Bear Lake, Utah-Idaho Geochemical and Mineralogical Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Bear Lake, Utah-Idaho Geochemical and Mineralogical Data LAST UPDATE: 3/2009 (Original receipt by WDC Paleo) CONTRIBUTOR: Walter E. Dean, U. S. Geological Survey, Denver, Colorado IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2009-028 WDC PALEO CONTRIBUTION SERIES CITATION: Dean, W.E. 2009. Bear Lake, Utah-Idaho Geochemical and Mineralogical Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2009-028. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCES: Dean, W.E., R. Forester, S. Colman, A. Liu, G. Skipp, K. Simmons, P. Swarzenski, and R. Anderson. 2005. Modern and Glacial-Holocene Carbonate Sedimentation in Bear Lake, Utah-Idaho. U.S. Geological Survey Open-File Report 2005-1124. (http://pubs.usgs.gov/of/2005/1124) Dean, W.E., R.M. Forester, J. Bright, and R.Y. Anderson. 2007. Influence of the diversion of Bear River into Bear Lake (Utah and Idaho) on the environment of deposition of carbonate minerals: Evidence from water and sediments. Limnology and Oceanography, v. 52, p. 1094-1111. Dean, W.E. 2009. Endogenic carbonate sedimentation in Bear Lake, Utah and Idaho over the last two glacial-interglacial cycles, in Rosenbaum, J.G., and Kaufman, D.S., eds., Paleoenvironments of Bear Lake, Utah and Idaho, and Its Catchment. Geological Society of America, Special Paper 450, ISBN: 9780813724508 GEOGRAPHIC REGION: Western North America PERIOD OF RECORD: 25 KYrBP - present FUNDING SOURCES: U.S. Geological Survey DESCRIPTION: Piston cores were collected in 1996 from three localities in Bear Lake using the University of Minnesota, Limnological Research Center's (UMN-LRC) Kullenberg coring system (Dean et al., 2006). Core BL96-1 is 5 m long from a water depth of 50 m. Core BL96-2 is 4 m long from a water depth of 40 m. Core BL96-3 is 4 m long from a water depth of 30 m. Overlapping cores provide a 25,000-year record. Unknown amounts of sediments were missing from the tops of the piston cores, so surface sediments (up to 50 cm) were collected with a gravity corer in 1998 (Dean et al., 2007). Core BL98-4 is 17 cm m long from a water depth of 30 m. Core BL98-6 is 20 cm long from a water depth of 30 m. Core BL98-9 is 30 cm long from a water depth of 40 m. Core BL98-10 is 36 cm long from a water depth of 40 m. Core BL98-12 is 38 cm long from a water depth of 30 m. Core BL98-13 is 36 cm long from a water depth of 30 m. Piston cores and gravity cores were collected at five localities at the northern end of the lake in 2002. Geochemical and mineralogical data were collected on two of the piston cores and gravity cores from the same localities. Core BL02-3PC is 475 cm long and BL02-3GC is 15 cm long, both from a water depth of 40 m. Core BL02-4PC is 380 cm long and BL02-4GC is 40 cm long, both from a water depth of 30 m. The data set includes files of carbon data, X-ray diffraction (XRD) mineralogy, carbon- and oxygen-isotope data on bulk carbonate, Sr isotope data on bulk carbonate, and HCl-leach chemistry. Not all data were collected on sediments from all cores. Bear Lake: 42°0'N, 111°20'W, 1805m elev. BEAR LAKE METHODS: Carbon Analyses Concentrations of total carbon and inorganic (total carbonate) carbon were determined by coulometry (Engleman and, others, 1985) in USGS laboratories in Denver, CO. Inorganic carbon (IC) in the untreated sample is reacted with perchloric acid to liberate CO2, which is then titrated in a coulometer cell to measure carbonate carbon. Total carbon (TC) is measured by liberating CO2 by combustion of an untreated sample and titrating the CO2. Values of organic carbon (OC) were determined by difference between TC and IC. Replicate analyses demonstrate the coulometer technique has a precision of better than ±1% for both carbonate and total carbon. Percent CaCO3 was calculated by dividing percent carbonate carbon by 0.12, the fraction of carbon in CaCO3. Reference: Engleman, E. E., Jackson, L. L., Norton, D. R., and Fischer, A. G., 1985, Determination of carbonate carbon in geological materials by coulometric titration. Chemical Geology, v. 53, p. 125-128. Isotope Analyses Measurements of ratios of stable isotopes of carbon and oxygen were made on aliquots of the carbon samples (see Dean et al., 2006, 2007 for methods). Isotope measurements on samples from the 1996 cores, 1998 cores, and sediment traps were made in the stable isotope laboratory at the University of Minnesota. Isotope measurements on samples from the 2002 cores were made in the stable isotope laboratory at the University of Arizona. Results of analyses are reported in the usual per mil (‰) d-notation relative to the Vienna Pee Dee Belemnite (VPDB) marine-carbonate standard for carbon and oxygen: d‰=[(Rsample/RVPDB)-1]x103 where R is the ratio (13C:12C) or (18O:16O). Measurements of Sr isotope ratios (86Sr/87Sr) were made on samples from six cores, in Samples were leached in 5M acetic acid, and the leachate was centrifuged and purified with conventional ion-exchange methods. Samples were loaded on a single tantalum filament with phosphoric acid. Isotope ratios were measured with an automated VG54 sector multi-collector, thermal ionization mass spectrometer in dynamic mode. Mass dependent fractionation was corrected assuming a 86Sr/87Sr ratio of 0.1194. Strontium isotope ratios are reported relative to SRM-987 standard value of 0.71025. X-ray Diffraction Analyses Semi-quantitative estimates of mineral contents in splits of the carbon samples were determined by standard X-ray diffraction (XRD) techniques (e.g., Moore and Reynolds, 1989) in USGS laboratories in Denver, CO. Each sample was packed into an aluminum holder and scanned from 15° to 50° 2Q at 2° 2Q/min using Ni-filtered, Cu-Ka radiation at 45 kv, 30 ma, and peak intensities recorded as counts per second (cps). Results are reported as the peak intensity of the main XRD peak for each mineral. Reference: Moore, D.M., and Reynolds, R.C., Jr., 1989. X-ray diffraction and identification and analysis of clay minerals. Oxford University Press, 332 pp. Inorganic Geochemical Analyses Samples for inorganic geochemical analyses were leached in 3N HCl overnight, and the supernatant was analyzed by inductively coupled, argon-plasma, atomic-emission spectrometry (ICP-AES) for major components (percent) Ca, Fe, and Mg, and minor components (parts per million, ppm) Na, Mn, Ba, Sr and Li (Bischoff et al., 2005). Reference: Bischoff, J.L., Simmons, K., and Shamp, D.D., 2005. Geochemistry of sediments in Bear Lake cores and sediment traps. U.S. Geol. Survey, Open-File Report 2005-1215. http://pubs.usgs.gov/of/2005/1215. Abbreviations: cmblf, centimeters below lake floor; VPDB, Vienna Pee Dee Belemnite marine-carbonate standard for carbon and oxygen isotopes DATA: 1. BL98-4 carbon Depth depth in core in cm below lake floor % TC percent total carbon by coulometry % IC percent inorganic carbon by coulometry % OC percent organic carbon by difference between TC and IC % CaCO3 percent calcium carbonate = % IC/0.12 Depth %TC %IC %OC %CaCO3 1 8.28 6.93 1.35 57.75 2 8.37 7.03 1.34 58.58 3 8.54 7.17 1.37 59.75 4 8.44 7.09 1.35 59.08 5 8.04 7.23 0.81 60.25 6 8.95 7.24 1.71 60.33 8 8.89 7.33 1.56 61.08 10 9.08 7.9 1.18 65.83 12 8.91 7.65 1.26 63.75 14 8.6 7.32 1.28 61 16 9.01 8.12 0.89 67.67 2. BL98-4 stable isotopes Depth depth in core in cm below lake floor 13C (VPDB) delta 13C relative to standard VPDB 18O (VPDB) delta 18O relative to standard VPDB Depth 13C 18O 1 0.63 -7.27 2 0.8 -7.22 3 0.86 -7.2 4 0.76 -7.07 5 0.82 -7.14 6 1.01 -6.89 8 2.02 -5.81 10 2.71 -3.95 12 2.59 -4.29 14 2.56 -4 16 2.25 -4.37