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1.
The role of the late Cimmerian unconformity for the distribution of kaolinite in the Gullfaks Field, northern North Sea 总被引：2，自引：0，他引：2
A study of the Middle Jurassic Rannoch Formation in the Gullfaks Field shows that there is no relationship between the content and distribution of kaolinite and location relative to the late Cimmerian unconformity. From petrographic data most of the kaolinite is interpreted to be detrital, and only traces of authigenic kaolinite are observed. Mass-balance calculations are used to provide guidelines as to the likelihood of kaolinite being formed and preserved in sandstones under the unconformity. The result of the calculations shows that the propagation rate of the dissolution front in the sandstones was probably on average slower than the erosion rates during the formation of the late Cimmerian unconformity. Hence, transformation of significant amounts of feldspar and mica to kaolinite probably did not take place within the sandstones which at present underlie the unconformity in the Gullfaks Field. Periods of exposure during formation of unconformities may thus be less effective causes of kaolinitization in sandstones than has been assumed. 相似文献
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3.
OLAV LIESTøL 《Polar research》1986,4(1):97-101
In mainland Norway, mass balance measurements were carried out on the Hardangerjøkulen and Storbreen glaciers. Both had a small negative net balance. The two glaciers measured in Svalbard, Broggerbreen and Lovgnbreen, also had negative balances as in the previous 19 years. Length fluctuations measured at eight glacier tongues indicate that one was advancing, one in equilibrium, and six were retreating. 相似文献
4.
Jan Mayen is a small (373 km2 ) remote island in the Norwegian Sea. One third of it is covered by glaciers, all located on the Beerenberg volcano. There have been at least two Holocene periods of glacier expansion at Jan Mayen. The first may have taken place around 2500 B.P. Some glaciers had their maximum extent during the second period, around 1850 A.D. They have subsequently shown an oscillating retreat, with marked expansion around 1910, and with a minimum extent around 1950. Many glaciers advanced again around 1960. The advance of Sørbreen probably culminated around 1965. The climate appears to have been more arctic-continental than today during these two periods of glacier advances, caused by expanded pack ice cover in the East Greenland current and strong influence from the Greenland-Arctic high pressure area. The interplay between the high pressure area and the low pressure tracks in the North Atlantic Ocean determines the climate over the north-western part of the Atlantic, and this results in parallel climate and glacier variations within this region. We conclude, contrary to previous reports, that the advances of the glaciers around 1960 were caused by reduced summer temperatures and ablation, and not by increased precipitation. 相似文献
5.
Expanding spread profile at the northern Jan Mayen Ridge 总被引：1，自引：0，他引：1
An expanding spread seismic profile at the central northern Jan Mayen Ridge, ESP-5, has yielded a crustal seismic velocity distribution which is similar to observations from the thinned continental crust at the Norwegian continental margin. The profile reveals a post-early Eocene sedimentary sequence, about 1. 5 km thick, overlying 1 km of volcanic extrusives and interbedded sediments. Below, there are about 3 km of pre-opening sediments above the seismic basement. The results indicate that the main ridge block is underlain by a thinned crust, possibly only 13.5 km thick. The results are compatible with a continental nature for the main ridge complex. 相似文献
6.
YI-ZENG LIANG OLAV M. KVALHEIM Department of Chemistry University of Bergen N- Bergen NorwayAGNAR HOSKULDSSON Danish Engineering Academy DK- Lyngby Denmark 《地理学报(英文版)》1993,(4)
In this paper we redefine the term detection limit to embrace the inherent multivariate nature of samples,instrumental measurements and chemometrics resolution procedures. The so-called zero-componentregions, i.e. parts with no chemical components eluting, are used as repeated analytical blanks to estimatea statistical multivariate detection limit for determining the number of chemical species in local regionsof a single two-way chromatogram or a collection of synchronized one-way chromatograms. For two-waychromatography the detection limit is determined from the distribution of the first eigenvalues obtainedfrom all possible combinations of spectra in the zero-component regions. The number of spectra in eachcalculation should correspond to the number included in the later examination of the local retention timeregions. For one-way chromatography on a collection of samples with similar chemical components atvarying concentrations the same procedure is used, with the samples taking the role of the spectra intwo-way chromatography. The detection limit can be chosen at various confidence levels depending onwhether false positive or negative detection of minor components is most critical. The results obtainedfrom the zero-eigenvalue distribution are more robust than those obtained by a previously developedF-test. 相似文献
7.
DORI J. KOVANEN OLAV SLAYMAKER 《Boreas: An International Journal of Quaternary Research》2005,34(2):157-175
Kovanen, D. J. & Slaymaker, O. 2005 (May): Fluctuations of the Deming Glacier and theoretical equilibrium line altitudes during the Late Pleistocene and Early Holocene on Mount Baker, Washington, USA. Boreas , Vol. 34, pp. 157–175. Oslo. ISSN 0300–9483.
The Deming Glacier is presently nourished by an ice-cap type accumulation area on Mount Baker (3285 m a.s.l.). The specific meso-scale (>10km) form and isolation of the Mount Baker stratovolcano seem to influence temperature and precipitation gradients (contemporary climate data). These data are used as a reference when calculating paleo-equilibrium-line altitudes (ELAs). Six radiocarbon dates are reported, between 10 680 70 and 10 500 7014 C yr BP (12 903–12 183 cal. yr BP) from detrital logs in drift that were buried during an advance of the Deming Glacier (altitude 3230–1158 m) during possibly the Younger Dryas interval. The calculated range of theoretical ELA depressions (ΔELA) relative to modern is 400–355 m using two different methods. Assuming no change in precipitation, ablation-season temperature would have been 2.5–2.2C cooler, which is consistent with other paleoclimatic reconstructions in this region. Alternatively, assuming that the modern reference climate is appropriate, and based on regressions of modern-day glacial conditions, the predicted mean winter precipitation necessary to support the former Deming Glacier was in the order of 200–150% (mean 175%) or 119–86% (mean 103%). This amount of precipitation could result from reinvigorated moisture transport into the North Cascades and increased seasonality at the end of the last glaciation. 相似文献
The Deming Glacier is presently nourished by an ice-cap type accumulation area on Mount Baker (3285 m a.s.l.). The specific meso-scale (>10km) form and isolation of the Mount Baker stratovolcano seem to influence temperature and precipitation gradients (contemporary climate data). These data are used as a reference when calculating paleo-equilibrium-line altitudes (ELAs). Six radiocarbon dates are reported, between 10 680 70 and 10 500 70
8.
As in previous years Norsk Polarinstitutt has carried out mass balance investigations on Storbreen and Hardangerjøkulen in mainland Norway and on Broggerbreen and Lovenbreen in Svalbard. More than 20 years of measurements show that the glaciers both in mainland Norway and in Svalbard are retreating.
Both in 1985 and in 1986 the glaciers in Norway had a negative net balance. At Storbreen the mean annual net balance value 1949-86 is -0.30 m in water equivalents, while on Hardangerjflkulen the mean value 1963-86 is -0.02 m.
The two glaciers measured in Svalbard also had negative net balance in 1985 and in 1986. Both measured glaciers have had negative balance nearly all years since the measurements started in 1966. The mean value is close to -40g/cm2 or -0.4 m on both. 相似文献
Both in 1985 and in 1986 the glaciers in Norway had a negative net balance. At Storbreen the mean annual net balance value 1949-86 is -0.30 m in water equivalents, while on Hardangerjflkulen the mean value 1963-86 is -0.02 m.
The two glaciers measured in Svalbard also had negative net balance in 1985 and in 1986. Both measured glaciers have had negative balance nearly all years since the measurements started in 1966. The mean value is close to -40g/cm
9.
OLAV SLAYMAKER 《水文科学杂志》2013,58(6):567-573
Abstract The term debris torrent was introduced in North America's Pacific Northwest region to describe coarse-grained, rapid channelized flows rich in organic debris. Environmental conditions favouring their occurrence and distinctive criteria for recognition of debris torrents are discussed. A classification of gravitational and fluvial sediment transporting processes is presented as a framework for papers presented at the Debris Torrent Workshop 6a held in Vancouver in August, 1987. 相似文献
10.
STEPHEN R. HICOCK OLAV B. LIAN 《Boreas: An International Journal of Quaternary Research》1999,28(4):531-542
Glaciotectonic structures in subglacial till and substrate, as well as stone fabric, provenance and surface features in till, indicate that complex interactions of late Wisconsinan glacial lobes occurred along a mountain front in the western Fraser Lowland of southwestern British Columbia. Tills of this study represent subglacial deposition through the maxima of two stades in the Fraser Glaciation, the Coquitlam and the Vashon. Through each stadial maximum, temperate glacial ice was grounded and commonly overrode proglacial outwash while superimposing deformations in subglacial till during three phases: (1) pre-maximum glacier flow down valleys and into lowland piedmont ice, (2) coalescent piedmont ice during stadial maxima when flow was westward along the mountain front and across valley mouths, and (3) post-maximum glacier flow down valleys into lowland piedmont ice but prior to general deglaciation. Valley glaciers appear to have shifted flow directions during phases 1 and 3. During stadial maxima (phase 2), Fraser Lowland piedmont ice may have been part of an outlet glacier-ice stream complex that terminated in salt water over the continental shelf. 相似文献