Sentences with phrase «ocean sediment cores»

To reach their findings, the team examined ocean sediment cores and found that over the past 100,000 years, at least 8 «pulses» of iron have penetrated the eastern equatorial Pacific.

I was teased by my climate modeller colleagues about so much hands - on work with climate proxies (e.g., tree rings and ocean sediment cores) and was considered askance by my climate proxy colleagues.

There are now several alternative proxy measures of ancient climate change, but the δ18O data (figure 1a) of Zachos et al. [4], a conglomerate of the global ocean sediment cores, is well suited for our purpose as it covers the Cenozoic era with good temporal resolution.

Proxy records of climate, like those derived from ice cores and ocean sediment cores, track the big - picture changes well but can't provide the same level of local detail we have for the past century.

The principal dataset we use is the temporal variation of the oxygen isotope ratio (δ18O relative to δ16O; figure 1a right - hand scale) in the shells of deep - ocean - dwelling microscopic shelled animals (foraminifera) in a near - global compilation of ocean sediment cores [4].

Climate forcings due to past changes in GHGs and surface albedo can be computed for the past 800000 years using data from polar ice cores and ocean sediment cores.

report that ocean sediment cores containing an «undisturbed history of the past» have been analyzed for variations in PP over timescales that include the Little Ice Age... they determined that during the LIA the ocean off Peru had «low PP, diatoms and fish,» but that «at the end of the LIA, this condition changed abruptly to the low subsurface oxygen, eutrophic upwelling ecosystem that today produces more fish than any region of the world's oceans... write that «in coastal environments, PP, diatoms and fish and their associated predators are predicted to decrease and the microbial food web to increase under global warming scenarios,» citing Ito et al..

The research team, which included Jeremy Shakun of Harvard and Alan Mix of OSU, primarily used fossils from ocean sediment cores and terrestrial archives to reconstruct the temperature history.

The pulses of growth match cooling periods documented in ocean sediment cores and in the continuous cores from Iceland and Baffin Island, suggesting that glaciers have responded in sync across the North Atlantic for at least the past 4,000 years, the authors write.

For instance, here's the data for delta - oxygen - 18 from a stack of 57 ocean sediment cores, which is considered an excellent proxy for global ice volume, known as the «LR04 stack» (from Lisiecki, L.E., & Raymo, M.E. 2005.

In this paper, the authors reconstruct North Atlantic water temperature over the last millennium using oxygen isotopes from ocean sediment cores on the Canadian east coast.

Indeed, its a very important paper in the history of climate, linking observed cycles in ocean sediment cores to orbital forcing periodicities.

The chemical evidence mainly consists of variations in the ratios of isotopes in fossils present in sediments and sedimentary rocks and ocean sediment cores.

Despite the difficulties, analyses of ice core and ocean sediment cores has shown periods of glacials and interglacials over the past few million years.

Hence the continental crust phenomena are accepted as good evidence of earlier ice ages when they are found in layers created much earlier than the time range for which ice cores and ocean sediment cores are available.

The dates on two other ocean sediment cores (Stott et al 2004 — # 14 and # 15) are on the correct scale thankfully, but are still marginal in terms of resolution (29 and 44 years respectively, but effectively longer still due to bioturbation of the sediments).

Indeed, its a very important paper in the history of climate, linking observed cycles in ocean sediment cores to orbital forcing periodicities.

High - resolution ocean sediment cores can sometimes be found that fit this, as can some cave (speleothem) records and pollen records etc..

The pulses of growth match cooling periods documented in ocean sediment cores and in the continuous cores from Iceland and Baffin Island, suggesting that glaciers have responded in sync across the North Atlantic for at least the past 4,000 years, the authors write.

Ranging from the magnesium levels in microscopic seashells pulled from ocean sediment cores to pollen counts in layers of muck from lakebeds, the proxies delivered thousands of temperature readings over the period.

Climate scientists find the last glacial period interesting because ice cores in Greenland and ocean sediment cores have shown that during this period there were sharp shifts in global temperatures.

The researchers studied temperature measurements over the last 150 years, ice core data from Greenland from the interglacial period 12,000 years ago, for the ice age 120,000 years ago, ice core data from Antarctica, which goes back 800,000 years, as well as data from ocean sediment cores going back 5 million years.

Not even a massive outpouring of carbon 56 million years ago (recorded in this ocean sediment core as the 25 - centimeter - long red band) comes close, a new study suggests.

The MD99 - 2275 core offshore Iceland is a very high - resolution ocean sediment core, results of which over the past millennium have been discussed here from time to time.

Not exact matches

The foundation of the research involved tracking the changes in ocean circulation in new detail by studying three sediment cores extracted from the seafloor of the Gulf of Mexico in 2010 during a scientific cruise.

The aim of my PhD is to use the distribution of diatom species preserved in sediment cores across the Scotia Sea to reconstruct the position of major ocean boundaries and water masses through time.

And so a team of marine sediment experts has set up shop on the Nathaniel B. Palmer, hoping to sink great hollow cores deep into the ocean off Antarctica.

The team, led by Dr Kira Rehfeld and Dr Thomas Laepple, compared the Greenland data with that from sediments collected in several ocean regions around the globe, as well as from ice - core samples gathered in the Antarctic.

Comparing layers in the ice - core samples and ocean sediments has allowed researchers to deduce e.g. how the average temperature on Earth has changed over time, and also how great the variability was.

The researchers analyzed a marine sediment core collected off the coast of the Eastern Cape of South Africa, close to where the Great Kei River meets the ocean.

Up until now, instrumental observations of the oceans have only spanned the last 100 years or so, whilst reconstructions using marine sediment cores come with significant age uncertainties.

Finds like that, along with sediment cores and ice cores that show how the amount of methane in the atmosphere and ocean has fluctuated dramatically in the past, have led to a slew of «methane burp» theories.

For 2 months in 2013, the JOIDES Resolution, the ship for the International Ocean Discovery Program, drilled into the ocean floor sediments, retrieving cores of mud and rock that were then dOcean Discovery Program, drilled into the ocean floor sediments, retrieving cores of mud and rock that were then docean floor sediments, retrieving cores of mud and rock that were then dated.

«Thanks to the sediment core data, we have clear evidence that, during the last interglacial roughly 125,000 years ago, the central Arctic Ocean was still covered with sea ice during the summer.

Analysing new data from marine sediment cores taken from the deep South Atlantic, between the southern tip of South America and the southern tip of Africa, the researchers discovered that during the last ice age, deep ocean currents in the South Atlantic varied essentially in unison with Greenland ice - core temperatures.

Earlier this year, Berke boarded a research vessel in the Indian Ocean with 29 international scientists to retrieve sediment cores off the coast of southern Africa.

In 2014, they embarked on an ocean voyage to the central equatorial Pacific Ocean, where they drilled into the sediment bed and collected six cocean voyage to the central equatorial Pacific Ocean, where they drilled into the sediment bed and collected six cOcean, where they drilled into the sediment bed and collected six cores.

Using hand - driven cores, augers, and shovels to reveal the sediments blanketing a lowland facing the Pacific Ocean, and using radiocarbon dating to estimate the times of sand sheet deposition, scientists established a geologic history of past large tsunamis.

Christina Ravelo led IODP Expedition 323 to the Bering Sea in 2009 and collected sediment cores that preserve records of regional climate and ocean circulation covering the past 1.2 million years.

Now, new evidence from a marine sediment core from the deep Pacific points to warmer ocean waters around Antarctica (in sync with the Milankovitch cycle)-- not greenhouse gases — as the culprit behind the thawing of the last ice age.

Paleoclimate: I don't know for sure, but this record is too long (1 million years) to be an ice core, so I'm guessing it's a stacked sediment core, showing delta - O18 from ocean foraminifera.

However, foraminifera data are limited and difficult to obtain by deep - sea sediment coring, and the shells are not perfect proxies for ocean conditions.

Sediment cores from every major ocean and sea are archived here.

The researchers traced the Horn of Africa's climate 200,000 years into the past by analyzing a core of ocean sediment taken in the western end of the Gulf of Aden.

About 104 stages of these cold and temperate cycles have been recognised in deep ocean marine sediment cores (Figure 1)[1].

Ice core data from Antarctic from ocean sediments show 8 episodes of very large ice flux — largest 14,600 years ago, meltwater pulse 1a — 1 - 3 meters sea level rise per century for several centuries.

The team also correlated their findings with other studies of California climate history, and for the first time, cross-referenced these with histories of the Pacific Ocean's temperature taken from marine sediment cores and other sources.

Donnelly's team examined cores of sediment sampled from two of the salt pond's deepest points, searching for layers that were deposited when storms violently washed ocean sand into the 65 - acre waterway.

Paleoclimatology data are derived from natural sources such as tree rings, ice cores, corals, and ocean and lake sediments.

Suppl., HR: 1340h AN: OS53B - 1101 Holocene Paleoceanography of the Chukchi Sea / Alaskan Margin, Western Arctic Ocean «A multi-proxy approach to the analysis of deep - sea sediment cores has been used to investigate paleoceanographical changes in the western Arctic.»