pinecone/core-2020-05-10-deduplication huggingface dataset:
Asynchroneity of maximum glacier advances in the central Spanish Pyrenees

31 páginas, 7 figuras, 1 tablaThe deglaciation history of the Escarra and Lana Mayor glaciers (Upper\ud
Gállego valley, Central Spanish Pyrenees) was reconstructed on the basis of detailed\ud
geomorphological studies of glacier deposits, sedimentological and palynological\ud
analyses of glacial lakes sediments and an AMS chronology based on minimum ages\ud
from glacial lake deposits. The maximum extent of the Pyrenean glaciers during the last\ud
glaciation was before 30,000 years B.P. and predated the maximum advances of the\ud
Scandinavian Ice Sheet and some Alpine glaciers. A later advance occurred during the\ud
coldest period (around 20,000 years B.P.) synchronous with the maximum global ice\ud
extent, but in the Pyrenees it was less extensive than the previous one. Later, there were\ud
minor advances followed by a stage of debris-covered glaciers and a phase of moraine\ud
formation near cirque backwalls. The deglaciation chronology of the Upper Gállego\ud
valley provides more examples of the general asynchroneity between mountain and\ud
continental glaciers. The asynchroneity of maximum advances may be explained by\ud
different regional responses to climatic forcing and by the southern latitudes of the\ud
Pyrenees.This work was part of the Project "Isotope sedimentology of 40 ka time-series\ud
from Iberian sites as a test for abrupt arid/humid switching within the Mediterranean\ud
climate zone" (EAR 941-8657), funded by the National Science Foundation, USA, and\ud
the Project "Arid periods in the Mediterranean area since the Last Glacial Maximum"\ud
(REN2000-1136/CLI), funded by the Spanish “Comisión Interministerial de Ciencia y\ud
Tecnología”. The authors thank Dr. Colin Ballantyne, Dr. Valérie Andrieu-Ponel and\ud
Dr. María Fernanda Sánchez-Goñi for their criticisms and suggestions that improved\ud
the manuscript.Peer reviewe
Evidence for a mid-Pleistocene change of ice-drift pattern in the Nordic seas

Sediment proxy records from a continuous, 1.5 million year long deep-sea sediment core from a site in the western Norwegian Sea were used to obtain new insights into the nature of palaeoceanographic change in the northern North Atlantic (Nordic seas) during the climatic shift of the Mid-Pleistocene Revolution (MPR). Red-green sediment colour and magnetic susceptibility records both reveal significant differences in their mean values when comparing the intervals older than 700 000 yr (700 ka) with those from the past 500 kyr. The timing and duration of these changes indicates that the MPR in the Nordic seas is characterised by a gradual transition lasting about 200 kyr. Together with further sedimentological evidence this suggests that the mid-Pleistocene climate shift was accompanied by a general change in ice-drift pattern. It is further proposed that prior to the onset of the major late Pleistocene glaciations in the Northern Hemisphere a significant proportion of the ice in the eastern Nordic seas originated from a southern provenance, whereas later it dominantly came from the surrounding landmasses
Lake stratigraphy implies an 80 000 yr delayed melting of buried dead ice in northern Russia

Sediment cores from lakes Kormovoye and Oshkoty in the glaciated region of the
Pechora Lowland, northern Russia, reveal sediment gravity flow deposits overlain by lacustrine
mud and gyttja. The sediments were deposited mainly during melting of buried glacier ice beneath
the lakes. In Lake Kormovoye, differential melting of dead ice caused the lake bottom to subside at
different places at different times, resulting in sedimentation and erosion occurring only some few
metres apart and at shifting locations, as further melting caused inversion of the lake bottom. Basal
radiocarbon dates from the two lakes, ranging between 13 and 9 ka, match with basal dates from
other lakes in the Pechora Lowland as well as melting of ice-wedges. This indicates that buried glacier
ice has survived for ca. 80 000 years from the last glaciation of this area at 90 ka until about 13 ka
when a warmer climate caused melting of permafrost and buried glacier ice, forming numerous lakes
and a fresh-looking glacial landscape
Climate change in lowland Central America during the late deglacial and early Holocene

The transition from arid glacial to moist early Holocene conditions represented a profound change in northern lowland Neotropical climate. Here we report a detailed record of changes in moisture availability during the latter part of this transition (11 250 to 7500 cal. yr BP) inferred from sediment cores retrieved in Lake Pete´n Itza´, northern Guatemala. Pollen assemblages demonstrate\ud
that a mesic forest had been largely established by 11 250 cal. yr BP, but sediment properties indicate that lake level was more than 35m below modern stage. From 11 250 to 10 350 cal. yr BP,during the Preboreal period, lithologic changes in sediments from deep-water cores (>50m below\ud
modern water level) indicate several wet–dry cycles that suggest distinct changes in effective moisture. Four dry events (designated PBE1-4) occurred centred at 11 200, 10 900, 10 700 and 10 400 cal. yr BP and correlate with similar variability observed in the Cariaco Basin titanium record and glacial meltwater pulses into the Gulf of Mexico. After 10 350 cal. yr BP, multiple sediment\ud
proxies suggest a shift to a more persistently moist early Holocene climate. Comparison of results from Lake Pete´n Itza´ with other records from the circum-Caribbean demonstrates a coherent climate response during the entire span of our record. Furthermore, lowland Neotropical climate during the late deglacial and early Holocene period appears to be tightly linked to climate change in the highlatitude North Atlantic. We speculate that the observed changes in lowland Neotropical precipitation were related to the intensity of the annual cycle and associated displacements in the mean latitudinal position of the Intertropical Convergence Zone and Azores–Bermuda high-pressure system. This mechanism operated on millennial-to-submillennial timescales and may have responded to changes in solar radiation, glacial meltwater, North Atlantic sea ice, and the Atlantic meridional overturning\ud
circulatio
Raman spectroscopic study of the vivianite arsenate minerals

The molecular structures of the vivianite-type arsenate minerals were studied using a combination of Raman and infrared spectroscopy. The Raman spectra of the hydroxyl-stretching regions are complex with overlapping bands at 3419, 3209, 3185 and 3010 cm-1. This complexity is reflected in the water HOH bending modes with strong infrared bands in the 1660-1685 cm-1 region indicating strong hydrogen bonding to arsenate anions in adjacent layers. The Raman arsenate AsO stretching region shows strong similarity between the vivianite arsenate minerals. In the infrared spectra complexity exists with multiple antisymmetric stretching vibrations observed, indicating a reduction of symmetry. Strong infrared bands around 700 and 560 cm-1 are attributed to librational modes of water. Vibrational spectra enable the structure of the minerals to be determined and, whilst similarities exist in the spectral patterns, sufficient differences exist to determine the identification of the minerals. In particular, Raman spectroscopy assists in the identification of the complex isomorphous substitution in these vivianite arsenate minerals
Raman spectroscopy of some natural hydrotalcites with sulphate and carbonate in the interlayer

The structures of a series of nickel and magnesium based hydrotalcites have been explored using Raman microscopy.  These natural hydrotalcites are based upon sulphate or carbonate being the counter anion in the interlayer.  Variation in the position of the sulphate stretching vibrations occurs and is mineral dependent.  Raman spectroscopy shows a reduction in the symmetry of both sulphate and carbonate, which leads to the conclusion that the anions are bonded to the brucite-like hydroxyl surface and to the water in the interlayer.  Water bending modes are identified in both the Raman and infrared spectra at positions greater than 1630 cm-1, indicating the water is strongly hydrogen bonded to both the interlayer anions and the hydrotalcite surface
Raman spectroscopy of natural oxalates at 298 and 77 K

A comparative study of a suite of natural oxalates including weddellite, whewellite, moolooite, humboldtine, glushinskite, natroxalate and oxammite was undertaken using Raman spectroscopy at 298 and 77 K. Oxalates are found as films on host rocks as a result of heavy metal expulsion by primitive plants such as lichens and fungi. The minerals are characterized by the Raman position of the CO stretching vibration, which is cation sensitive. The band is observed at 1468 cm-1 for weddellite, 1464 cm-1 for whewellite, 1489 cm-1 for moolooite, 1489 cm-1 for humboldtine, 1471 cm-1 for glushinskite, 1456 cm-1 for natroxalate and 1473 cm-1 for oxammite. Except for oxammite, the infrared and Raman spectra are mutually exclusive, indicating that the minerals are bidentate and planar. Significant differences are observed in the CC stretching region and in the OCO bending region centred upon 910 and 860 cm-1, respectively. The significance of this work rests with the ability of Raman spectroscopy to identify oxalates which often occur as a film on a host rock. As such, Raman spectroscopy has the potential to identify the existence or pre-existence of life forms on planets such as Mars
Raman spectroscopy of the arsenates and sulphates of the tsumcorite mineral group

The structure of a selection of arsenate and sulphate based minerals of the\ud
tsumcorite group has been studied by the combination of Raman and infrared\ud
spectroscopy. A comparison is made with the sulphate bearing mineral natrochalcite.\ud
Isomorphic substitution of sulphate for arsenate is observed for gartrellite and\ud
thometzekite. The position of the hydroxyl and water stretching vibrations are related\ud
to the strength of the hydrogen bond formed between the OH unit and the AsO4 anion.\ud
Estimates of the hydrogen bond distances are calculkated using a Libowitzky type\ud
function. Characteristic Raman spectra of the minerals enable the assignment of the\ud
bands to specific vibrational modes
Raman microscopy of selected chromate minerals

A series of related chromate bearing minerals including crocoite,\ud
phoenicocroite, hemihedrite, iranite, macquartite, fornacite and vauquelinite have\ud
been analysed by Raman microscopy. These minerals are closely related and often\ud
have related paragenesis. Raman microscopy enables the selection of individual\ud
crystals of these minerals for Raman spectroscopic analysis. This is of importance as\ud
often the crystals are found adjacent to each other in the same matrix through\ud
paragenetic relationships. The Raman spectrum of crocoite shows three bands in the\ud
CrO4 stretching region at 856, 841 and 825 cm-1, phoenicocroite at 856, 848, 839 and\ud
826 cm-1, hemihedrite at 847, 837 and 824 cm-1, iranite bands at 865, 846 and 818\ud
cm-1, macquartite at 857, 840 and 814 cm-1. The Raman spectra of fornacite and\ud
vauquelinite are complicated by the presence or AsO4 and PO4 units in the structure\ud
and often the spectra are broad and vary with chemical composition. A comparison of\ud
the spectra of these minerals is made with that of the hexavalent chromate mineral\ud
edoylerite. Raman microscopy is a powerful and underutilized technique in terms of\ud
mineralogy for the study of closely related minerals such as these chromate minerals
Single-crystal Raman study of erythrite, Co3(AsO4)2.8H2O

Single crystal Raman and infrared spectra of natural and synthetic erythrite Co3(AsO4)2.8H2O are reported, and compared to the spectra polycrystalline, synthetic annabergite (Ni3(AsO4)2.8H2O) and hörnesite (Mg3(AsO4)2.8H2O). Factor group analysis and single crystal considerations have been used to interpret the experimental data. The Raman spectra of erythrite reveal ν1 arsenate stretching vibration at 850 \ud
cm-1 (Ag) with the corresponding infrared band at 821 cm-1 (Bu).  The ν3 antisymmetric vibration is split into three components, observed at 796 (Ag), 788 (Ag) and 803 (Bg) cm-1. The ν2 symmetric bending modes are observed at 375 (Ag) and 385 (Bg) cm-1. The ν4 bending modes are predicted to split into three bands which are observed at 441 (Ag), 446 (Bg)  and 457 (Ag) cm-1. Lattice vibrations are found at 112 (Ag), 124 (Bg), 145(Ag), 157 (Bg), 165 (Ag), 179 (Ag), 189 (Ag), 191(Bg), 201 (Bg), 210 (Ag), 227 (Ag), 250 (Ag), 264(Ag), 264 (Ag), 280 (Bg), 302 (Bg), 321 (Bg), and 338 cm-1 (Ag). Hydroxyl stretching modes are observed at 3050, 3218, 3333, 3449 and 3479 cm-1, in the infrared spectrum. Raman active hydroxyl bands are detected at 3009 (Bg), 3052 (Ag), 3190 (Bg) 3203 (Bg), 3281 (Ag) and 3310 (Bg), 3436 (Bg) and 3443 (Ag) cm-1. Infrared hydroxyl bands at 3050, and 3218 cm-1 are from water type II, short hydrogen bonding distances, and the bands at 3449 and 3479 cm-1 are due to water I, long hydrogen bonding distances. Water bending modes are detected in the infrared spectrum at 1571, 1621, 1641, and 1682 cm-1, but due to the inherent weak Raman scattering cross section of water these could not be detected in the Raman spectra
Raman spectroscopic detection of wyartite in the presence of rabejacite

Raman microscopy has been used to affirm the presence of wyartite\ud
CaU5+(UO2)2(CO3)O4(OH)(H2O)7 in the presence of rabejacite\ud
(Ca(UO2)4(SO4)2(OH)5.6H2O) obtained from the Ranger Mine, Northern Territory,\ud
Australia. This occurrence is somewhat unusual in that it means that a uranyl\ud
carbonate has been formed under acid conditions. Wyartite is a mineral known for the\ud
occurrence of pentavalent U5+. 1 A band is observed at 818 cm-1 in the Raman\ud
spectrum of wyartite assigned to the ν2 symmetric bending mode of the (CO3)2- units.\ud
The presence of carbonate is confirmed by the ν1 stretching vibration at 1071 cm-1 and\ud
the ν3 stretching vibrations at 1445 and 1345 cm-1. Two bands are observed at 853\ud
and 837 cm-1 and are assigned to the ν1 stretching modes of the UO2 units. Raman\ud
spectroscopy enables the partial band separation of the ν2 (CO3)2- and ν1 modes of\ud
UO2. The Raman spectrum of rabejacite is characterised by an intense sharp band at\ud
1010 cm-1 assigned to the ν1 stretching mode of (SO4)2- . Three bands observed at\ud
1086, 1123 and 1175 cm-1 are attributed to the ν3 antisymmetric stretching modes of\ud
(SO4)2-. The mineral rabejacite is also characterised by ν2 bending modes at 457 and\ud
394 cm-1 and ν4 bending modes at 666, 605, 537 and 505 cm-1. Raman spectroscopy\ud
has proven most useful for the detection of wyartite in the presence of other mineral\ud
phases
Hot-stage Raman spectroscopic study of the thermal decomposition of saleeite

Hot stage Raman spectroscopy has been used to study the changes in structure of saléeite (Mg(UO2)2(PO4)2.10H2O) during dehydration. Raman spectra were obtained using a Renishaw Raman microscope coupled with a Linkham thermal stage. Temperatures for Raman spectroscopic analysis were selected by studying the high resolution thermogravimetric analysis of the mineral saléeite. Five stages of dehydration are observed at 43, 73, 87, 231 and 376 degrees Celsius with the loss of 3, 3, 2, 1 and 1 mole of water respectively.  Three antisymmetric PO4 stretching vibrations are observed at 1007, 994 and 980 cm-1. No symmetric stretching vibration is observed until after significant dehydration has occurred at 75 degrees Celsius, when a low intensity band at 927 cm-1 is observed. Two bands at 843 and 827 cm-1 are attributed to the symmetric stretching modes of the two UO2 vibrational modes resulting from the two non-equivalent UO bonds.  The low intensity band at 894 cm-1 is assigned to the UO2 antisymmetric stretching mode. The complexity that is observed in the ν3 antisymmetric stretching region of the PO4 units is also observed in the PO4 ν2 bending region.  Four bands are observed at 471, 446, 405 and 376 cm-1.  Two bands observed at 283 and 234 cm-1 are assigned to the (UO2)2+ bending modes. After dehydration it is suggested that the structure loses its distortion, takes on a tetragonal structure and hence the Raman spectra become less complex upon thermal treatment
Raman spectroscopic study of organo-montmorillonites

A Raman spectroscopic study on the organo-montmorillonites prepared at different concentrations has provided a detailed observation about the ordering conformation of HDTMA+ ions confined within the montmorillonite interlayer. The ordering conformation shows strong dependence on the concentration of the confined amine. Both wavenumber and band width of antisymmetric and symmetric stretching modes are sensitive to the ordering conformation of the inserted organic cation. Furthermore, the wavenumber of the antisymmetric stretching mode is more sensitive to the mobility of the tail of amine chain than that of symmetric stretching mode does. \ud
At room temperature, the conformational ordering is more easily to be effected by the packing density in the lateral model than in the paraffin-type model. However, at liquid nitrogen temperature, both the positions of antisymmetric and symmetric stretching modes are independent of the amine concentration, and the band width of symmetric stretching mode is sensitive to the ordering conformation of organic. Upon heating the organo-montmorillonites, both the position of the antisymmetric and symmetric stretching bands shift to higher wavenumbers, indicating the decrease of conformational ordering
Vibrational spectroscopic characteristics of phthalocyanine and naphthalocyanine in sandwich-type phthalocyaninato and porphyrinato rare earth complexes Part 11.  Raman spectroscopic characteristics of phthalocyanine in mixed [tetrakis(4-chlorophenyl) orphyrinato](phthalocyaninato) rare earth double-deckers

Raman spectroscopic data in the range of 500-1800 cm-1 for a series of 15 mixed \[tetrakis(4-chlorophenyl)porphyrinato](phthalocyaninato) double-decker complexes with tervalent rare earths MIII(TClPP)(Pc) (M = Y, La...Lu except Ce and Pm) and intermediate-valent cerium Ce(TClPP)(Pc) have been collected using laser excitation sources emitting at 632.8 and 785 nm. Comparison with the Raman spectra of corresponding bis phthalocyaninato) rare earths reveals that the Raman characteristics of mixed ring double-deckers are dominated by the phthalocyaninato-metal fragment M(Pc) and phthalocyanine exists as monoradical anion Pc•- in MIII(TClPP)(Pc) and dianion Pc2- in Ce(TClPP)(Pc), respectively. Under excitation at 632.8 nm that is in close resonance with the main Q absorption band of phthalocyanine ligand, typical Raman marker band of the monoanion radical Pc•- was observed at 1512-1519 cm-1 as a weak band resulting from the coupling of pyrrole C=C and aza C=N stretchings.  For Ce(TClPP)(Pc), a strong band at 1492 cm-1 with contributions from both pyrrole C=C and aza C=N stretchings as well as the isoindole stretching was the marker Raman band of Pc2-. When excited with laser radiation of 785 nm, which is far away from the main Q absorption band of the phthalocyanine ligand, the marker Raman band of Pc•- in MIII(TClPP)(Pc) is observed at 1495-1514 cm-1 and of Pc2- in Ce(TClPP)(Pc) at 1511 cm-1 as a strong band
Effect of the lanthanide ionic radius on the raman spectroscopy of lanthanide agardite minerals

Raman microscopy has been used to study the Raman spectra of a series of rare earth\ud
element agardites ACu6(AsO4)3(OH)6.3H2O where A = lanthanide3+. These minerals\ud
have a porous framework similar to that of zeolites with a structure based upon\ud
(A3+ )1-x(A2+)xCu6(OH)6(AsO4)3-x(AsO3OH)x . Two sets of AsO stretching vibrations\ud
were found and assigned to the vibrational modes of AsO4 and HAsO4 units. The\ud
position of selected bands was found to be sensitive to the lanthanide ionic radius.\ud
Raman spectra of the low wavenumber region are complex. Bending modes of the\ud
AsO4 and HAsO4 units were found to be sensitive to the ionic radius of the lanthanide\ud
ion. Linear relationships between positions of the Raman bands were derived, with\ud
correlation coefficients > 0.90
FT-Raman and FT-IR spectroscopic study of the local structure of synthetic Mg/Zn/Al-hydrotalcites

Synthetic <i>Mg/Zn/Al</i>-hydrotalcites with atomic ratios of 6:0:2, 4:2:2, 2:4:2 and 0:6:2 were characterized by FT-Raman and FT-IR spectroscopy. ‘Al--OH’ IR translation modes are observed at 419, 427, 559, 616 and 771 cm<sup>−1</sup> with two corresponding Raman bands at 465–477 and 547–553 cm<sup>−1</sup>. ‘Mg--OH’ IR translation modes are found at 412, 559 and 616 cm<sup>−1</sup> with equivalent Raman bands at 464–477 and 547–553 cm<sup>−1</sup>. The ‘Zn--OH’ IR translation mode is found at 445 cm<sup>−1</sup> and the Raman modes around 450 and 495 cm<sup>−1</sup>. The CO<sub>3</sub><sup>2 −</sup> group is identified by the ν<sub>1</sub>(IR) at 1112 cm<sup>−1</sup> and a doublet in the Raman around 1045–1055 and 1060 cm<sup>−1</sup>. ν<sub>2</sub>(IR) is observed at 874 cm<sup>−1</sup>. ν<sub>3</sub>(IR) is a doublet at 1359 and 1381 cm<sup>−1</sup>. ν<sub>4</sub> is observed in both the IR and Raman spectra around 670 and 695–715 cm<sup>−1</sup>, respectively. In the OH deformation region, a doublet is observed for ‘Al--OH’ at 955 and 1033 cm<sup>−1</sup> in the IR spectra. The ‘Zn--OH’ IR deformation mode is observed at 1462 cm<sup>−1</sup>. H<sub>2</sub>O is characterized by a bending mode at 1632 cm<sup>−1</sup> and an H-bonded interlayer H<sub>2</sub>O mode at 3266 cm<sup>−1</sup> with a Raman band between 3244 and 3271 cm<sup>−1</sup>. The OH stretching region is characterized by three bands in the Raman spectra around 3355–3360, 3440–3455 and 3535–3580 cm<sup>−1</sup>. One band is observed in the IR spectra at 3471 cm<sup>−1</sup>
Raman spectroscopy of gerhardtite at 298 and 77 K

Raman spectroscopy has been used to study the nature of gerhardtite, a\ud
naturally occurring basic copper(II) nitrate of formula Cu2NO3(OH)3. Raman spectra\ud
at 77 K show four bands at 3557, 3548, 3467 and 3409 cm-1 in accordance with the\ud
crystal structure with three non-equivalent hydroxyl groups. Estimations of hydrogen\ud
bond distances of 0.3019, 0.2987, 0.2855 and 0.2804 pm are obtained. Cooling to\ud
liquid nitrogen temperatures did not affect these values. Two bands are observed at\ud
1048 and 1052 cm-1 in the NO3 stretching region. Cooling to liquid nitrogen\ud
temperature altered the ratio of these nitrates from 3/1 to 1/3. Two sets of bands in\ud
the antisymmetric stretching region of the nitrate in the 77 K spectra suggest that there\ud
are two non-equivalent nitrate anions in the gerhardtite structure at liquid nitrogen\ud
temperature. X-ray crystallography suggests three independent oxygens in the one\ud
nitrate group. The shift in band positions on obtaining Raman spectra at 298 and 77 K\ud
indicates a phase change is occurring for the mineral upon cooling to 77 K