noaa-lake-17349 Lake Bosumtwi, Ghana 2700 Year Spatial Geochemical and Isotope Data Shanahan, T.M.; McKay, N.P.; Overpeck, J.T.; Peck, J.A.; Scholz, C.A.; Heil, C.W.; King, J.C. Lake Bosumtwi, Ghana 2700 Year Spatial Geochemical and Isotope Data 2014-10-19 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/17349 Investigator Shanahan, T.M. Investigator N.P. McKay Investigator J.T. Overpeck Investigator J.A. Peck Investigator C.A. Scholz Investigator C.W. Heil Investigator J.C. King earth science paleoclimate paleolimnology carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,null,elemental analysis,N,bulk organic carbon/bulk organic nitrogen earth science paleoclimate paleolimnology aluminum,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology notes,null,null,meter,null,paleolimnology,null,null,N,distance from shoreline earth science paleoclimate paleolimnology sample identification,null,null,null,null,paleolimnology,null,null,C,null earth science paleoclimate paleolimnology nitrogen,sediment,null,percent,null,paleolimnology,null,elemental analysis,N,organic nitrogen earth science paleoclimate paleolimnology grain size mean,sediment,null,micrometer,null,paleolimnology,null,laser particle size analysis,N,null earth science paleoclimate paleolimnology longitude,null,null,degree east,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology organic carbon,sediment,null,percent,null,paleolimnology,null,elemental analysis,N,bulk analysis (soil / veg / sed) earth science paleoclimate paleolimnology delta 13C,organic matter,null,per mil,null,paleolimnology,null,isotope ratio mass spectrometry,N,null earth science paleoclimate paleolimnology titanium,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology iron,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology silicon,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology calcium,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology grain size standard deviation,sediment,null,micrometer,null,paleolimnology,null,laser particle size analysis,N,degree of sorting earth science paleoclimate paleolimnology delta 15N,organic matter,null,per mil,null,paleolimnology,null,isotope ratio mass spectrometry,N,null earth science paleoclimate paleolimnology manganese,sediment,null,count per second,null,paleolimnology,null,energy-dispersive x-ray fluorescence spectroscopy,N,null earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology latitude,null,null,degree north,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology collection water depth,null,null,meter,null,paleolimnology,null,null,N,water depth of lake earth science paleoclimate paleolimnology organic carbon,sediment,null,percent,null,paleolimnology,null,elemental analysis,N,null earth science paleoclimate paleolimnology geochemistry geoscientificInformation 2668 cal yr BP -53 cal yr BP Complete 6.5 6.5 -1.4167 -1.4167 99 99 Continent Africa Western Africa Ghana Lake Bosumtwi>LATITUDE 6.5>LONGITUDE -1.4167 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Timothy M. Shanahan, Nicholas McKay, Jonathan T. Overpeck, John A. Peck, Christopher Scholz, Clifford W. Heil Jr., John King 2013 Palaeogeography, Palaeoclimatology, Palaeoecology 374 96-109 10.1016/j.palaeo.2013.01.008 http://www.sciencedirect.com/science/article/pii/S0031018213000126

The physical, inorganic and organic geochemical and stable isotopic characteristics of lacustrine sediments can provide valuable insights into past environmental changes, provided that the environmental controls on these characteristics are well understood. In the present study, a set of 155 modern vegetation, catchment soil, river sediments and lake surface sediment samples are used to characterize the spatial patterns of TOC, TN, C/N ratios, stable isotope, major element, and particle size distributions within Lake Bosumtwi, a meromictic crater lake in West Africa. Spatial variations in sediment characteristics are strongly correlated with depth and distance from shore, reflecting the dominant influence of lake level on the relative proportions of littoral and pelagic depositional systems and their impact on the physical and geochemical properties of lacustrine sediments. This is supported by a principal component analysis, which indicates that 65% of the variance in the dataset is explained by depth-related variability in the sedimentary components. Variations in sedimentary organic matter reflect the combined influences of productivity, preservation and the relative proportions of aquatic and terrestrial organic matter sources. Grain size and Si content are dominantly influenced by the delivery of clastic materials from the watershed to the lake, whereas Fe and Ca appear to be most strongly influenced by the delivery of reduced metals and nutrients from the anoxic hypolimnion to the surface. With the exception of grain size, all of the sediment parameters record synchronous century-scale variability over the past ~2.5 ka, consistent with independent evidence for changes in lake level. However, the magnitude of changes in sediment characteristics differs, reflecting different sensitivities to water depth, particularly in the deepest part of the lake basin where the sediment cores were collected. However, even the parameters with the most linear and strongly significant relationships with depth (e.g., TOC, TN) significantly overestimate the magnitude of lake level changes, suggesting that these parameters may be best suited to qualitative paleolake level reconstructions. Over the last 2 centuries, changes in C/N and d13C became decoupled from the other geochemical proxies and the inferred rise in lake level. We hypothesize that this reflects the influence of anthropogenic land use change on the composition of terrestrial organic matter sources contributing to the lake. This result highlights the potential difficulties in reconstructing past environmental changes from indirect proxy measurements when those proxies may be subject to multiple varying controls. STUDY NOTES: Surface and downcore geochemical and isotope data from Lake Bosumtwi, Ghana for the past 2700 years.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2013spatial-surface.txt Data File; Surface sediment physical and geochemical data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2013spatial-chem-iso.txt Data File; Bulk Organic geochemistry and stable isotopes GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2013spatial-gs.txt Data File; Grain size analysis GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2013spatial-xrf.txt Data File; Downcore XRF elemental data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11