The chronostratigraphy of Holocene sediments from four Lake Superior sub-basins1Laboratory for Stable Isotope Science (LSIS) Contribution 264.

2011 ◽  
Vol 48 (12) ◽  
pp. 1581-1599 ◽  
Author(s):  
Ayumi Hyodo ◽  
Fred J. Longstaffe
Keyword(s):  
Lake Superior ◽  
Sediment Cores ◽  
Carbonate Content ◽  
Radiocarbon Dates ◽  
Glacial Sediments ◽  
Fine Grained ◽  
Isotopic Compositions ◽  
Stable Isotopic ◽  
Oxygen Isotopic ◽  
Glacial Clays

Radiocarbon dates, rhythmite occurrences, mineralogy, grain size, and stable isotopic compositions of detrital calcite obtained for four sediment cores from Lake Superior have been used to produce a chronology for these fine-grained deposits over the last ∼10 500 cal BP (calibrated years before A.D. 1950). Most of the rhythmites have been interpreted as annual laminations (varves) based on systematic variations in the carbonate content of rhythmite couplets and correlation of the rhythmite packages with varve sequences reported previously for Lake Superior sediments. Glacial sediments in these cores, which consist of red and grey clay, range in age from ∼10 500 to 8800–8700 cal BP. Distinctive carbon and oxygen isotopic compositions of allochthonous calcite in the red versus grey glacial clays point to different sources for this detritus. Final termination of glacial meltwater input into the Lake Superior Basin occurred between 9000 and 8700 cal BP. The significant decrease in sediment carbonate content over this time is a convenient marker for the start of postglacial sedimentation across the Lake Superior Basin.

Fine-grained, spinel-rich inclusions from the reduced CV chondrite Efremovka: II. Oxygen isotopic compositions

2005 ◽  
Vol 40 (7) ◽  
pp. 1043-1058 ◽  
Author(s):  
Jérôme ALÉON ◽  
Alexander N. KROT ◽  
Kevin D. MCKEEGAN ◽  
Glenn J. MACPHERSON ◽  
Alexander A. ULYANOV
Keyword(s):  
Fine Grained ◽  
Isotopic Compositions ◽  
Oxygen Isotopic

Quantitative Estimates of Temperature Changes Over the Last 2700 Years in Michigan Based on Pollen Data

1981 ◽  
Vol 15 (2) ◽  
pp. 143-159 ◽  
Author(s):  
J. Christopher Bernabo
Keyword(s):  
Sediment Cores ◽  
The Other ◽  
Stratigraphic Correlation ◽  
Calibration Function ◽  
Climate Data ◽  
Pollen Data ◽  
Radiocarbon Dates ◽  
Temperature Changes ◽  
Fine Grained ◽  
Modern Pollen

AbstractTemperatures for the past 2700 yr are estimated using well-dated pollen data from northwestern lower Michigan. The pollen data were sampled from sediment cores of four lakes along a 75-km transect, with fine-grained morainic soils around the two western lakes and sandy outwash soils around the lakes to the east. Climatic reconstructions based on the pollen data from the sandy sites show less temperature change than the reconstructions from the other sites, because variations in the composition of the vegetation at the sandy sites are edaphically restricted. One of the cores studied was dated by counting visible annual laminations (varves). The cores from the other lakes were dated based on three radiocarbon dates per core as well as the historically determined age of the settlement horizons. All the time scales were cross-checked using pollen-stratigraphic correlation between the four sites. A calibration function was developed using a network of modern pollen and climate data covering all of lower Michigan. Based on this calibration function, the 2700-yr reconstruction for Marion Lake indicates an estimated growing-season temperature range of 1.3°C between extreme 30-yr means. Mild conditions persisted prior to ca. A.D. 400, but a cold interval occurred between ca. A.D. 500 and 800. The well-marked warm period evident from ca. A.D. 1000 to 1200 was the last time when temperatures were about equal to the 1931–1960 mean. A prolonged longed cooling occurred after A.D. 1200 and reached 1°C below the 1931–1960 mean by the 1700s. A warming of 0.5°C is indicated from ca. A.D. 1750 to 1850. The estimated temperatures for the 1830s at Marion Lake agree with the instrumental data for that period and this provides some validation of the calibration-function results.

ON THE TIMING OF THE OLD COPPER COMPLEX IN NORTH AMERICA: A COMPARISON OF RADIOCARBON DATES FROM DIFFERENT ARCHAEOLOGICAL CONTEXTS

Radiocarbon ◽  
2021 ◽  
pp. 1-19
Author(s):  
David P Pompeani ◽  
Byron A Steinman ◽  
Mark B Abbott ◽  
Katherine M Pompeani ◽  
William Reardon ◽  
...  
Keyword(s):  
Native American ◽  
Lake Sediment ◽  
Copper Complex ◽  
Lake Superior ◽  
Copper Mining ◽  
Radiocarbon Dates ◽  
Copper Mines ◽  
Tool Technology ◽  
High Lead ◽  
Old Copper Complex

ABSTRACT The Old Copper Complex (OCC) refers to the production of heavy copper-tool technology by Archaic Native American societies in the Lake Superior region. To better define the timing of the OCC, we evaluated 53 (eight new and 45 published) radiocarbon (14C) dates associated with copper artifacts and mines. We compared these dates to six lake sediment-based chronologies of copper mining and annealing in the Michigan Copper District. 14C dates grouped by archaeological context show that cremation remains, and wood and cordage embedded in copper artifacts have ages that overlap with the timing of high lead (Pb) concentrations in lake sediment. In contrast, dates in stratigraphic association and from mines are younger than those from embedded and cremation materials, suggesting that the former groups reflect the timing of processes that occurred post-abandonment. The comparatively young dates obtained from copper mines therefore likely reflect abandonment and infill of the mines rather than active use. Excluding three anomalously young samples, the ages of embedded organic material associated with 15 OCC copper artifacts range from 8500 to 3580 cal BP, confirming that the OCC is among the oldest known metalworking societies in the world.

Reconstructing Terrestrial Environments Using Stable Isotopes in Fossil Teeth and Paleosol Carbonates

2012 ◽  
Vol 18 ◽  
pp. 167-194 ◽  
Author(s):  
Benjamin H. Passey
Keyword(s):  
Isotopic Composition ◽  
Soil Temperature ◽  
Carbon Isotopes ◽  
Oxygen Isotopes ◽  
Precipitation Amount ◽  
Radiative Heating ◽  
Mammal Species ◽  
Isotopic Compositions ◽  
Heat Effects ◽  
Oxygen Isotopic

Carbon isotopes in Neogene-age fossil teeth and paleosol carbonates are commonly interpreted in the context of past distributions of C3 and C4 vegetation. These two plant types have very different distributions in relation to climate and ecology, and provide a robust basis for reconstructing terrestrial paleoclimates and paleoenvironments during the Neogene. Carbon isotopes in pre-Neogene fossil teeth are usually interpreted in the context of changes in the δ13C value of atmospheric CO2, and variable climate-dependent carbon-isotope discrimination in C3 plants. Carbon isotopes in pre-Neogene soil carbonates can be used to estimate past levels of atmospheric CO2. Oxygen isotopes in fossil teeth and paleosol carbonates primarily are influenced by the oxygen isotopic compositions of ancient rainfall and surface waters. The oxygen isotopic composition of rainfall is has a complex, but tractable, relationship with climate, and variably relates to temperature, elevation, precipitation amount, and other factors. Mammal species that rely on moisture in dietary plant tissues to satisfy their water requirements (rather than surface drinking water) may have oxygen isotopic compositions that track aridity. Thus, oxygen isotopes of fossil mammals can place broad constraints on paleoaridity. Carbonate clumped isotope thermometry allows for reconstruction of soil temperatures at the time of pedogenic carbonate mineralization. The method is unique because it is the only thermodynamically based isotopic paleothermometer that does not require assumptions about the isotopic composition of the fluid in which the archive mineral formed. Soil temperature reflects a complex interplay of air temperature, solar radiative heating, latent heat effects, soil thermal diffusivity, and seasonal variations of these parameters. Because plants and most animals live in and/or near the soil, soil temperature is an important aspect of terrestrial (paleo)climate.

The Hayes Tephra Deposits, and Upper Holocene Marker Horizon in South-Central Alaska

1990 ◽  
Vol 33 (3) ◽  
pp. 276-290 ◽  
Author(s):  
James R. Riehle ◽  
Peter M. Bowers ◽  
Thomas A. Ager
Keyword(s):  
Cook Inlet ◽  
Radiocarbon Dates ◽  
Fine Grained ◽  
South Central ◽  
Inlet Region ◽  
Tephra Deposits ◽  
Phenocryst Content

AbstractThe most widespread of all Holocene tephra deposits in the Cook Inlet region of south-central Alaska is a set of deposits from Hayes volcano. Because of their unique phenocryst content—biotite in rare amounts and a high proportion of amphibole to pyroxene—the deposits are readily identifiable at all but the most distant sites where they are very fine grained. Eighteen radiocarbon dates from eight upland sites limit the age of the tephra set to between about 3500 and 3800 yr. The set originated at Hayes volcano in the Tordrillo Mountains 150 km northwest of Anchorage; seven or possibly eight closely succeeding deposits, low-silica dacite in composition, compose two main lobes that extend northeast for 400 km and south for at least 250 km from the vent. We estimate the total tephra volume to be 10 km3; multiple layers imply four to six larger and two or three smaller eruptions. The deposits are a nearly isochronous marker horizon that should be useful in future archeologic, geologic, and palynologic studies in the region.

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