Sentences with phrase «isotope records from»

Four of these eight represent integrations of multiple proxy site records or reconstructions, including some O isotope records from ice cores and documentary information as well tree ring records.

Ono, S., J.L. Eigenbrode, A.A. Pavlov, P. Kharecha, D. Rumble, III, J.F. Kasting, and K.H. Freeman, 2003: New insights into Archean sulfur cycle from mass - independent sulfur isotope records from the Hamersley Basin, Australia.

Variations in tree ring stable isotope records from northern Finland and their possible connection to solar activity, Ogurtsov et al, 02/2010; read more here.

Variations in tree ring stable isotope records from northern Finland and their possible connection to solar activity, Maxim Ogurtsov, 02/2011, Journal of Atmospheric and Solar - Terrestrial Physics, Volume 73, Issues 2 — 3, pp. 383 — 387

Climatic signals in multiple highly resolved stable isotope records from Greenland.

The isotope records from WAIS Divide and US ITASE: climate in West Antarctica over the past two millennia (Invited).

Evidence from carbon isotope records from both soil carbonates [18]--[20] and biomarkers (n - alkanes) extracted from deep - sea sediments [21] provide clear evidence of a progressive vegetation shift from C3 (∼ trees and shrubs) to C4 (∼ tropical grasses) plants during the Plio - Pleistocene.

New evidence of Holocene climate and atmospheric circulation variability, inferred from lacustrine stable isotope records from Gotland, southern Sweden Francesco Muschitiello, Dan Hammarlund, Barbara Wohlfarth

Evidence for approximately contemporaneous global cooling in sediments that do contain YTT glass shards has been found in marine core oxygen isotope records from the South China Sea (3), as have terrestrial carbon isotope and pollen records from Northern India and Bengal (23).

J. You / Science; Data: «Climatic signals in multiple highly resolved stable isotope records from Greenland,» Vinther et al, 3 November 2009; «Norse Greenland settlement,» Dugmore et al., 2007; «Human diet and subsistence patterns in Norse Greenland AD c. 980 — AD c. 1450,» Arneborg et al. 2012

The new sea - level record was then used in combination with existing deep - sea oxygen isotope records from the open ocean, to work out deep - sea temperature changes.

A high resolution stable isotope record from central West Antarctica covering the last 62,000 years.

http://www.agu.org/pubs/crossref/2002/2000PA000571.shtml On the 1470 - year pacing of Dansgaard - Oeschger warm events The oxygen isotope record from the Greenland Ice Sheet Project 2 (GISP2) ice core was reanalyzed in the frequency and time domains.

Global solar irradiance reconstruction [48 — 50] and ice - core based sulfate (SO4) influx in the Northern Hemisphere [51] from volcanic activity (a); mean annual temperature (MAT) reconstructions for the Northern Hemisphere [52], North America [29], and the American Southwest * expressed as anomalies based on 1961 — 1990 temperature averages (b); changes in ENSO - related variability based on El Junco diatom record [41], oxygen isotopes records from Palmyra [42], and the unified ENSO proxy [UEP; 23](c); changes in PDSI variability for the American Southwest (d), and changes in winter precipitation variability as simulated by CESM model ensembles 2 to 5 [43].

Jones / Mann showed (and Mann / Jones used in their reconstruction) an isotope record from Law Dome that is probably O18 (they say «oxygen isotopes»).

Not exact matches

In Greenland lead isotopes in ice cores reveal a record of lead pollution from Roman smelting in Spain some 2,000 years ago.

The team used records of oxygen isotope ratios (which provide a record of ancient water temperature) from microscopic plankton fossils recovered from the Mediterranean Sea, spanning the last 5.3 million years.

That could explain two other anomalies from the era's geologic record, Lenton says: the large amounts of organic - rich shale that were deposited as nearshore sediments and the unusually high proportion of carbon - 13 isotopes in the rocks.

Their results overcome a basic problem of trying to discern the deep history of ice from bedrock: every time an ice sheet retreats and then grows back, it scours away the bedrock and the isotope record of its own past.

The researchers compared the lead isotopes in their sediment samples with those found in preserved Roman piping to create a historical record of lead pollution flowing from the Roman capital.

From 1990 to 2010, the nitrogen isotope record indicates that oxygen content steadily decreased in the area, as expected.

By studying the variations of uranium isotopes recorded in carbonates, the team was able to infer global anoxia occurring throughout the ocean using samples from a single outcrop.

Eggshells contain carbon, which comes from the birds» diets, and because different plants have different ratios of carbon isotopes, the shells can be used as a rough record of what birds ate.

The paleoclimate data, which included mainly changes in the oxygen isotopes of the calcium carbonate deposits, were then compared to similar records from other caves, ice cores, and sediment records as well as model predictions for water availability in the Middle East and west central Asia today and into the future.

For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age.

According to the researchers, this isotope formed as a result of cosmic ray particles or protons hitting out atmosphere, emanating from a minor superflare, around 10 — 100 times larger than any solar flare in recorded history.

Based on the temperature minimum recorded from the early Late Oxfordian of Kachchh, it was suggested that the widening of the Trans - Gondwanan Seaway may have led to increased upwelling in the Malagasy Gulf and to a cooling recorded in the oxygen isotopes of belemnites and other marine invertebrates from Kachchh [38].

We only have direct observations of total solar irradiance (TSI) since the beginning of the satellite era and substantial evidence for variations in the level of solar activity (from cosmogenic isotopes or sunspot records) in the past.

The record tells the story of the sudden release of an isotopically light source of carbon, triggering a fast warming in the deep sea of about 5 degrees C. Both the carbon isotope signal and the temperature (inferred from oxygen isotopes) then relaxed back toward their initial values in about 100,000 years.

The most recent paper I read from this past Spring does suggests that the CO2 levels have varied more; however, there is not sufficient geologic evidence that I have seen (Even with the examination of the foraminifera O2 isotope record.

Here, we present a record of Holocene glacial ice discharge, derived from the oxygen isotope composition of marine diatoms from Palmer Deep along the west Antarctic Peninsula continental margin.

The team measured trace elements and stable isotopes in stalagmites from the Indonesian island of Flores and used them to reconstruct ancient rainfall, comparing them to records from East Asia and the central - eastern equatorial Pacific.

The Wright and Schaller study generated very detailed records of variations in the isotopes of carbon and oxygen through the PETM recorded by carbonates in clay sediments from New Jersey, USA.

Individual model parameterizations were constrained by paleontological data, and the overall modeled relationship between global temperature and sea level matched well against records from four previous warm periods: preindustrial, the last interglacial, marine isotope stage 11, and the mid-Pliocene.

These physical temperature measurements help calibrate the temperature record scientists obtain from oxygen isotopes.

''... worked with two sediment cores they extracted from the seabed of the eastern Norwegian Sea, developing a 1000 - year proxy temperature record «based on measurements of δ18O in Neogloboquadrina pachyderma, a planktonic foraminifer that calcifies at relatively shallow depths within the Atlantic waters of the eastern Norwegian Sea during late summer,» which they compared with the temporal histories of various proxies of concomitant solar activity... This work revealed, as the seven scientists describe it, that «the lowest isotope values (highest temperatures) of the last millennium are seen ~ 1100 - 1300 A.D., during the Medieval Climate Anomaly, and again after ~ 1950 A.D.» In between these two warm intervals, of course, were the colder temperatures of the Little Ice Age, when oscillatory thermal minima occurred at the times of the Dalton, Maunder, Sporer and Wolf solar minima, such that the δ18O proxy record of near - surface water temperature was found to be «robustly and near - synchronously correlated with various proxies of solar variability spanning the last millennium,» with decade - to century - scale temperature variability of 1 to 2 °C magnitude.»

Just how large this methane rise must have been is not yet fully reconstructed from the carbon isotope record.

«The solar and volcanic forcings we use are derived from reconstructions based on proxy data and are therefore also subject to considerable uncertainties, although recent explosive volcanic eruptions are likely to have cooled climate, and independent records of solar activity levels inferred from the cosmogenic isotope 10Be (43) and geomagnetic records (44) provide support to reconstructions (22, 45) that show generally increasing solar activity during the 20th century (12).»

Now in a Climate of the Past paper, Seltzer et al. present a new record of oxygen isotopes in atmospheric O2 derived from two Antarctic ice cores.

Stable carbon isotope ratios from tree rings record changes in the internal concentration of carbon dioxide and, in the northern Boreal zone, are regarded as a proxy for photosynthetic rate, and therefore summer sunshine.

Early TRL projects focused on establishing long tree - ring records from temperature - sensitive boreal forest locations in North American for studies of global change, using dendrochronologically dated wood, to investigate the value of stable isotope ratios in cellulose as paleo - thermometers and developing the necessary computer software for processing the data.

Prior to direct telescopic measurements of sunspots, which commenced around 1610, knowledge of solar activity is inferred indirectly from the 14C and 10Be cosmogenic isotope record in tree rings and ice cores, respectively, which exhibit solar related cycles near 90, 200 and 2,300 years.

«Recently, Abreu et al. (2012, hereafter A2012) made a new attempt in this direction by comparing periodicities detected in the records of cosmogenic isotopes 10Be and 14C (or quantities derived from them) as proxies for solar activity in the past 9400 years with those of the torque exerted on a thin shell of an ellipsoidally deformed Sun.»

A study by Thomas, Dennis et al 2009 [8] derived a high resolution temperature proxy record from oxygen isotope ratios from the ice core.

«The surface temperature changes for the last 4000 years in northern inland Iberia (an area particularly sensitive to climate change) are determined by a high resolution study of carbon stable isotope records of stalagmites from three caves (Kaite, Cueva del Cobre, and Cueva Mayor) separated several 10 s km away in N Spain.

c) Average sunspot number prediction by a low - frequency modulation model (dotted curve) based on frequency analysis from sunspot and cosmogenic isotope records, compared to the average sunspot number since 1750 (continuous curve).

Note that regional proxies, such as the oxygen - isotope temperature reconstructions from the Greenland Ice Core Project that record Dansgaard - Oeschger events, often indicate faster regional rates of climate change than the overall global average for glacial - interglacial transitions, just as today warming is more pronounced in Arctic regions than in equatorial regions (Barnosky et al., 2003; Diffenbaugh and Field, 2013).

The modulation potential used in the calculations is based on the composite of data determined from the cosmogenic isotope records of 10Be and a neutron monitor.

Much longer records of solar behavior come from atomic isotopes that are produced in our atmosphere by the impact of galactic cosmic rays, whose rate of incidence at the Earth is affected by conditions on the Sun.

We use isotope data from Zachos et al. [4], which are improved over data used in our earlier study [5], and we improve our prescription for separating the effects of deep ocean temperature and ice volume in the oxygen isotope record as well as our prescription for relating deep ocean temperature to surface air temperature.