlight current research, and all provide ready access to Ordovician issues for the uninitiated. Contributions to the volumes vary greatly from global and regional analyses to local investigations, from compilations to exciting new research results. All aspects of Ordovician geology have been treated, primarily stratigraphy, biostratigraphy, paleontology, and paleobiology, but also volcanism, eustasy, orogenesis, tectonics, paleoclimatology, sea-water geochemistry, and geochronology. Much of the information presented results from traditional geological investigations, but use of modern technologies and new methodologies are incorporated in many of the contributions. Many of the contributions in each volume, as with the presentations at the associated symposia, reflect the "hot topics" current at the time, e.g. the Argentine Precordillera at the Las Vegas meeting in 1995 and biodiversity at the Prague meeting in 1999, and chronostratigraphic boundaries under consideration by the Subcommission on Ordovician Stratigraphy. The volumes also reflect the participants and location of the meeting.

Ordovician from the Andes is the proceedings volume for the 9th International Symposium on the Ordovician System, held in San Juan, Argentina, 18-21 August 2003. The location allows for the participation of many Argentinean colleagues, which is reflected in the contributions to the proceedings volume, and which is a goal of the Ordovician Subcommission. The Subcommission on Ordovician Stratigraphy of the International Commission on Stratigraphy (IUGS) was formally organized in 1974 at the Second International Symposium on the Ordovician System at Birmingham, England. Since then, it has been the Ordovician Subcommission that approves the sites and sponsors the international symposia. Four have been held in Europe (Brest, Birmingham, Oslo, Prague), three in North America (Columbus, St. Johnís, Las Vegas), and one in Australia (Sydney). The San Juan symposium is the first in South America. Each of these venues is within proximity to outstanding Ordovician geology. Exposure to the local geology through symposium presentations and during associated field excursions allows visiting participants to greatly expand their knowledge of Ordovician stratigraphy, which is critical for understanding global Ordovician issues. The international symposia are also the venue for much of the formal business of the ICS Subcommission on the Ordovician Stratigraphy. Its major task is definition of global chronostratigraphic subdivisions (series and stages) for the Ordovician System by selection of Global Standard Stratotype Sections and Points (GSSPs) that define the lower boundaries of the subdivisions. Currently two remain to be selected - the base of the Middle Ordovician Series and the base of the upper stage of the Upper Ordovician Series. Therefore, the topics receiving the greatest attention in Ordovician from the Andes are the spectacular Ordovician stratigraphy, paleontology, and associated geology of Argentina and Bolivia and the boundaries between the Lower and Middle Ordovician Series and at the base of the uppermost stage of the Ordovician.

The 9th ISOS in San Juan is a joint meeting with the 7th International Graptolite Conference and the 2003 Field Meeting of the Subcommission on Silurian Stratigraphy. Thus, it is attractive to an unusually wide audience of participants many of whom have interests across the spectrum of the three organizations. Accordingly, Ordovician from the Andes is an eclectic volume with much to offer. It includes 94 papers on Ordovician topics, 17 papers on graptolites of which 13 treat Ordovician graptolites, and 13 on Silurian matters with 4 addressing the Ordovician/Silurian boundary. Of 124 papers in the volume, 44 are based on rocks and fossils in Argentina and Bolivia. Yet, in spite of this concentration, geographic coverage in this volume includes Canada, USA, Greenland, Austria, Britain, Norway, Sweden, Spain, Portugal, France, Germany, Czech Republic, Estonia, Bulgaria, Poland, Russia, Turkey, Libya, Morocco, Kazakhstan, Mongolia, China, Korea, and Australia. Biostratigraphy is the subject of 29 papers of which 8 discuss the GSSP for the base of the Middle Ordovician Series. Although graptolites and conodonts are the subject of most biostratigraphic papers, important new studies of acritarch and chitinozoan biostratigraphy are also presented. Paleontology/paleobiology is the focus of 25 papers; 21 are devoted to sedimentology and basin analysis; 11 to paleogeography, and 9 to geochemistry, magmatism, K/bentonites and geochronology. Additional important topics include eustasy, chemostratigraphy, paleooceanography and climate modeling. Ordovician from the Andes thus not only sustains the long tradition of symposia volumes it also maintains a high standard of scientific value and currency, and represents the vitality of Ordovician research.