S W Leavitt
Biographic Data
| ID | 5597525 |
|---|---|
| NAME | S W Leavitt |
| GIVEN NAMES | S W |
| FAMILY NAME | Leavitt |
| SIGNATURE | LEAVITT S W |
| VERIFIED | No |
| TOTAL WORKS | 7 |
| TOTAL CITATIONS | 13 |
| WORKS AS AUTHOR | 7 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1982 |
| LATEST PUBLICATION YEAR | 1996 |
| H-INDEX | 2 |
Estimation of Slow- and Fast-Cycling Soil Organic Carbon Pools from 6N HCl Hydrolysis
Acid hydrolysis is used to fractionate the soil organic carbon pool into relatively slow- and fast-cycling compartments on soils from Arizona, the Great Plains states and Michigan collected for carbon isotope tracer studies related to soil carbon sequestration, for studies of shifts in C 3 /C 4 vegetation, and for “pre-bomb” soil-carbon inventories. Prior to hydrolysis, soil samples are first treated with cold 0.5–1N HCl to remove soil carbonates…
Δ 13 C Variations in C 3 Plants Over the Past 50,000 Years
We examined three sets of data to determine if there are consistent changes in δ 13 C of C 3 plants through time, under the hypothesis that environmental changes from glacial to postglacial may have caused such isotopic changes over the last 50 ka. The records of δ 13 C change in all types of plant data from Radiocarbon and from the University of Arizona Radiocarbon Laboratory archives both reveal significant decline of 0.8–1.0‰ in δ 13 C from pr…
The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States
We have developed a master δ 13 C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt…
Accelerator-Measured 14C Activity in Tree Rings From the Vicinity of the First Atomic Bomb Test
Detonation of the first fission bomb at White Sands, New Mexico, on July 16, 1945, produced a tremendous neutron flux capable of creating tritium and radiocarbon byproducts. We sampled a 115-year-old pinyon (Pinus edulis) 10km east of the Trinity test site to determine 14 C evidence of this event. The most likely mechanism for this enrichment in the 1945 tree ring would be fixation of 14 CO 2 produced at the blast site and carried with the fallou…
Variation of Concentration, 14C Activity and 13C/12C Ratios of CO2 in Air Samples from Kitt Peak, Arizona
Air was sampled with 5L flasks at Kitt Peak (2100m elev) from 1983 through 1984 at approximately monthly intervals, occasionally supplemented with air samples from urban Tucson ca 75km away (760m elev). The Kitt Peak CO 2 concentrations, represented by a yield measurement, fluctuated ca 25% over the monitoring period. The δ 13 C values (uncorrected for N 2 O) varied from ca −7.6 to −9.0, with high values (and low CO 2 yields) in the late summer c…
Trends of 13 C/ 12 C Ratios in Pinyon Tree Rings of the American Southwest and the Global Carbon Cycle
An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon ( Pinus edulis ) trees, where cores of 4 trees from each site have been pooled into a composite sample. I…
Charcoal production from wood and cellulose
Radiocarbon dating with accelerators requires the manufacture of suitable carbon targets. Carbon yield and 13 C fractionation were investigated for the simple and direct pyrolysis of wood and cellulose to charcoal. Under continuous vacuum removal of evolved volatiles, carbon yields of 35 to 40% and δ 13 C fractionation of −2.5‰ were observed in the pyrolysis of wood to charcoal, whereas yields of 30% and fractionation of −0.8‰ were obtained in th…
Estimation of Slow- and Fast-Cycling Soil Organic Carbon Pools from 6N HCl Hydrolysis
Acid hydrolysis is used to fractionate the soil organic carbon pool into relatively slow- and fast-cycling compartments on soils from Arizona, the Great Plains states and Michigan collected for carbon isotope tracer studies related to soil carbon sequestration, for studies of shifts in C 3 /C 4 vegetation, and for “pre-bomb” soil-carbon inventories. Prior to hydrolysis, soil samples are first treated with cold 0.5–1N HCl to remove soil carbonates…
The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States
We have developed a master δ 13 C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt…
Δ 13 C Variations in C 3 Plants Over the Past 50,000 Years
We examined three sets of data to determine if there are consistent changes in δ 13 C of C 3 plants through time, under the hypothesis that environmental changes from glacial to postglacial may have caused such isotopic changes over the last 50 ka. The records of δ 13 C change in all types of plant data from Radiocarbon and from the University of Arizona Radiocarbon Laboratory archives both reveal significant decline of 0.8–1.0‰ in δ 13 C from pr…
Trends of 13 C/ 12 C Ratios in Pinyon Tree Rings of the American Southwest and the Global Carbon Cycle
An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon ( Pinus edulis ) trees, where cores of 4 trees from each site have been pooled into a composite sample. I…
Charcoal production from wood and cellulose
Radiocarbon dating with accelerators requires the manufacture of suitable carbon targets. Carbon yield and 13 C fractionation were investigated for the simple and direct pyrolysis of wood and cellulose to charcoal. Under continuous vacuum removal of evolved volatiles, carbon yields of 35 to 40% and δ 13 C fractionation of −2.5‰ were observed in the pyrolysis of wood to charcoal, whereas yields of 30% and fractionation of −0.8‰ were obtained in th…
Variation of Concentration, 14C Activity and 13C/12C Ratios of CO2 in Air Samples from Kitt Peak, Arizona
Air was sampled with 5L flasks at Kitt Peak (2100m elev) from 1983 through 1984 at approximately monthly intervals, occasionally supplemented with air samples from urban Tucson ca 75km away (760m elev). The Kitt Peak CO 2 concentrations, represented by a yield measurement, fluctuated ca 25% over the monitoring period. The δ 13 C values (uncorrected for N 2 O) varied from ca −7.6 to −9.0, with high values (and low CO 2 yields) in the late summer c…
Charcoal production from wood and cellulose
Radiocarbon dating with accelerators requires the manufacture of suitable carbon targets. Carbon yield and 13 C fractionation were investigated for the simple and direct pyrolysis of wood and cellulose to charcoal. Under continuous vacuum removal of evolved volatiles, carbon yields of 35 to 40% and δ 13 C fractionation of −2.5‰ were observed in the pyrolysis of wood to charcoal, whereas yields of 30% and fractionation of −0.8‰ were obtained in th…
Trends of 13 C/ 12 C Ratios in Pinyon Tree Rings of the American Southwest and the Global Carbon Cycle
An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon ( Pinus edulis ) trees, where cores of 4 trees from each site have been pooled into a composite sample. I…
The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States
We have developed a master δ 13 C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt…
Accelerator-Measured 14C Activity in Tree Rings From the Vicinity of the First Atomic Bomb Test
Detonation of the first fission bomb at White Sands, New Mexico, on July 16, 1945, produced a tremendous neutron flux capable of creating tritium and radiocarbon byproducts. We sampled a 115-year-old pinyon (Pinus edulis) 10km east of the Trinity test site to determine 14 C evidence of this event. The most likely mechanism for this enrichment in the 1945 tree ring would be fixation of 14 CO 2 produced at the blast site and carried with the fallou…
Variation of Concentration, 14C Activity and 13C/12C Ratios of CO2 in Air Samples from Kitt Peak, Arizona
Air was sampled with 5L flasks at Kitt Peak (2100m elev) from 1983 through 1984 at approximately monthly intervals, occasionally supplemented with air samples from urban Tucson ca 75km away (760m elev). The Kitt Peak CO 2 concentrations, represented by a yield measurement, fluctuated ca 25% over the monitoring period. The δ 13 C values (uncorrected for N 2 O) varied from ca −7.6 to −9.0, with high values (and low CO 2 yields) in the late summer c…
Δ 13 C Variations in C 3 Plants Over the Past 50,000 Years
We examined three sets of data to determine if there are consistent changes in δ 13 C of C 3 plants through time, under the hypothesis that environmental changes from glacial to postglacial may have caused such isotopic changes over the last 50 ka. The records of δ 13 C change in all types of plant data from Radiocarbon and from the University of Arizona Radiocarbon Laboratory archives both reveal significant decline of 0.8–1.0‰ in δ 13 C from pr…
Estimation of Slow- and Fast-Cycling Soil Organic Carbon Pools from 6N HCl Hydrolysis
Acid hydrolysis is used to fractionate the soil organic carbon pool into relatively slow- and fast-cycling compartments on soils from Arizona, the Great Plains states and Michigan collected for carbon isotope tracer studies related to soil carbon sequestration, for studies of shifts in C 3 /C 4 vegetation, and for “pre-bomb” soil-carbon inventories. Prior to hydrolysis, soil samples are first treated with cold 0.5–1N HCl to remove soil carbonates…
Chemistry (6 works) · Geology (5 works) · Paleontology (5 works) · Radiocarbon dating (5 works) · Environmental Chemistry (4 works) · Environmental Science (4 works) · Physics (4 works) · Stable isotope ratio (4 works) · Tree-ring climate responses (4 works) · δ13C (4 works)