Precise Timing of the Last Interglacial Period from Mass Spectrometric Determination of Thorium-230 in Corals

Edwards, R. Lawrence; Chen, J. H.; Ku, Teh‐Lung; Wasserburg, G. J.

doi:10.1126/science.236.4808.1547

Cited by 344 publications

(157 citation statements)

References 26 publications

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“…U/Th methods in young corals clearly have the potential to meet these demands [Edwards' et al ,1987]; our results represent the first attempt to apply the method to sclerosponges.…”

Section: Chronology and Resolutionmentioning

confidence: 99%

“…However, these methods do not deliver the level of temporal precision that' is necessary for higher-resolution (decadal-scale) paleoceanographic reconstructions. In this study, we use the more precise method of 230Th/234U dating, measured by thermal ionization mass spectrometry (TIMS) [Edwards et al, 1987]. We show here that this method provides a precision that is appropriate for resolving decadal trends in ocean properties.…”

Section: '1 -1mentioning

confidence: 99%

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U/Th‐dated sclerosponges from the Indonesian Seaway record subsurface adjustments to west Pacific Winds

Moore¹,

Charles²,

Rubenstone³

et al. 2000

Paleoceanography

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Abstract. Stable isotope records from sclerosponges collected at 10-20 m depth in the Indonesian Seaway and Solomon Islands are particularly well suited for reconstructing century-scale trends in ambient temperature variability and the oceanic uptake of fossil fuel carbon. Basal U/Th dates demonstrate that the sclerosponges analyzed are 85-100 years old. Isotopic records from the Indonesian specimens suggest a strong subsurface cooling over the past 20 years that is not manifested in either surface instrumental or shallower coral proxy records. However, analysis of observed subsurface temperatures in Indonesia, observed winds in the west Pacific, and simulated subsurface temperatures from a steady state general circulation model hindcast forced by observed winds combine to suggest that thermocline adjustments could account for at least part of the recent cooling inferred from the Indonesian sclerosponges. If so, the sclerosponge data suggests that, on average, the west Pacific thermocline has shoaled significantly over at least the past 2 decades.

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“…U/Th methods in young corals clearly have the potential to meet these demands [Edwards' et al ,1987]; our results represent the first attempt to apply the method to sclerosponges.…”

Section: Chronology and Resolutionmentioning

confidence: 99%

Section: '1 -1mentioning

confidence: 99%

U/Th‐dated sclerosponges from the Indonesian Seaway record subsurface adjustments to west Pacific Winds

Moore¹,

Charles²,

Rubenstone³

et al. 2000

Paleoceanography

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“…U and Th chemical separations and the mass spectrometry analysis were performed at the U-series chronology lab of Institute of Geology and Geophysics (IGG), Chinese Academy of Sciences. The chemical separation procedures were similar to those described in Edwards et al (1987) and Cheng et al (2013). About 30-300 mg of the powered samples were weighted in an acid-cleaned Teflon beaker, and dissolved first in HNO 3 , then in HF and HClO 4 to ensure that the samples were completely dissolved.…”

Section: Methodsmentioning

confidence: 99%

230Th/238U dating of hydrothermal sulfides from Duanqiao hydrothermal field, Southwest Indian Ridge

Yang

Tao

et al. 2016

Mar Geophys Res

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Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones at the central volcano, at 50°28 0 E in the ultraslow-spreading Southwest Indian Ridge (SWIR). Twenty-eight subsamples from a relict chimney and massive sulfides were dated using the 230 Th/ 238 U method. Four main episodes of hydrothermal activity were determined according to the restricted results: 68. 9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. The periodic character of hydrothermal activity may be related to the heat source provided by the interaction of local magmatism and tectonism. The estimated mean growth rate of the sulfide chimney is \0.02 mm/yr. This study is the first to estimate the growth rate of chimneys in the SWIR. The maximum age of the relict chimney in Duanqiao hydrothermal filed is close to that of the chimneys from Mt. Jourdanne (70 kyrs). The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. The preliminarily estimated reserves of sulfide ores of Duanqiao are approximately 0.5-2.9 million tons.

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“…However, by measuring the abundance of 232 Th in the sample, corrections can be made for any "detrital Th" (e.g. Th derived from other processes aside from purely radioactive decay) that may have originally been incorporated into the mineral (Edwards et al, 1987;Ludwig and Titterington, 1994;Neymark and Paces, 2000;Sharp et al, 2003;Paces et al, 2004;Maher et al, 2007;Fletch et al, 2010).…”

Section: Th-u Geochronologymentioning

confidence: 99%

An Assessment of Late Pleistocene to Middle Holocene Lake Level Fluctuations in Surprise Valley, California

Ibarra¹

2018

Preprint

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Knowledge of Earth’s climate history and sensitivity, combined with modeling past and future climate, are central to informing policy decisions regarding future climate change. The hydrologic response to future warming scenarios due to increased anthropogenic CO2 emissions remains uncertain. Freshwater availability in the arid western United States is projected to decrease in availability as increased agricultural, urban and industrial uses continue to stress supplies. Motivated by the potential for dramatic future hydrologic changes, studies recording the abrupt transitions between different equilibrium states of natural past climate variability shed light on our understanding of the modern climate system.The presence of pluvial lakes in the Basin and Range Province, in the western United States, during the late Pleistocene (40 to 10 ka) indicates far greater moisture availability during the Pleistocene glacials. This study investigates the timing and magnitude of the most recent pluvial lake cycle that filled Surprise Valley, California using geophysical, geochemical and geochronologic tools. Spanning 31.2 to 4.6 ka, this new lake level record places the highest lake level, at 180 meters above present day playa, at 13.9 ± 1.2 ka. This age appears to be nearly synchronous with highstands of Lake Lahontan to the south and the Chewaucan Basin to the north. Additionally, most of the Basin and Range lake highstands, including Lake Surprise, follow peaks in precipitation minus evapotranspiration (P-ET) by 8-10 kyr. By compiling a diverse set of paleoclimate data available for western North America, I found that the timing and geographic distribution of lake highstands is inconsistent with increased precipitation in response to shifting westerly winds, the current model for the genesis of large lakes in western North America. Rather, lakes levels are more strongly correlated with changes in summer insolation, suggesting that lake highstands were likely facilitated by colder temperatures and increased humidity due to the presence of continental ice sheets and increased atmospheric convergence. I compared the constraints from lake and soil-based records to Atmosphere-Ocean General Circulation Model simulations from the Paleoclimate Model Intercomparison Project 2. Based on model-proxy intercomparison, the Atmosphere-Ocean General Circulation Models, the same models used to also assess future climatic changes, poorly predict hydrologic quantities for the Last Glacial Maximum.

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Precise Timing of the Last Interglacial Period from Mass Spectrometric Determination of Thorium-230 in Corals

Cited by 344 publications

References 26 publications

U/Th‐dated sclerosponges from the Indonesian Seaway record subsurface adjustments to west Pacific Winds

U/Th‐dated sclerosponges from the Indonesian Seaway record subsurface adjustments to west Pacific Winds

230Th/238U dating of hydrothermal sulfides from Duanqiao hydrothermal field, Southwest Indian Ridge

An Assessment of Late Pleistocene to Middle Holocene Lake Level Fluctuations in Surprise Valley, California

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