Environmental Changes in the Tute Lake Basin, Siskiyou and Modoc Counties, California, from 3 to 2 Million Years Before Present U.S. GEOLOGICAL SURVEY BULLETIN 1933 AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey ,_along with prices of the last offerings, are given in the cur­ rent-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Sur­ vey publications released prior to the current year are listed in the most recent annual "Price and Availability List" Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated month­ ly, which is for sale in microfiche from the U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box 25425, Denver, CO 80225. Reports released through the NTIS may be obtained by writing to the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161; please include NTIS report number with inquiry. Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL Books OVER THE COUNTER Books Professional Papers, Bulletins, Water-Supply Papers, Techniques of Water-Resources Investigations, Circulars, publications of general in­ Books of the U.S. Geological Survey are available over the terest (such as leaflets, pamphlets, booklets), single copies of Earthquakes counter at the following Geological Survey Public Inquiries Offices, all & Volcanoes, Preliminary Determination of Epicenters, and some mis­ of which are authorized agents of the Superintendent of Documents: cellaneous reports, including some of the foregoing series that have gone out of print at the Superintendent of Documents, are obtainable by mail from • WASHINGTON, D.C.--Main Interior Bldg., 2600 corridor, 18th and C Sts., NW. U.S. Geological Survey, Books and Open-File Reports • DENVER, Colorado--Federal Bldg., Rm. 169, 1961 Stout St. Federal Center, Box 15425 • LOS ANGELES; California--Federal Bldg., Rm. 7638. 300 N. Denver, CO 80225 Los Angeles St. • MENLO PARK, California--Bldg. 3 (Stop 533). Rm. 3128, Subscriptions to periodicals (Earthquakes & Volcanoes and 345 Middlefield Rd. Preliminary Determination of Epicenters) can be obtained ONLY from • RESTON, Vlrglnla--503 National Center, Rm.lC402. 12201 the Sunrise Valley Dr. • SALT LAKE CITY, Utah--Federal Bldg .• Rm. 8105. 125 Superintendent of Documents South State St. Government Printing Omce • SAN FRANCISCO, California--Customhouse, Rm. 504, 555 Washington, D.C. 20402 Battery St. • SPOKANE, Washington--U.S. Courthouse, Rm. 678, West (Check or money order must be payable to Superintendent of Docu­ 920 Riverside Ave .. ments.) • ANCHORAGE, Alaska--Rm. 101, 4230 University Dr. • ANCHORAGE, Alaska--Federal Bldg, Rm. E-146, 701 C St. Maps For maps, address mail orders to U.S. Geological Survey, Map Distribution Maps Federal Center, Box 15286 Maps may be purchased over the counter at the U.S. Geologi­ Denver, CO 80215 cal Survey offices where books are sold (all addresses in above list) and at the following Geological Survey offices: Residents of Alaska may order maps from • ROLLA, Mlssourl--1400 Independence Rd. Alaska Distribution Secdon, U.S. Geological Survey, • DENVER, Colorado--Map Distribution, Bldg. 810, Federal New Federal Building - Box 12 Center 101 Twelfth Ave., Fairbanks, AK 99701 • FAIRBANKS, Alaska--New Federal Bldg., 101 Twelfth Ave. Environmental Changes in the Tule Lake Basin, Siskiyou and Modoc Counties, California, from 3 to 2 Million Years Before Present By DAVID P. ADAM, J. PLATT BRADBURY, HUGH J. RIECK, and ANDREI M. SARNA-WOJCICKI U.S. GEOLOGICAL SURVEY BULLETIN 1933 DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1990 For sale by the Books and Open-File Reports Section U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225 Library of Congress Cataloging-in-Publication Data Environmental changes in the Tule Lake basin, Siskiyou and Modoc Counties, California, from 3 to 2 million years before present I by David P. Adam ... [et al.]. p. cm.-(U.S. Geological Survey bulletin; 1933) Includes bibliographical references. Supt. of Docs. no.: I 19.3:1933 1. Paleoecology-California-Tulelake Region. 2. Paleobotany-Califor­ nia-Tulelake Region. 3.-Paleobotany-Piiocene. 4. Paleoclimatology-Cali­ fornia-Tulelake Region. I. Adam, David P. II. Series. QE75.89 no. 1933 557.3 s-dc20 90-3026 [QE720] [551.69794'21] CIP CONTENTS Abstract 1 Introduction 1 Site description 2 Methods 3 Results 3 Lithology 3 Dating 3 Biostratigraphy 3 Palynology 6 Diatoms 7 Discussion 11 Summary 11 References 12 FIGURES 1. Map showing Tulelake core site and vicinity 2 2. Graph of percentages of pine, TCI' (Taxodiaceae, Cupressaceae, and Taxaceae ), and Artemisia pollen plotted against depth for entire Tulelake section 4 3. Graph of selected variables plotted against depth and inferred age for the 3- to 2-Ma part of the Tulelake section 5 4. Graphs of percentages of pine pollen plotted against percentages of TCT pollen from Tulelake and Hodgdon Ranch, California 8 5. Graphs of percentages of pine pollen plotted against percentages of TCI' pollen from Clear Lake, California 9 6. Diagram of mean percentages of diatom groups in plankton and surfaee sediment of Upper Klamath Lake, Oregon 10 TABLE 1. Paleomagnetic horizons used for time control 6 Contents Ill Environmental Changes in the Tule Lake Basin, Siskiyou and Modoc Counties, California, from 3 to 2 Million Years Before Present By David P. Adam, J. Platt Bradbury, Hugh J. Rieck, and Andrei M. Sarna-Wojcicki Abstract This paper describes results of diatom and pollen analyses of sediment deposited during the interval from 3 Pollen and diatom analyses of a core from the town of to 2 Ma at what is now the town of Tulelake, Siskiyou Tulelake, Siskiyou County, California, for the period between County, California (fig. 1). The town lies within the bed 3 and 2 Ma reveal a paleoclimatic and paleolimnologic of ancient Tule Lake, now largely reclaimed for agricul­ sequence recording a long, warm time interval that lasted ture. Diatoms and pollen grains are well preserved and from about 2.9 to 2.6 Ma and had a short, cooler interval within it. During this warm interval, the regional vegetation abundant in sediments cored from the ancient lake bed, surrounding ancient Tule Lake was a mixed coniferous and their biostratigraphy documents limnological and forest, and Tule Lake was a warm monomictic lake. Approx­ environmental changes in this region for the last 3 million imate modern analogs for this Pliocene fossil record at years. The interval between 3 and 2 Ma is of special Tulelake are found at least 2 degrees farther south. The interest because significant climatic changes during that Tulelake warm interval appears to have correlatives in the interval have been inferred from the foraminiferal and North Atlantic oxygen isotope record and in the pollen record oxygen isotope stratigraphy of marine cores (Loubere of the Reuverian in the Netherlands. An interval beginning at and Moss, 1986). Specifically, o180 values of s3.5 per about 2.4 Ma was characterized at Tule Lake by slow mil characterize the marine record earlier than about 2.4 sedimentation, by changes in the relative amounts of algae in Ma, and these are interpreted to represent reduced the lake, and by an increase in the maximum percentages of extent of continental ice and consequently higher sea Artemisia pollen. levels and generally warmer temperatures (Ruddiman and Raymo, 1988). Warmer climates in the future may INTRODUCTION be a result of the current increase in atmospheric C02 The upper Klamath River drainage basin, in north­ released by the burning of fossil fuels. Late Pliocene ernmost California and south-central Oregon, is physio­ warm climates may be relevant analogs for a C02 - graphically part of the Basin and Range province. Several enhanced world, and hence it is important to document factors make it well suited for paleoclimatic and paleo­ their characteristics. limnologic studies: A number of modern and older· The biostratigraphy of the Tulelake core provides depositional basins within this region contain thick sedi­ an opportunity for such documentation. This core, dated mentary sequences that span much of the Quaternary by paleomagnetic reversals and tephrochronology and perhaps reach well back into the late Cenozoic. The (Adam and others, 1989), includes a continuous lacus­ present climate is less arid than in the Great Basin trine stratigraphic record between 3 and 2 Ma. Changes proper, and modern lakes in many of these depositional in the relative abundance of pine pollen versus pollen of the Taxodiaceae, Cupressaceae, and Taxaceae (TCf) basins provide habitats suitable for environmentally sen­ 1 sitive organisms such as ostracodes and diatoms as well group reflect changes in the composition of the regional as depositional environments suitable for the preserva­ forest through time; proportional shifts between plank­ tion of pollen. Numerous tephra layers, mostly from the tonic diatoms (Aulacoseira so/ida and large species of volcanoes of the southern Cascades, can be used to correlate both between basins and with sequences in 1 more distant areas. Pollen grains of genera and species within the TCT group cannot be reliably distinguished in most cases, so they are lumped in a group for this study. Species that are particularly relevant to the interpretation of the Tulelake core include Juniperus occidentalis Manuscript approved for publication, Februaty 6, 1990.