bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coal geology, chemical and petrographical characteristics, and implications for coalbed methane development of subbituminous coals from the Sorgun and Suluova Eocene basins, Turkey
Authors: Karayigit A. I. , Eris E. , Cicioglu E. 
Published: September 2007

Abstract
The Sorgun and Suluova basins contain a thick and laterally extensive Lower Eocene coal seam. The stratigraphy of both basins comprises basement rocks, the Yozgat Granitoid of Pre-Eocene age in the Sorgun basin and Jurassic-Cretaceous limestones in the Suluova basin, overlain unconformably by the coal-bearing Lower Eocene Celtek Formation and by transgressive units of Middle-Upper Eocene age. In the Sorgun basin the Artova Ophiolitic Complex tectonically overlies the transgressive units. Neogene and Quaternary deposits cover all the older units unconformably in both basins. The single coal seam is located at the base of the Celtek Formation and reaches a thickness of 6 m in the open-cast mine at Sorgun and 8 m in boreholes in the Suluova basin. Some coal is produced by opencast mining, but most is produced by underground mining methods.
A total of 75 coal samples was collected from both basins and analysed chemically and petrographically. The coals are characterized by a relatively low moisture content (0.7–9.3 wt% on an air-dried basis) and variable ash yields (2.4–67.8 wt% on an air-dried basis) and huminite contents (28.4–89.6 vol%). Measurements of the mean random reflectance of ulminite (mainly eu-ulminite A) vary between 0.46 and 0.60% (0.53% average). These reflectance values and the chemical analyses show that the rank is subbituminous A or transitional to high-volatile bituminous C coal according to the ASTM classification.
The coalbed methane potential of both basins is at present unknown. No borehole has been drilled to explore for this resource and no gas capacity value has been obtained for the coal seam and bituminous shales. The methane explosions which have occurred during coal production in the underground mines imply that both basins may have been an important potential for coalbed methane.
Abrupt changes in marine conditions, Sunneshine Fiord, eastern Baffin Island, NWT during the last deglacial transition: Younger Dryas and H-0 events
Authors: Andrews J. T. , Osterman L. E. , Jennings A. E. , Syvitski J. P. M. , Miller G. H. , Weiner N. 
Published: September 2007

Abstract

Sunneshine Fiord is a shallow fiord that lies at the easternmost tip of Baffin Island, NWT,
c
. 66°33′ N on the western end of Davis Strait, a 600 m deep sill that links Baffin Bay to the north with the Labrador Sea and the North Atlantic in the south. Offshore surface circulation today consists principally of the southward transport of Polar Water in the Baffinland Current. Raised marine deposits in the outer part of the fiord are radiocarbon dated at >57 ka and can be associated with large lateral moraines on both walls of the fiord; Holocene raised marine sediments appear to be absent. A gravity and piston core together (HU82-031-SU5) sample about 8.5 m of the sediment fill. Nine AMS
14
C dates on marine shells and foraminifera indicate that the coring recovered sediments that span around 14 calibrated (cal) of record. Seismic surveys indicate that the upper sediment is acoustically transparent and overlies acoustically stratified materials. There is a major reflector towards the base of the cored section. Analyses of physical properties, lithofacies and biofacies indicate that there is a very sharp break in the record at around 12.4 cal ka, which is interpreted as a change from relatively ice-distal conditions to one characterized by a dramatic increase in cold, ice-proximal foraminiferal benthic species, notably
Elphidium excavata
forma
clavata
. At the same time, there was an extremely abrupt increase in detrital carbonate, most of which is dolomite. Because there is no known local source of detrital carbonate within the fiord, this abrupt event signals an increase in the transport of detrital carbonate derived from icebergs and/or meltwater from sources further north in Baffin Bay, or immediately to the south from Cumberland Sound. The onset of this event at 12. 4 cal ka is synchronous with evidence for an abrupt increase in detrital calcitic carbonate emanating from an ice re-advance within and probably across Hudson Strait. These events are the probable source of detrital calcitic carbonate in the northwestern North Atlantic associated with the Younger Dryas cold period and iceberg rafting event, H-0.
Shelf erosion and glacial ice proximity in the Labrador Sea during and after Heinrich events (H-3 or 4 to H-0) as shown by foraminifera
Authors: Jennings Anne E. , Tedesco Kathy A. , Andrews John T. , Kirby Matthew E. 
Published: September 2007

Abstract

Collapses of the marine-based Laurentide Ice Sheet during the last glaciation are documented by large, abrupt influxes of detrital carbonate into the northwest Labrador Sea, known as detrital carbonate or Heinrich events. The extent of grounded ice on the continental shelf is poorly constrained for these events, but has been assumed to be at the shelf edge. Possible grounding line positions of ice streams in Hudson Strait and Cumberland Sound over the last
c.
34 ka are delimited using the abundance of shelf-dwelling benthic foraminifera, sediment colour and calcite to dolomite ratios in two Labrador Sea cores (87033-009 LCF and 75-009-IV-55 PC). Heinrich events 1 and 2 contain no evidence of glacial erosion of the continental shelf, suggesting that the Hudson Strait ice stream may have grounded on the Hudson Strait sill or on the inner shelf rather than at the shelf edge during these events. Dark grey, dolomite-rich sediments with abundant shelf-dwelling foraminifera document an advance of Cumberland Sound ice onto the shelf after H-3 or H-4 (
c.
34 ka), but before H-2 (
c.
21 ka). Cumberland Sound ice readvanced to a position at or near the shelf edge at
c.
11.1 ka, during the Younger Dryas chron. This advance is nearly synchronous with an advance of Labradorean ice on the southeastern Baffin Shelf and with a detrital carbonate event in Sunneshine Fjord, to the north, suggesting climatic forcing of separate ice dispersal centres during the Younger Dryas.
Deglaciation of the inner Scotian Shelf, Nova Scotia: correlation of terrestrial and marine glacial events
Authors: Stea R. R. , Boyd R. , Costello O. , Fader G. B. J. , Scott D. B. 
Published: September 2007

AbstractThe inner continental shelf off Nova Scotia is an important region for correlating glacial events across the terrestrial-marine transition. The inner Scotian Shelf can be subdivided into five coast-parallel terrain zones which record glaciation and the rise and fall of relative sea levels during the late glacial period. During the initial deglaciation phase (c.17–15 ka) ice was drawn out of the Gulf of Maine, isolating an ice mass over Nova Scotia which later became an active centre of outflow (Scotian Ice Divide). The Scotian Shelf End-Moraine Complex (SSEMC) formed at the margin of this glacier. Landward of the end moraine complex is a series of linear depositional basins termed the Basin Zone, containing a complete sedimentary record of events after deposition of the SSEMC. The lowest depositional sequences (sequences 1 and 2) in these basins are interpreted to be ice-proximal sediment, deposited by overflow and interflow meltwater plumes emanating from the retreating ice margin. From 13–12 ka, the sea level dropped rapidly due to glacial isostatic recovery. Ice receded out of marine areas, depositing the glacial-marine sequence 3 in the Basin Zone. A lowstand shoreline (c.11.6 ka) at −65 m is marked by the landward transition from morainal topography to a shoreface ramp, terrace and wave-cut platform. Enhanced current erosion during the lowstand was recorded in the inner Scotian Shelf basins by erosional truncation of sequence 3. After this erosional event the sea level rose rapidly, concomitant with climatic warming, as indicated by foraminifera within the Basin Zone and increases in spruce pollen in cores from Nova Scotia lakes. In the Basin Zone a seismic sequence characterized by indistinct, low-amplitude reflections (sequence 4) was deposited. Increased storminess and current sediment delivery with increased sea ice and icebergs during the Younger Dryas climatic cooling (c.11–10.0 ka) produced sequence 5 in the Basin Zone. Sequence 5 is correlative with a distinctive mineralic layer in lakes and periglacial and glacial sediments that overlie peat in land sections. The terrestrial and marine sections record a transition from organic-rich to inorganic sedimentation events initiatedc.10.8 ka. Climatic cooling and snowfield/glacier build-up on land, with increased meltwater runoff and storm-induced sedimentation in the marine realm, were the principal causes of these sedimentation events.
Deep-sea ostracode shell chemistry (Mg:Ca ratios) and Late Quaternary Arctic Ocean history
Authors: Cronin Thomas M. , Dwyer Gary S. , Baker Paul A. , Rodriguez-Lazaro Julio , Briggs William M. 
Published: September 2007

Abstract

The magnesium:calcium (Mg:Ca) and strontium:calcium (Sr:Ca) ratios were investigated in shells of the benthic ostracode genus
Krithe
obtained from 64 core-tops from water depths of 73 to 4411 m in the Arctic Ocean and Nordic seas to determine the potential of ostracode shell chemistry for palaeoceanographic study. Shells from the Polar Surface Water (−1 to −1.5°C) had Mg:Ca molar ratios of about 0.006–0.008; shells from Arctic Intermediate Water (+0.3 to +2.0°C) ranged from 0.09 to 0.013. Shells from the abyssal plain and ridges of the Nansen, Amundsen and Makarov basins and the Norwegian and Greenland seas had a wide scatter of Mg:Ca ratios ranging from 0.007 to 0.012 that may signify post-mortem chemical alteration of the shells from Arctic deep-sea environments below about 1000 m water depth. There is a positive correlation (
r
2
= 0.59) between Mg:Ca ratios and bottom-water temperature in
Krithe
shells from Arctic and Nordic seas from water depths <900 m. Late Quaternary
Krithe
Mg:Ca ratios were analysed downcore using material from the Gakkel Ridge (water depths 3047 and 3899 m), the Lomonosov Ridge (water depth 1051 m) and the Amundsen Basin (water depth 4226 m) to test the core-top Mg:Ca temperature calibration. Cores from the Gakkel and Lomonosov ridges display a decrease in Mg:Ca ratios during the interval spanning the last glacial/deglacial transition and the Holocene, perhaps related to a decrease in bottom water temperatures or other changes in benthic environments.
North Atlantic sea surface conditions during the Younger Dryas cold event
Authors: Duplessy J. C. , Labeyrie L. D. , Paterne M. 
Published: September 2007

Abstract

A map has been drawn of the oxygen isotopic composition (
δ
18
O) of planktonic foraminifera which deposited their shells in isotopic equilibrium with ambient surface waters during the Younger Dryas cold event. These
δ
18
O values were derived from the
δ
18
O values of
Neogloboquadrina pachyderma
(left coiling) and
Globigerina bulloides
, which lived in their respective optimum temperature ranges. This map reflects the main trends of the sea surface temperature field during the Younger Dryas, but does not exhibit any
δ
18
O anomaly associated with continental ice-sheet melting. This result rules out all the theories relating the Younger Dryas cooling to injection of continental ice-sheet meltwater with very low
δ
18
O value into the North Atlantic Ocean. This reconstruction suggests that drifting of Arctic sea ice transported by the East Greenland Current may be a possible cause for the strong cooling which occurred in the middle of the last deglaciation.
Late glacial-Holocene sea surface temperatures and gradients between the North Atlantic and the Norwegian Sea: implications for the Nordic heat pump
Authors: Koç Nalân , Jansen Eystein , Hald Morten , Labeyrie Laurent 
Published: September 2007

Abstract
A S-N transect of sediment cores is used to (a) determine the millenial scale variability of sea surface temperatures (SSTs) and (b) the strength of the S-N SST gradients in the North Atlantic. The results show that the initial warming of the surface North Atlantic after the Last Glacial Maximum occurred synchronously between 50°N and 63°N at 13.4ka, but was delayed by 1000 years at 72°N. All cores indicate that the Bølling-Allerød period was a climatically unstable time interval punctuated by several SST coolings. However, the magnitudes of these brief coolings were strongly subdued in the North Atlantic compared with the eastern Norwegian Sea. Plotting SSTs on a S-N transect indicates the presence of a strong (9°C) gradient (the Arctic front) between the Norwegian Sea and the North Atlantic throughout the Bølling-Allerød period. This gradient became even stronger (15°C) during the Younger Dryas, and nearly disappeared during the Early Holocene. The observed SST gradients have implications for the magnitude of the oceanic heat pump and atmospheric circulation patterns of the late glacial period.
Late glacial sedimentology, foraminifera and stable isotope stratigraphy of the Hebridean Continental Shelf, northwest Scotland
Authors: Austin W. E. N. , Kroon D. 
Published: September 2007

Abstract

The detailed stratigraphies of two shallow marine cores from the Hebridean shelf of northwest Scotland are presented. The results provide evidence on the timing of deglaciation from about 15.2 ka
BP
, with evidence of cold, low salinity water persisting on the shelf until at least 13.5 ka
BP
. After 13.5 ka
BP
, probably shortly before 13.0 ka
BP
, warm shallow shelf seas were established and persisted throughout much of the interstadial. There is some evidence for climatic instability during the interstadial and for a cooling trend from after 11.6 ka
BP
. Glacial isostatic rebound of the shelf seems to have kept pace with eustatic sea level rise until about 11 ka
BP
.

The fully developed conditions of the Younger Dryas stadial are not observed until 11 ka
BP
. For the first time from the marine record the constituent tephra peaks of North Atlantic Ash Zone 1 are resolved into a sequence of eruptive events and demonstrate that extensive sea ice transgressed the western UK continental shelf throughout the Younger Dryas. The climatic conditions of the Younger Dryas persist until an initial, precursor warming at 10.2 ka
BP
, followed by a marked warming of about 8°C and fully established early Holocene temperatures before 10 ka
BP
. Many of the changes recorded through nearly 5 m of sediments accumulated during the Younger Dryas can be related to changing relative sea levels and source supply.
Marine mollescan proxy data applied to Scottish late glacial and Flandrian sites: strengths and limitations
Authors: Peacock J. D. 
Published: September 2007

Abstract
Knowledge of modern benthonic marine molluscs found in shallow water enables their distribution to be correlated with hydrographic conditions and the derived proxy data applied to late Quaternary assemblages. The application of such data for bottom temperature, minimum sea surface temperature and minimum salinity to four Flandrian and Late glacial sites shows that it is possible to follow changes in these parameters with time, in some cases in considerable detail. The chief limitations are that faunas from some boreholes and sections are sparse and of low diversity and that few taxa are restricted to narrow ranges of temperature and/or salinity. Where fossils of stenothermal and stenohaline species are absent from a profile, faunal analysis inevitably yields a less than precise picture of conditions. It is possible to give only generalized constraints on water depth because this is not a prime factor controlling the distribution of molluscs on the seafloor today. The palaeoenvironmental analysis of the four sites is briefly discussed in a wider context.
Late glacial sea level and ocean margin environmental changes interpreted from biostratigraphic and lithostratigraphic studies of isolation basins in northwest Scotland
Authors: Shennan Ian , Rutherford Mairéad M. , Innes James B. , Walker Kevin J. 
Published: September 2007

Abstract

Detailed biostratigraphic and lithostratigraphic analyses from isolation basins at Ardtoe, Rumach, Loch nan Eala and Fearnbeg, northwest Scotland, allow an interpretation of sea level movements and environmental changes within the Lateglacial Interstadial and Younger Dryas (13-10 ka
BP
). Microfossil analyses illustrate the gradual transition of the isolation basins from marine basins to freshwater lakes within an area of isostatic uplift. These data provide evidence for a fall in relative sea level in northwest Scotland from the mid-Lateglacial Interstadial to the early Holocene.

Pollen, diatom and dinoflagellate cyst (dinocyst) analyses link the oceanic record of major climate and oceanic circulation changes with the terrestrial biostratigraphic record. Movement of the oceanic Polar Front west and north during a period of relative climatic amelioration within the Lateglacial Interstadial and a corresponding change in the position of the North Atlantic Current may be inferred from the dinocyst record. This is followed by a relative cooling.
Late Weichselian environmental changes of the southern Kattegat, Scandinavia, inferred from diatom records
Authors: Jiang Hui , Nordberg Kjell 
Published: September 2007

Abstract

The diatom stratigraphy of a high-resolution sediment core, dated by the tandem accelerator mass spectrometry (AMS)
14
C method, records the environmental changes of the Late Weichselian in the southern Kattegat. Five diatom assemblage zones, with two subzones, are distinguished during the Allerød and Younger Dryas chronozones. Fresh water diatoms dominate the assemblages throughout the core. Salinities, particular the surface water salinity during the whole period, were much lower than that of today. Between 11 500 and 11 300 years bp, the occurrence of abundant freshwater planktonic species with only a few brackish water and marine species suggests an environment strongly affected by a great amount of meltwater discharged from the Baltic Ice Lake via the Öresund Strait. The period from the late Allerød to the early Younger Dryas between 11 300 and 10 600 years bp is characterized by an incursion of cold, saline water into the southern Kattegat with the strongest phase between 11 300 and 10 900 years bp, mirrored by increasing marine diatoms, especially sea ice species. Climatic amelioration took place at about 10 650 years bp, which occurred synchronously with a hydrographic change in the southern Kattegat. Relatively warm marine water, mixed with cold marine water, flowed into the Kattegat, although its impact on the southern Kattegat was small. Towards the end of this stage, the influence of saline water on the southern Kattegat became weaker, and a large amount of meltwater was discharged from the Baltic Ice Lake, which resulted in the surface water salinity decreasing greatly. An earlier change in the drainage pathway of the Baltic Ice Lake, from the Öresund Strait to south central Sweden, took place between 11 200 and 10 900 years bp. This was suggested by fewer planktonic freshwater diatoms and low sediment accumulation rates and/or a hiatus.
Palaeoceanography on the European arctic margin during the last deglaciation
Authors: Hald Morten , Dokken Trond , Hagen Sveinung 
Published: September 2007

Abstract

To reveal the palaeoceanographic and palaeoclimatic evolution related to the disintegration of the Barents Sea and Fennoscandian ice sheets, high-resolution sediment cores from the continental margin off western Svalbard, western Barents Sea and northern Norway were investigated. The location of these cores is below the axis of the Norwegian Current and beyond, but close to, glaciated continental areas. Hence they should sensitively reflect the palaeoceanography of the northernmost Norwegian Sea. Between, 14.5–19.5 and 22.5–29
14
C ka, a high abundance of planktonic foraminifera and a small content of subpolar species indicate seasonally ice-free and slightly warmed surface water. This phenomenon is related to the advection of surface water of North Atlantic origin. The onset of the deglaciation is characterized by a marked low oxygen event dated to between 15 and 13 ka, interpreted to reflect a surface water freshening produced by meltwater and reduced oceanic mixing. After the onset of deglaciation, the surface ocean warmed in three rapid steps: (1) around 12.5 ka, indicated by increased abundances of planktonic foraminifera; (2) at 10.2 ka and at (3) 10–9.6 ka. The two latter steps are reflected by the increased abundance of subpolar planktonic foraminifera.
Post-glacial environments of the southeastern Barents Sea: foraminiferal evidence
Authors: Polyak Leonid , Mikhailov Valery 
Published: September 2007

Abstract

Quaternary sediment records from the southeastern Barents Sea were used to reconstruct palaeoceanographic environments since the last deglaciation based on lithology, foraminiferal assemblages and AMS
14
C dates. After the ice sheet retreat at 13 ka
BP
two pulses of glacimarine sedimentation occurred, separated by non-deposition between approximately 12 and 10.5 ka
BP
. Proximal sedimentation from meltwater overflows prevailed during the first pulse, whereas the second pulse reflects distal glacimarine environments with some inflow of Atlantic water. Full marine environments were established by 9.3 ka
BP
, associated with increased Atlantic water advection, intensified currents and reduced sedimentation rates. The maximum Atlantic influence lasted until approximately 5 ka
BP
, followed by an advance of Arctic surface water with winter sea ice cover.
Palynology as a tool for land-sea correlation; an example from the eastern Mediterranean region
Authors: Zonneveld Karin A. F. , Boessenkool Karin P. 
Published: September 2007

Abstract

Sediments from two cores from the Adriatic Sea (Eastern Mediterranean), deposited between 18 and 9 ka
BP
, have been investigated with respect to their marine (dinoflagellate cyst) and terrestrial (pollen) fossil content. Based on contemporaneous changes in both the dinoflagellate cysts and pollen associations, a paleoclimatic reconstruction of the Adriatic Sea region is constructed for the studied time interval. Several intervals with increased Po River discharge are identified which may be subscribed to melting phases of the glaciers in the Alps and Apennines or increased winter precipitation in the region.
Earth rotation, ocean circulation and palaeoclimate: the North Atlantic — European example
Authors: Mörner Nils-Axel 
Published: September 2007

Abstract

The glacial eustatic rise in sea level after the 20 ka
BP
glaciation maximum led to an increase in the equatorial radius and hence a general deceleration in the Earth’s rate of rotation. The sea-level rise can be approximated by two superposed exponential curves with a transitional period about 13-10 ka radiocarbon years
BP
. This period is known to cause high-amplitude climatic changes and regionally irregular changes in sea level. This is interpreted as a break down in the Earth-Moon adjustment to the post-glacial deceleration, which was instead compensated by rapid re-distributions of oceanic water masses and interchanges of angular momentum between the hydrosphere and the solid Earth. At about 6000 years
BP
the glacial eustatic rise in sea level ended and a new set of circumstances began, which were characterized by feedback interchanges of angular momentum between the solid Earth and the hydrosphere. It is proposed that the palaeoclimatic changes on a decadal to millennial time-scale are primarily driven by the causal connection between the Earth’s rotation, oceanic circulation, ocean/atmosphere heating, atmospheric (wind) heat transport and continental palaeoclimatic changes.