Six-year record of atmospheric carbon dioxide and methane at a high-altitude mountain site in Poland   总被引：2，自引：0，他引：2  

JAROSLAW NECKI  MARTINA SCHMIDT  KAZIMIERZ ROZANSKI  MIROSLAW ZIMNOCH  ADAM KORUS  JAN LASA  ROLF GRAUL  INGEBORG LEVIN 《Tellus. Series B, Chemical and physical meteorology》2003,55(2):94-104

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Petrological, Geochemical and Isotopic Constraints on the Origin of the Harzburg Intrusion, Germany   总被引：1，自引：0，他引：1  

SANO  SAKAE; OBERHANSLI  ROLAND; ROMER  ROLF L.; VINX  ROLAND 《Journal of Petrology》2002,43(8):1529-1549

We present mineralogical, petrological and geochemical datato constrain the origin of the Harzburg mafic–ultramaficintrusion. The intrusion is composed mainly of mafic rocks rangingfrom gabbronorite to quartz diorite. Ultramafic rocks are veryrare in surface outcrops. Dunite is observed only in deepersections of the Flora I drill core. Microgranitic (fine-grainedquartz-feldspathic) veins found in the mafic and ultramaficrocks result from contamination of the ultramafic magmas bycrustal melts. In ultramafic and mafic compositions cumulatetextures are widespread and filter pressing phenomena are obvious.The order of crystallization is olivine pargasite, phlogopite,spinel plagioclase, orthopyroxene plagioclase, clinopyroxene.Hydrous minerals such as phlogopite and pargasite are essentialconstituents of the ultramafic cumulates. The most primitiveolivine composition is Fo_89·5 with 0·4 wt % NiO,which indicates that the olivine may have been in equilibriumwith primitive mantle melts. Coexisting melt compositions estimatedfrom this olivine have mg-number = 71. The chemical varietyof the rocks constituting the intrusion and the mg-number ofthe most primitive melt allow an estimation of the approximatecomposition of the mantle-derived primary magma. The geochemicalcharacteristics of the estimated magma are similar to thoseof an island-arc tholeiite, characterized by low TiO₂ and alkalisand high Al₂O₃. Geochemical and Pb, Sr and Nd isotope data demonstratethat even the most primitive rocks have assimilated crustalmaterial. The decoupling of Sr from Nd in some samples demonstratesthe influence of a fluid that transported radiogenic Sr. Leadof crustal origin from two isotopically distinct reservoirsdominates the Pb of all samples. The ultramafic rocks and thecumulates best reflect the initial isotopic and geochemicalsignature of the parent magma. Magma that crystallized in theupper part of the chamber was more strongly affected by assimilatedmaterial. Petrographic, geochemical and isotope evidence demonstratesthat during a late stage of crystallization, hybrid rocks formedthrough the mechanical mixing of early cumulates and melts withstrong crustal contamination from the upper levels of the magmachamber. KEY WORDS: Harzburg mafic–ultramafic intrusion; Sr–Nd–Pb isotopes; magma evolution; crustal contamination  相似文献   

Palaeomagnetic chronostratigraphy of Holocene sediments,Niagara basin,Lake Ontario,Canada     

ROLF GEORGE PIPPERT  G. R. BROWN  W. A. MORRIS 《第四纪科学杂志》1996,11(3):217-231

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Patterns of production and sedimentation in the boreal and polar Northeast Atlantic   总被引：7，自引：0，他引：7  

PAUL WASSMANN  ROLF PEINERT  VICTOR SMETACEK 《Polar research》1991,10(1):209-228

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Estimation of observation impact using the NRL atmospheric variational data assimilation adjoint system   总被引：2，自引：0，他引：2  

ROLF H. LANGLAND  NANCY L. BAKER 《地球，A辑:动力气象学与海洋学》2004,56(3):189-201

An adjoint-based procedure for assessing the impact of observations on the short-range forecast error in numerical weather prediction is described. The method is computationally inexpensive and allows observation impact to be partitioned for any set or subset of observations, by instrument type, observed variable, geographic region, vertical level or other category. The cost function is the difference between measures of 24-h and 30-h global forecast error in the Navy Operational Global Atmospheric Prediction System (NOGAPS) during June and December 2002. Observations are assimilated at 00 utc in the Naval Research Laboratory (NRL) Atmospheric Variational Data Assimilation System (NAVDAS). The largest error reductions in the Northern Hemisphere are produced by rawinsondes, satellite wind data, and aircraft observations. In the Southern Hemisphere, the largest error reductions are produced by Advanced TIROS Operational Vertical Sounder (ATOVS) temperature retrievals, satellite wind data and rawinsondes. Approximately 60% (40%) of global observation impact is attributed to observations below (above) 500 hPa. A significant correlation is found between observation impact and cloud cover at the observation location. Currently, without consideration of moisture observations and moist processes in the forecast model adjoint, the observation impact procedure accounts for about 75% of the actual reduction in 24-h forecast error.  相似文献   

Modelling the chemistry of ozone, halogen compounds, and hydrocarbons in the arctic troposphere during spring     

ROLF SANDER  RAINER VOGT  GEOFF W. HARRIS  PAUL J. CRUTZEN 《Tellus. Series B, Chemical and physical meteorology》1997,49(5):522-532

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A Tertiary-Quaternary section at Sarsbukta, Spitsbergen, Svalbard, and its foraminifera     

ROLF W. FEYLING-HANSSEN  KAARE ULLEBERG 《Polar research》1984,2(1):77-106

Tertiary and Quaternary deposits outcrop in the coastal cliff of Balanusviken at Sarsbukta in Vest-Spitsbergen. The Tertiary deposits appear by their foraminifera to belong to the Middle to Upper Oligocene. The Quaternary deposits consist of an upper part of Late Pleistocene to Holocene age, and a lower part which had previously been considered Middle Weichselian of age. Its foraminiferal assemblages suggest a higher age (Late Saalian, Eemian?). This lower part of the Quaternary deposits is related to a series of raised beaches with an upper limit at SO m above present day sea level. They were probably formed during the Eemian, and have not been distorted by later glaciation. The present study is based on sediment samples collected from the coastal cliff of Balanusviken, and particularly from that of Balanuspynten, Sarsbukta, Spitsbergen, during the summer expedition of Norsk Polarinstitutt in 19Sø.  相似文献   

Cave stratigraphy in western Norway; multiple Weichselian glaciations and interstadial vertebrate fauna     

EILIV LARSEN  STEINAR GULLIKSEN  STEIN-ERIK LAURITZEN  ROLF LIE  REIDAR LØVLIE  JAN MANGERUD 《Boreas: An International Journal of Quaternary Research》1987,16(3):267-292

Skjonghclleren is a marine-cut cave with 15–20. m thick pre-Holocene sediments. Corings and excavations reveal three beds of extremely fine-grained, laminated sediments alternating with blocky sediments. The laminated beds are interpreted as glaciolacustrine sediments deposited subglacially at times when ice sheets covered the area, suggesting at least three glaciations after the cave was formed. The blocky/diamictic sediments were formed by frost-shattered blocks from the roof of the cave during ice-free periods, and mixing with the fines through slow mass movements along the floor of the cave. In the diamictic sediment beneath the uppermost laminated bed, almost 7,000 bone and teeth fragments of birds, mammals and fish were found. Birds dominated, with little auk and brunnich's guillemot as the most frequently occurring species. Arctic fox was the dominating mammal. During climatic optimum of the interstadial, conditions seem to have been similar to present-day coastal Finnmark, with North Atlantic warm water entering the Norwegian Sea. Two radiocarbon dates on bones and three Uranium series dates on speleothems from this bed all cluster around 30,000 B.P., i.e., the end of the Ålesund interstadial. Above the uppermost laminated bed, bone fragments of birds, fish and mammals, deposited between c . 12,000 and c . 10,000 B.P., were found. Little auk dominate. The occurrence of squirrel is worth noting since it is limited mainly to areas with coniferous forest today. The beds below the 30,000B.P. bed are poorly dated or undated, but it is tentatively concluded that the entire sediment sequence was deposited during the Weichselian stage. It seems that the cave was formed at a high relative sea-level stand sometime during the Early Weichsclian. Two recorded palaeomagnetic excursions seem to correlate with the Laschamp/Olby and the Lake Mungo events, respectively.  相似文献