نتایج جستجو برای: paleotemperature
تعداد نتایج: 224 فیلتر نتایج به سال:
[1] Noble gas paleoclimate reconstructions from noble gas concentrations in groundwater have the promise of providing absolute paleotemperature information, but difficulties in modeling measured noble gas concentrations with simple models have led to a number of competing noble gas temperature (NGT) schemes being developed. These different models make different assumptions about the size and na...
Temperature is one of the most important climate factors that can regulate the activity and growth of organisms. However, it is so far unclear how temperature influences the abundance and community composition of magnetotactic bacteria (MTB) that mineralize intracellular magnetite and/or greigite magnetosomes and play significant roles in the global iron cycling and sediment magnetization. To a...
Gas ratios in air withdrawn from polar firn (snowpack) show systematic enrichments of Ne/N2, O2/N2 and Ar/N2, in the firn–ice transition region where bubbles are closing off. Air from the bubbles in polar ice is correspondingly depleted in these ratios, after accounting for gravitational effects. Gas in the bubbles becomes fractionated during the process of bubble close-off and fractionation ma...
Stable oxygen isotopes from fossils, both vertebrate and invertebrate, or inorganic sedimentary minerals frequently have been used to make interpretations about ancient global climates. Oxygen isotope values measured from terrestrial vertebrates or sedimentary carbonates provide information about paleotemperature and amounts of precipitation at a particular site. In general, these inferences ar...
[1] The Subtropical Front (STF) marking the northern boundary of the Southern Ocean has a steep gradient in sea surface temperature (SST) of approximately 4 C over 0.5 of latitude. Presently, in the region south of Tasmania, the STF lies nominally at 47 S in the summer and 45 S in the winter. We present here SST reconstructions in a latitudinal transect of cores across the South Tasman Rise, so...
Many ecosystem processes that influence Earth system feedbacks – vegetation growth, water and nutrient cycling, disturbance regimes – are strongly influenced by multidecadalto millennial-scale climate variations that cannot be directly observed. Paleoclimate records provide information about these variations, forming the basis of our understanding and modeling of them. Fossil pollen records are...
The westernmost Mediterranean is one of the most sensitive areas to global climate change and high sedimentation rates allow recording frequency variability. We present a high-resolution paleotemperature reconstruction over last 35 kyr using, for first time, four independent organic sea surface temperature (SST) proxies (UK'37, TEXH86, RI-OH' LDI) based on alkenones, (hydroxy) isoprenoid GDGTs,...
Abstract. Over the last decades, sea surface temperature (SST) reconstructions based on Mg∕Ca of foraminiferal calcite have frequently been used in combination with δ18O signal from same material to provide estimates water (δ18Ow), a proxy for global ice volume and salinity (SSS). However, because error propagation one step next, better calibrations are required increase accuracy robustness exi...
Abstract. Late Miocene to Pliocene sediments from the NW Australian shelf, drilled by International Ocean Discovery Program (IODP) Expedition 356, provide unique records of paleoclimatic variations under warmer-than-present conditions. During period 6 3.5 Ma, area was dominated warm, tropical waters supplied an intensified, uninterrupted Indonesian throughflow and characterised prevailing humid...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید