The influence of climate,hydrology and permafrost on Holocene peat accumulation at 3500 m on the eastern Qinghai–Tibetan Plateau     

David J. Large  Baruch Spiro  Marion Ferrat  Michaela Shopland  Malin Kylander  Kerry Gallagher  Xiangdong Li  Chengde Shen  Goran Possnert  Gan Zhang  W. George Darling  Dominik Weiss 《Quaternary Science Reviews》2009,28(27-28):3303-3314

Peatland of the eastern Qinghai–Tibetan Plateau lies at the convergence of the East Asian and Indian monsoon systems in eastern Asia. To understand the evolution of this peatland and its potential to provide new insights into the Holocene evolution of the East Asian monsoon a 6 m peat core was collected from the undisturbed central part of a peat deposit near Hongyuan. The age-depth profile was determined using 16 ¹⁴C-AMS age dates, the peat analysed for a range of environmental variables including carbon, nitrogen and hydrogen concentration, bulk density, δ¹³C and the associated spring water analysed for hydrogen and oxygen isotopes. The age-depth profile of the recovered peat sequence covers the period from 9.6 to 0.3 kyr BP and is linear indicating that the conditions governing productivity and decay varied little over the Holocene. Using changes in carbon density, organic carbon content and its δ¹³C, cold dry periods of permafrost characterised by low density and impeded surface drainage were identified. The low δ¹⁸O and δD values of the spring water emanating around the peat deposit, down to ?13.8 and ?102‰ (VSMOW), respectively, with an inverse relationship between electrical conductivity and isotopic composition indicate precipitation under colder and drier conditions relative to the present day. In view of the current annual mean air temperature of 1 °C this suggests conditions in the past have been conducive to permafrost. Inferred periods of permafrost correspond to independently recognised cold periods in other Holocene records from across China at 8.6, 8.2–7.8, 5.6–4.2, 3.1 and 1.8–1.5 kyr BP. The transition to a cold dry climate appears to be more rapid than the subsequent recovery and cold dry periods at Hongyuan are of longer duration than equivalent cold dry periods over central and eastern China. Light–dark banding peat on a scale of 15–30 years from 9.6 to 5.5 kyr BP may indicate a strong influence of decadal oscillations possibly the Pacific Decadal Oscillation and a potential link between near simultaneous climatic changes in the northwest Pacific, ENSO, movement of the Intertropical Convergence Zone and the East Asian Monsoon.  相似文献   

Optical photometry using Bradford robotic telescope     

P. Seal Braun  J. E. F. Baruch 《Astrophysics and Space Science》2009,321(3-4):177-183

The Bradford Robotic Telescope (BRT) is located on Mount Teide at Tenerife and is working, taking observations since 2003. It is a fully automated telescope. The hardware and software used for the working of the telescope are described here. Twenty four BL Lac objects are observed since 2005 and magnitudes of the objects are calculated. We describe in this paper the working of BRT and optical BVR photometry of BL Lac objects, observed during 2005–2007.  相似文献   

Deducing the source and composition of rare earth mineralising fluids in carbonatites: insights from isotopic (C,O, <Superscript>87</Superscript>Sr/<Superscript>86</Superscript>Sr) data from Kangankunde,Malawi     

Sam?Broom-FendleyEmail authorView author&#;s OrcID profile  Frances?Wall  Baruch?Spiro  Clemens?V.?Ullmann 《Contributions to Mineralogy and Petrology》2017,172(11-12):96

Carbonatites host some of the largest and highest grade rare earth element (REE) deposits but the composition and source of their REE-mineralising fluids remains enigmatic. Using C, O and ⁸⁷Sr/⁸⁶Sr isotope data together with major and trace element compositions for the REE-rich Kangankunde carbonatite (Malawi), we show that the commonly observed, dark brown, Fe-rich carbonatite that hosts REE minerals in many carbonatites is decoupled from the REE mineral assemblage. REE-rich ferroan dolomite carbonatites, containing 8–15 wt% REE₂O₃, comprise assemblages of monazite-(Ce), strontianite and baryte forming hexagonal pseudomorphs after probable burbankite. The ⁸⁷Sr/⁸⁶Sr values (0.70302–0.70307) affirm a carbonatitic origin for these pseudomorph-forming fluids. Carbon and oxygen isotope ratios of strontianite, representing the REE mineral assemblage, indicate equilibrium between these assemblages and a carbonatite-derived, deuteric fluid between 250 and 400 °C (δ¹⁸O + 3 to + 5‰_VSMOW and δ¹³C ? 3.5 to ? 3.2‰_VPDB). In contrast, dolomite in the same samples has similar δ¹³C values but much higher δ¹⁸O, corresponding to increasing degrees of exchange with low-temperature fluids (< 125 °C), causing exsolution of Fe oxides resulting in the dark colour of these rocks. REE-rich quartz rocks, which occur outside of the intrusion, have similar δ¹⁸O and ⁸⁷Sr/⁸⁶Sr to those of the main complex, indicating both are carbonatite-derived and, locally, REE mineralisation can extend up to 1.5 km away from the intrusion. Early, REE-poor apatite-bearing dolomite carbonatite (beforsite: δ¹⁸O + 7.7 to + 10.3‰ and δ¹³C ?5.2 to ?6.0‰; ⁸⁷Sr/⁸⁶Sr 0.70296–0.70298) is not directly linked with the REE mineralisation.  相似文献   

Optical observations of transient luminous events associated with winter thunderstorms near the coast of Israel   总被引：1，自引：0，他引：1  

Yoav Yair  Colin Price  Michal Ganot  Eran Greenberg  Roy Yaniv  Baruch Ziv  Yosef Sherez  Adam Devir  Jo'zsef Br  Gabriella Stori 《Atmospheric Research》2009,91(2-4):529-537

We report the results of two observation campaigns conducted during the Northern Hemisphere winters of 2005–6 and 2006–7 aiming to detect transient luminous events (TLEs) above winter thunderstorms in the vicinity of Israel and the eastern coastline of the Mediterranean Sea. In 10 out of 31 different observation nights we detected 66 events: 56 sprites and 10 Elves. The detection ranges varied from 250 to 450 km. Sprites were found to be produced by active cells with a vertical dimension of 5–9 km and cloud top temperature ~ − 40 °C, embedded in a much larger matrix of stratiform precipitating cloudiness. This configuration closely resembles the conditions for winter sprites in the Hokuriku region of Japan. Synchronized with the optical observations, ELF data were recorded at two observation stations in Israel and Hungary in order to qualify and quantify parameters of the parent lightning discharge associated with the TLEs. These stations are located 500 km and 2100 km respectively from the Eastern Mediterranean Sea, where most TLEs occur. Among the optically observed TLE events, we found that all the ELF signals were produced solely by positive cloud-to-ground flashes (+ CGs), most of which were recorded in Israel (88%) and Hungary (77%). Calculation of the Charge Moment Change showed average values of 1400 ± 600 C km, with some extreme events exceeding 3500 C km. The average time delay between the ELF transient of the parent + CG and the observed sprites was 55 ms, with shorter delays for column sprites (42 ± 34 ms) compared to carrot sprites (68 ± 34). Furthermore, based on the ELF data, there were no early identifiable precursors to TLE occurrence in the regional lightning activity. From the spatial formation of the observed columniform sprites, we propose that columniform sprites are sometimes arranged in a 3-dimensional circular pattern, thus mapping the instantaneous electric field in the mesosphere.  相似文献   

WORK-PLACE UTILITIES AND COMMUTING PATTERNS: ARE THEY CLASS OR PLACE DIFFERENTIATED?*     

Baruch A. Kipnis  Yoel Mansfeld 《The Professional geographer》1986,38(2):160-169

The work-place utilities and commuting patterns of the employed in Haifa's (Israel) metropolitan field are analyzed using the value-stretch methodology. Statistical test scores reveal class and place (location) variations in the perceived utilities of employed, especially in their commuting patterns (flows). A meaningful commuting pattern analysis should incorporate socioeconomic and demographic elements along with the spatial distribution of job opportunities. Some analytical and policy implications of employment strategies for a postindustrial metropolis are evaluated.  相似文献   

Incipient metamorphism and deformation in the Variscides of SW Dyfed, Wales: first steps towards isotopic equilibrium   总被引：3，自引：0，他引：3  

D. J. SLATER  B. W. D. YARDLEY  B. SPIRO  R. J. KNIPE 《Journal of Metamorphic Geology》1994,12(3):237-248

Incipient metamorphism accompanying thrusting, folding and cleavage development has been investigated in a varied sequence of Palaeozoic sediments near the Variscan front in SW Dyfed, Wales. The aim was to evaluate a critical stage in the progression from heterogeneous sediment, whose detrital phases are neither in equilibrium with one another, nor with pore fluids, through indurated sedimentary rock to metamorphic rock comprising newly formed crystals that equilibrated with one another as they grew. Quartz veins are widely developed in the area, especially in the more psammitic lithologies, while finer grained rocks became cleaved during tectonic deformation. Mineralogical constraints and fluid inclusion measurements suggest maximum temperatures around 200-310d? C (slightly higher in the Marloes-Musselwick Thrust Sheet than in other parts of the structural succession) at depths of the order of 6-13 km. Quartz veins yield distinctly heavier oxygen isotopic compositions than detrital quartz grains in the adjacent wall rocks, although care must be taken in interpreting the data because slivers of detrital grains may become incorporated into veins, while matrix detrital grains may incorporate veinlets or rims of newly formed quartz. It is concluded that vein quartz grew in isotopic equilibrium with a fluid phase whose isotopic composition was primarily controlled by exchange with phyllosilicates, not detrital quartz grains. Vein and matrix quartzes from the Marloes-Musselwick Thrust Sheet are distinctly lighter (δ¹⁸O_veins=+14 to +18% and δ¹⁸O_matrix=+11 to +14%) than those from other thrust sheets (δ¹⁸O =+17 to +20% and +14 to +17%, respectively). We conclude that vein quartz and phyllosilicate grains in cleavage domains probably attained equilibrium with a locally buffered pore fluid at the peak of metamorphism, but many relict grains of different chemical and isotopic composition remained elsewhere in the rock. Local fluid migration along veins and through cleavage lamellae facilitated the attainment of equilibrium, but there is little evidence for large-scale infiltration of externally derived fluids. With further metamorphism the quartz in these rocks would attain an isotopic composition intermediate between that of the heavy vein material and light detritus which coexist here.  相似文献   

Biological marker characteristics of oils and asphalts from carbonate source rocks in a rapidly subsiding graben,Dead Sea,Israel     

Jürgen Rullkötter  Baruch Spiro  Arie Nissenbaum 《Geochimica et cosmochimica acta》1985,49(6):1357-1370

A detailed GC/MS study of biological marker compounds in the saturated and aromatic hydrocarbon fractions of oils and asphalts from the Dead Sea area, Israel, provided decisive information to the solution of a long-lasting controversy by showing that the asphalts are products of early generation in an immature stage from the same type of carbonate source rock which generated more mature oils. The asphalts are not biodegraded residues of the oils.Oils from six different wells, and asphalts from wells, outcrops, and a floating block from the Dead Sea all have very similar sterane and triterpane patterns. They all lack rearranged steranes (diasteranes) indicating a carbonate source matrix and compare reasonably well with a sample of Upper Cretaceous bituminous chalk from Nebi Musa. The main difference between the oils and the asphalts is a significantly higher triaromatic to mono- plus triaromatic steroid hydrocarbon ratio in the former. This is explained as a result of rapid subsidence and heating of their source rock close to the deep parts of the Dead Sea graben. The oils thus were generated in the more deeply buried source rock blocks under the graben fill, whereas the asphalts either originate from an immature source rock section closer to the graben rims or represent an earlier phase of generation and expulsion.This study also provides general information on the evolution of biological markers in carbonate source rocks. Low-activation-energy processes, like isomerisation of steranes, appear to occur much faster at low temperatures than in shales. The high sulfur content and less cross-linking of the biogenic organic matter into a complex kerogen structure are suggested to be responsible for this. Care should be taken when using only sterane isomerisation to assess the maturity of hydrocarbons from carbonate rocks and of carbonate-derived oils.  相似文献   

Role and timing of complementary objectives of a regional policy,the case of Northern Israel     

Baruch A. Kipnis 《Geoforum》1984,15(2):191-200

The lessons of a regional development policy for Northern Israel are evaluated. The policy has been led by two complementary objectives: the creation of a demographic balance in favour of Jews and the geographical development of a continuous network of Jewish settlements. Each objective had its appropriate spatial timing in the regional process. The first took advantage of geopolitical needs, ideological values and social conditions of the evolving nation during its pre-state and its early years. Attempts to reach the other objective through urban development programmes had failed until recently due to the strong polarization effects of Metropolitan Haifa. Starting in the mid 1970s, spontaneous metropolitan spread effects have created favourable conditions of growth. They have been reflected by both urban growth and massive rural development throughout the spillover effect area of the metropolis.  相似文献   

GEOGRAPHY IN ISRAEL     

Baruch Kipnis  Stanley Waterman 《The Professional geographer》1985,37(2):214-215

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Accretion disc evolution in cataclysmic variables (the 1988 international time project in La Palma     

P. A. Charles  M. J. Arévalo  J. Baruch  R. Biernicowicz  P. Callanan  J. Casares  V. Dhillon  A. Giménez  I. González  R. González  E. Harlaftis  B. Hassall  C. Hellier  P. Johnson  D. Jones  M. Kidger  C. Lázaro  K. Mason  K. Mukai  T. Naylor  V. Reglero  R. Rutten  J. L. Sedano  J. van Paradijs 《Astrophysics and Space Science》1990,169(1-2):147-148

A summary of data collected during a sixty night international campaign devoted to cataclysmic variables is presented.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献