The Oxford Lake-Level Data Bank: Readme File, Appendices A and B ----------------------------------------------------------------------- World Data Service for Paleoclimatology ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! CONTRIBUTORS: COHMAP members IGBP PAGES/WDCA Data Contribution Series #: 94-028 NAME OF DATA SET: The Oxford Lake-Level Data Bank LAST UPDATES: 10/1994 (Original Receipt by WDC-A Paleo) 12/1994 (Correction to lakelevindex.txt; see note in that file dated 3/95) 8/2022 (Correction to file names and URLs in readme_oxford-lldb.txt; addition of dataset DOI and headers to lakeres.txt, lakedata.txt, lakelevindex.txt, numrefs.txt, and pubindex.txt; addition of NOAA template files oxford_lldb_levels-noaa.txt and oxfort_lldb_14C-noaa.txt containing Lake Stand Info and Dating Info, respectively, in tab-delimited format) GEOGRAPHIC REGION: Global PERIOD OF RECORD: 0-20,000 YBP LIST OF FILES: The following files contain the following information: 1. lakeres.txt Lake Stand and Dating Info, with descriptive headers 2. lakedata.txt Lake Stand and Dating Info, without headers 3. lakelevlindex.txt Appendix C: Site information for all lakes 4. numrefs.txt Appendix E: publication reference list 5. pubindex.txt Appendix D: list of BMN and corresponding publication number 6. readme_oxford-lldb.txt Appendix A and B: Methodology and description of data format 7. oxford_lldb_levels-noaa.txt NOAA Template File of Lake Stand Info from lakeres.txt and lakedata.txt 8. oxford_lldb_14C-noaa.txt NOAA Template File of Dating Info from lakeres.txt and lakedata.txt All metadata and data for this study can be accessed via: https://doi.org/10.25921/mxae-9596 ORIGINAL REFERENCE: Street-Perrott, F.A., D.S. Marchand, N. Roberts, and S.P Harrison, 1989. Global Lake-Level Variations from 18,000 to 0 Years Ago: A Paleoclimatic Analysis. U.S. Department of Energy Technical Report 46, Washington, D.C. 20545. Distributed by National Technical Information Service, Springfield, VA 22161. DESCRIPTION: APPENDIX A. CRITERIA USED TO DETERMINE LAKE STATUS AND DATING CONTROL. Lake Status Lake status was originally determined at 1000-year intervals between 30 ka BP and the present day (0 ka BP = 1950 AD), although only the data sets for 3000-year intervals since 18 ka BP are presented here. The sampling scheme used in this report has the effect of suppressing shorter-term variations, which tend to reflect regional climatic and hydrological perturbations, and emphasizing longer-term global variations. A standardization procedure was applied in order to render all basins comparable, regardless of size. The total range of fluctuation experienced by each basin during the past 30,000 years was divided into three lake-status categories with a similar overall frequency of occurrence in the data set (Street and Grove, 1976,1979): LOW 0-15% of the total altitudinal range of fluctuation, including dry lakes INTERMEDIATE 15-70% of the total range HIGH 70-100% of the total range of fluctuation, including overflowing lakes. For basins where the absolute range of lake levels could not be determined, the relative lake level was coded in the following way: when the lake was at or near its deepest or freshest, it was coded as HIGH and when at or near its lowest or most saline, as LOW. Periods for which there was unambiguous evidence that the lake fell between these states were assigned to the INTERMEDIATE class. For many of the basins in the data bank, a continuous record of water level has been published or made available to us. In such cases, it was possible to determine the trend in water level at 1000-year intervals as RISING, STABLE or FALLING. If no trend information was available for a particular time period, trend was classified as UNCODABLE. 2. Dating Control Dating control is a relative ranking of the quality of the chronology used to select the following time levels: 18 ka BP; 15 ka BP 12 ka BP 9 ka BP 6 ka BP and 3 ka BP. Two different schemes were applied, depending on whether the dates were derived from a continuous sequence such as a core or from discontinuous samples such as shoreline tufas; the dating control was assessed for each time period on a scale of decreasing quality ranging from one to seven. The coding for continuous sequences was based on the following criteria (extended from Webb, 1985): 1. Bracketting dates within 2000 years of the selected date. The top of a continuous core can be assigned a date of 0 ka BP. 2. Bracketting dates, one within 2000 years and the other within 4000 years of the selected date. 3. Bracketting dates within 4000 years of the selected date. 4. Bracketting dates, one within 4000 years and the other within 6000 years of the selected date. 5. Bracketting dates within 6000 years of the selected date. 6. Bracketting dates, one within 6000 years and the other within 8000 years OR one within 4000 years and the other within 10,000 years of the selected date. 7. Undated at selected date: either no dates in the core, no bracketing dates, no top to core and no date within 8000 years of the selected date, or bracketing dates more than 14,000 years apart. 0. Status uncodable for selected date regardless of availability of radiocarbon dates. Additionally, a ranking of 1 was allotted to a continuous sequence if there was a single date within 2o or 250 years of the selected level. The coding for discontinuous sequences was based on the following criteria (extended from Webb, 1985): 1. At least one radiocarbon date within 250 years of the selected level. 2. At least one radiocarbon date within 500 years of the selected level. 3. At least one radiocarbon date within 750 years of the selected level. 4. At least one radiocarbon date within 1000 years of the selected level. 5. At least one radiocarbon date within 1250 years of the selected level. 6. At least one radiocarbon date within 2000 years of the selected level. 7. Radiocarbon date(s) more than 2000 years from the selected level. 0. Status uncodable for selected level regardless of availability of radiocarbon dates. APPENDIX B. DESCRIPTION AND FORMAT OF THE OXFORD LAKE-LEVEL DATA BANK The Oxford Lake-Level Data Bank comprises records of lake status, a measure of relative water depth, for lake basins which have been closed for part, or all, of their Late Quaternary history. The data base is arranged regionally in the following order: Africa; South and Southwest Asia (including Afghanistan and India); China; Soviet Union; North America (U.S.A. and Canada, in that order); Mexico; South and Central America; Australasia (Australia, New Zealand and Papua New Guinea, in that order); Europe and Greenland. Within each regional block the order of the basins is alphabetical. For North America, basins are listed alphabetically by state or province. The full data bank is stored, in slightly different formats, in the files "lakedata.txt" and "lakeres.txt." These files contain the lake status and trend codes, with information about supporting radiocarbon dates for each 1000-year time slice for each basin. Each basin is uniquely identified by a COHMAP Basin number, called the Brown Master Number (BMN) (see Appendix C; lakelevindex.txt). This number permits quick reference to be made between the full data bank and supporting files (Appendices C, D and E; lakelevindex.txt, pubindex.txt, and numrefs.txt). "lakeres.txt" contains headings to help the reader understand the data. However, "lakedata.txt" contains the raw data without descriptive headings. Therefore, its format is described below. Format of the file "lakedata.txt" The first line of the data base provides information about the first lake in the file, Lake Abhe, Ethiopia. The beginning of the information for each basin is signified by a line with its name, location and Brown Master Number. The number of lines required for each basin is variable, depending on the number of time periods classified and the number of radiocarbon dates for each time period. However, the format of lines 1-6 is the same for each basin. The format for the remainder of each basin entry is flexible, depending on the number of time periods and the available dating control. The following information is included for each basin: 1st line - columns 1-35 basin name (state or province) and country columns 37-42 latitude as a decimal (+ve values for Northern Hemisphere and -ve values for Southern Hemisphere) columns 46-52 longitude as a decimal (+ve values for Eastern Hemisphere and -ve values for Western Hemisphere) columns 55-58 Brown Master Number - a sequential code identifying each basin by the order in which it was added to the data base; 2nd-5th lines - a quick guide to source references, including those with radiocarbon dates, along with any important qualifying information; 6th line - columns 1- 2 time period (1 = present day, 2 = 1 ka BP, 3 = 2 ka BP, etc.) column 4 lake status (1 = high, 2 = intermediate, 3 = low, 0 = uncodable) column 6 lake trend (1 = rising, 2 = stable, 3 = falling, 0 = uncodable) columns 10-11 number of radiocarbon dates within the corresponding time period If there are no radiocarbon dates for a time period, the following line provides the same information as line 6 for the preceding time period. If radiocarbon dates are available there follow two additional lines for each date with the following structure: line A columns 8-11 radiocarbon date in years BP columns 16-20 +ve standard error of the radiocarbon date columns 26-30 -ve standard error of the the radiocarbon date line B columns 4-5 number of reference listing radiocarbon date (see lines 2-5 above) columns 6-15 laboratory number of the radiocarbon date columns 16-132 information about the material dated, its location and validity (see below for list of abbreviations used) After the two lines of information for each radiocarbon date for a given time period have been entered, the succeeding line contains either the information for the next time period (in the same format as line 6 above), or, if there is no more information for this basin, the terminator '808080 80' in columns 1-11. The end of the data bank is signified by the terminator '909090 90' in columns 1-11. The format of "lakedata.txt" is illustrated below. FORMAT OF THE FILE "lakedata.txt" 1 1 2 3 4 5 6 7 3 1234567890123456789012345678901234567890123456789012345678901234567890.....56789012 BASIN, STATE OR PROVINCE, COUNTRIES LATITU LONGITU BMN# R#> AUTHORS,DATE AUTHORS,DATE .... .... .... .... .... ..... ....COMMENTS1.... TP S T #C14 ESTAG SE+VE SE-VE R# LABNUM MATERIAL DATED AND COMMENTS . . . TP S T #C14 ESTAG SE+VE SE-VE R# LABNUM MATERIAL DATED AND COMMENTS . . . . . . 808080 80 BASIN, STATE OR PROVINCE, COUNTRIES LATITU LONGITU BMN# . . . 808080 80 . . . 909090 90 where 1234... = columns LATITU = basin latitude in decimal form; positive values for Northern Hemisphere, negative values for Southern Hemisphere; columns 37-42. LONGITU = basin longitude in decimal form; positive values for Eastern Hemisphere, negative values for Western Hemisphere; columns 46-52. BMN# = Brown University Master Number; columns 55-58 R# = reference number - used to identify sources of radiocarbon dates .... = continuation of information in same format COMMENTS1 = comments relating specifically to the references; not present for all basins; follows immediately after last reference or at beginning of next line TP = Time Period; 1000 year periods centered on the millenia; columns 1-2 e.g., TP 1 = 0 yr BP (covers period 0 - 499 yr BP), TP 2 = 1000 yr BP (covers period 500 - 1499 yr BP) . . TP 31 = 30000 yr BP (covers period 29500-30499 yr BP) S = lake level status; column 4 3 = LOW; 2 = INTERMEDIATE; 1 = HIGH; 0 = UNCODABLE T = lake level trend; column 6 3 = FALLING; 2 = STABLE; 1 = RISING; 0 = UNCODABLE #C14 = number of radiocarbon dates falling within the time period under consideration, columns 8-11 ESTAG = radiocarbon age of the sample analyzed; columns 6-10 SE+VE = positive standard error of the radiocarbon age; columns 16-20 SE-VE = negative standard error of the radiocarbon age; columns 26-30 LABNUM = Laboratory analyzing the sample and the assigned sample number; columns 6-15 C0MMENTS2 = comments relating specifically to the sample, e.g., clarifying its location or elevation, stating any problems with the date; see 'ABBREVIATIONS USED IN THE DATA BASE' for further clarification; along with MATERIAL DATED found in columns 16-132 808080 80 = terminator the information for this basin; columns 1-11 909090 90 = terminates the data base (also the end of information for the last basin in the listing); columns 1-11. Abbreviations used in the Data Bank No Data 0 Numeric columns N.A. Not available PCNA Permanent lab. number unavailable; temporary number given in source reference used Lake Level (Used if individual dates disagree with classification of time period or for clarification) S1 High (= status 1) S2 Intermediate S3 Low Sediment (Describes sediment type) SEDS. Sediments (e.g., CORE SEDS.) L Lacustrine or lake LK Lacustrine or lake NL Nonlacustrine (e.g., for charcoal in soils) FL Fluviolacustrine M Marsh deposits LSST Lake-side archaeological site, indicates lake nearby ARCH SITE Stratigraphically-related archaeological site, but not lake-side LST Limestone / Overlying (e.g., where dated deposit overlies beach material) Materials (Describes materials dated} MATL. UNCERT. Material unknown or reference ambiguous PROB. - Reference ambiguous but implies - QUERY MATL. Used where reference unclear or description doubtful PLANT MACRO Plant macrofossils DIAT. MARL Diatomaceous marl DIAT. Diatomite CALCAR. CRUST Calcareous crust (may be pedogenic) STROMAT. Stromatolite or stromatolitic (e.g., STROMAT. LST.) LST. Limestone SHELLS Shells (taxon given if known e.g., MELANOIDES SHELLS, otherwise type given e.g., NL SHELLS) PROB. SHELL Probably a date on shell (see note above) REWORKED or Where reworking of dated material known to RWKD have occurred PROB. RWKD Where reworking of dated material suspected WXED Dated material shows signs of weathering, and may be RWKD CONCN. Concentration INN. Inner fraction (e.g., of shells, carbonate nodules) dated OUT. Outer fraction (e.g., of shells, carbonate nodules) dated CARB. Dated on carbonate fraction (CaC03). This often follows MARL, ALGAL LST or TUFA, to clarify fraction dated. ARAG. Aragonite AUTH. Authigenic W/ With BONE Bone. Fraction dated (e.g., APATITE or COLLAGEN) usually given if known. Identification (e.g., GIRAFFE BONE) usually given if known. ORG.FR. Organic fraction dated (e.g., of CORE MATL.) HUM. Humic MATRIX Matrix of CORE MATL. Core material DISS. Disseminated (usually applies to ORG. FR. or CHARCOAL) EVAPTS. Evaporites Validity (Assessment of validity of a radiocarbon date) QUERY DATE Suspected typographical or other error in date QUERY S.D. Suspected typographical or other error in standard error VD Validity doubtful, based on source reference CS Contamination suspected, based on source reference ATY Age too young, based on source reference ATO Age too old, based on source reference ATO, REJECT Date definitely invalid and therefore not used in assessment POSS. ATY Assessment based on reinterpretation of source reference or on new data POSS. ATO Assessment based on reinterpretation of source reference or on new data STRATIG. INCONSIST. Date stratigraphically inconsistent QUERY DIAGENESIS Diagenesis suspected, and may be cause of invalid date STRATIG. ERR. Stratigraphic error TH- Corresponding uranium-series date AV( ) Date cited is an average of ( ) number of determinations Relation to other dates DUPL. Duplicate; lab number of other date usually cited for reference Other (Information relating to interpretation of data) MIN. AGE FOR Dated material gives minimum age for (e.g., MIN. AGE FOR BEACH indicates that date derived from an overlying unit or material which must post-date lake, such as packrat midden material from a lake-shore cave) ALMOST CERTAINLY INFINITE Date probably beyond the range of radiocarbon dating, usually associated with VD,CS SIGNIF. UNCERT. Significance of a date in relation to lake- level history uncertain. May be applied to dates that are difficult to interpret or archaeological dates where exact relation to shoreline position is unclear. Specific comments on individual basins COCHISE, ARIZONA WWM Willcox White Marl LGC Lower Green Clay IG Intermediate Gravel UGC Upper Green Clay SEARLES, CALIFORNIA BM Bottom Mud LS Lower Salt PM Parting Mud US Upper Salt OM Overburden Mud ( ) Indicates inferred correlation (/used here for or) Core numbers are listed e.g., L-U-1 BONNEVILLE, UTAH AF Alpine Formation WM White Marl, Bonneville Formation UM Upper Member, Bonneville Formation DF Draper Formation TULARE, CALIFORNIA BVL Buena Vista Lake