Sentences with phrase «oxygen isotope records»

The continental glaciations of the Pleistocene left signatures on the landscape in the form of glacial deposits and landforms; however, the best knowledge of the magnitude and timing of the various glacial and interglacial periods comes from oxygen isotope records in ocean sediments.

A negative trend is also seen in oxygen isotope records in Greenland ice cores (NGRIP - members 2004), which implies that the proxy records from northern Sweden display a general feature of Holocene climate in the North Atlantic region, possibly linked to orbital forcing of summer insolation.

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).

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.

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].

HS12 uses the oxygen isotope record in ocean sediments Zachos et al. (2008) to estimate past changes of sea level and ocean temperature, and thus obtain a largely empirical estimate of climate sensitivity.

We use the rich climate history of the Cenozoic era in the oxygen isotope record of ocean sediments to explore the relation of climate change with sea level and atmospheric CO2, inferring climate sensitivity empirically.

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.

Not exact matches

The ratio of strontium to calcium in a given layer of coral reef — as well as the amount of a heavier isotope of oxygen in the carbonate itself — reflect the temperature in this historical record, but the isotopic information also reveals rainfall.

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.

By carefully micro-sampling each shell along its direction of growth and analyzing for stable carbon and oxygen isotopes and trace elements, the team reconstructed a record of seasonal variation during the lifetimes of the organisms.

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

In the past decade, paleoclimatologists have reconstructed a record of climate change over the last millennium by consulting historical documents and examining indicators of temperature change like tree rings, as well as oxygen isotopes in ice cores and coral skeletons.

Whenever they found large dips in the oxygen - 18 isotope, they found a corresponding historical record of a hurricane.

The oxygen and carbon isotopes present in the remains provided them with records of temperature and humidity levels during the period.

So when water vapor that has cycled through the Martian atmosphere condenses into the Martian soil, it can interact with and exchange oxygen isotopes with zircons in the soil, effectively writing a climate record into the rocks.

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.

In both cases the climate records are based on oxygen isotope measurements on datable layers of ice or stalagmite cave deposition.

There are also a number of paleoclimatic recorders of oxygen isotopes, including lake / ocean records, speleothems (in caves), corals, ice cores, etc..

First, I do think that there is a lot of work to be done in the interpretation of oxygen / hydrogen isotope values obtained at a site, and there's still plenty of disagreement in the paleo - community on how to best connect the isotopic signal in a record with climate.

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 analyzed stable carbon and oxygen isotopes (δ13C, δ18O) of decade - old California mussel shells (Mytilus californianus) in the context of an instrumental seawater record of the same length.

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.

There are also a number of paleoclimatic recorders of oxygen isotopes, including lake / ocean records, speleothems (in caves), corals, ice cores, etc..

First, I do think that there is a lot of work to be done in the interpretation of oxygen / hydrogen isotope values obtained at a site, and there's still plenty of disagreement in the paleo - community on how to best connect the isotopic signal in a record with climate.

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.

«Oxygen and Carbon Isotope Record of East Pacific Core V19 - 30: Implications for the Formation of Deep Water in the Late Pleistocene North Atlantic.»

Measurements of coral Sr / Ca and oxygen 18 isotopes at 5 - year sampling increments for five of the fossil corals (310 annual growth increments) have yielded a semi-continuous record spanning the 8.2 ka event.

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.

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

Statistical analysis of the carbon and oxygen stable isotope recordsr eveals variations in the periods around 100, 11 and 3 years.A century scale connection between the 13C / 12C record and solar activity is most evident.»

The fact that the Little Ice Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.

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.

The stratigraphic framework and related age models of the four sediment cores used in this study, are based on oxygen isotope stratigraphy, 10Be stratigraphy, paleomagnetostratigraphy, biostratigraphy, lithostratigraphy, and / or magnetic susceptibility records (Supplementary Figs. 2 — 5).

Using modern spatiotemporal records of oxygen production and oxygen isotopes in terrestrial precipitation, the authors demonstrate that their proposed relationship is robust over the modern seasonal cycle.

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

Broecker later remarked that the relatively smooth temperature record of oxygen isotopes in deep - sea sediments «tended to lull scientists into concluding that the Earth's climate responds gradually when pushed.»

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).

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

Oxygen isotope and palaeotemperature records from six Greenland ice - core stations temperatures during the Medieval Warm Period (~ AD 800-1100) were about 1 °C warmer than those of the Current Warm Period.

Despite these successes in linking variations in greenhouse gas concentrations to climate change in the geologic past, the oxygen isotope palaeotemperature record from 600 Myr ago to the present displays notable intervals for which inferred temperatures and pCO2 levels are not correlated1.

A similar negative trend is seen in most other Holocene paleoclimate records from northern Sweden, e.g. changes in tree - limit (Karlén 1976; Kullman 1995); pollen (Barnekow 1999); chironomids (Larocque and Bigler 2004); oxygen - isotopes in lacustrine biogenic silica (Shemesh et al. 2001) and in lacustrine carbonates (Hammarlund et al. 2002).

Looking at the isotopic record from the PETM, scientists see both carbon and oxygen isotope ratios spiking in exactly the way we expect to see in the Anthropocene record.