Detectives and geology in fiction - 2: After the Golden Age     

WILLIAM A. S. SARJEANT 《Geology Today》1995,11(2):68-72

Following the'Golden Age'of Holmes and Thorndyke, geology and geological phenomena have figured in quite a number of crime novels. In a handful, geologists even serve as central characters — or as victims. These novels are here identified and briefly discussed, while the lack of a geologist as 'series character'is lamented.  相似文献   

ESTIMATION IN COMPOSITIONAL DATA ANALYSIS     

WILLIAMS.RAYENS  CIDAMBISRINIVASAN 《地理学报(英文版)》1991,(4)

Compositional data arise naturally in several branches of science,including chemistry,geology,biology,medicine,ecology and manufacturing design.In chemistry,these constrained data seem to occur typicallywhen raw data are normalized or when output is obtained from a constrained estimation procedure,suchas might be used in a source apportionment problem.It is important not only for chemists to be awarethat the usual multivariate statistical techniques are not applicable to constrained data,but also to haveaccess to appropriate techniques as they become available.The currently available methodology is dueprincipally to Aitchison and is based on log-normal models.This paper suggests new parametric andnon-parametric approaches to significantly improve the existing methodology.In the parametric setting,some recent work of Rayens and Srinivasan is extended and a practical regression model is proposed.In the development of the non-parametric approach,minimum distance methods coupled withmultivariate bootstrap techniques are used to obtain point and region estimators.  相似文献   

Palaeontology in the NCC     

DAVID B. NORMAN  WILLIAM A. WIMBLEDON 《Geology Today》1988,4(6):194-196

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EDWARD BELLAMY AND THE WEATHER OF UTOPIA     

WILLIAM B. MEYER 《Geographical review》2004,94(1):43-54

ABSTRACT. Utopian thinkers have often assumed that radical geoengineering is necessary for the creation of a perfect world. This assumption necessarily puts them at odds with environmentalism, but the conflict is not inescapable. Human difficulties with the biophysical world can instead be interpreted as arising from the interaction of environment with society and thus as capable of being eradicated simply by reforming the latter. One notable early exponent of this kind of social constructionism was the American utopian novelist and publicist Edward Bellamy (1850–1898). His fictional and nonfictional writings analyzed the ways in which the troubles that Americans of his time had with weather and climate grew out of their ways of life and political‐economic institutions and would disappear if these were reformed. This line of thought allowed Bellamy to portray a utopia where human beings had ceased to suffer serious harm and inconvenience from the weather yet had not tampered with the atmospheric environment itself.  相似文献   

Ultra-calcic Magmas Generated from Ca-depleted Mantle: an Experimental Study on the Origin of Ankaramites   总被引：3，自引：1，他引：3  

SCHMIDT  MAX W.; GREEN  DAVID H.; HIBBERSON  WILLIAM O. 《Journal of Petrology》2004,45(3):531-554

Ultra-calcic ankaramitic magmas or melt inclusions are ubiquitousin arc, ocean-island and mid-ocean ridge settings. They areprimitive in character (X_Mg > 0·65) and have highCaO contents (>14 wt %) and CaO/Al₂O₃ (>1·1). Experimentson an ankaramite from Epi, Vanuatu arc, demonstrate that itsliquidus surface has only clinopyroxene at pressures of 15 and20 kbar, with X_CO2 in the volatile component from 0 to 0·86.The parental Epi ankaramite is thus not an unfractionated magma.However, forcing the ankaramite experimentally into saturationwith olivine, orthopyroxene and spinel results in more magnesian,ultra-calcic melts with CaO/Al₂O₃ of 1·21–1·58.The experimental melts are not extremely Ca-rich but high inCaO/Al₂O₃ and in MgO (up to 18.5 wt %), and would evolve tohigh-CaO melts through olivine fractionation. Fractionationmodels show that the Epi parent magma can be derived from suchultra-calcic experimental melts through mainly olivine fractionation.We show that the experimental ultra-calcic melts could formthrough low-degree melting of somewhat refractory mantle. Thelatter would have been depleted by previous melt extraction,which increases the CaO/Al₂O₃ in the residue as long as someclinopyroxene remains residual. This finding corrects the commonassumption that ultra-calcic magmas must come from a Ca-richpyroxenite-type source. The temperatures necessary for the generationof ultra-calcic magmas are  相似文献   

Monazite-Xenotime-Garnet Equilibrium in Metapelites and a New Monazite-Garnet Thermometer   总被引：9，自引：0，他引：9  

PYLE  JOSEPH M.; SPEAR  FRANK S.; RUDNICK  ROBERTA L.; McDONOUGH  WILLIAM F. 《Journal of Petrology》2001,42(11):2083-2107

Prograde suites of pelitic rocks were examined with electronmicroprobe and laser ablation inductively coupled plasma massspectrometry to determine the systematics of element partitioningbetween coexisting monazite, xenotime, and garnet. Monazitegrains that grew in equilibrium with xenotime are enriched inY and Dy compared with monazite that grew in xenotime-absentassemblages. Y and heavy rare earth element contents of monazitecoexisting with xenotime increase with rising temperature. Monazite–xenotimeY–Gd and Y–Dy partitioning is systematic withina metamorphic grade, and increases slightly with increasingmetamorphic grade, suggesting that monazite–xenotime pairsapproached partitioning equilibrium. Garnet and monazite inboth xenotime-bearing and xenotime-absent assemblages show astrong ( R² = 0·94) systematic relationship between inversetemperature and ln(K_Eq) for the net-transfer equilibrium YAG+ OH-Ap + (25/4)Qtz = (5/4)Grs + (5/4)An + 3YPO₄-Mnz + 1/2H₂O,suggesting that garnet and monazite crystallized in compositionalequilibrium. The following temperature–K_Eq relationshipfor the equilibrium above has been derived:   相似文献   

New Zealand in the Post Cold-War World     

WILLIAM W. HARRIS 《New Zealand geographer》1993,49(2):7-12

Abstract. The paper examines political and economic aspects of New Zealand's position in the world in the aftermath of the Cold War. It stresses the need for a balanced approach to the country's connections with the major power centres of the capitalist West, in an emerging multipolar geopolitical environment. It warns against disproportionate enthusiasms for particular places or concepts. New Zealand's national identity and interests have a distinctive South Pacific bicultural context, and this has a strong relevance for New Zealand's international profile, especially in relation to Australia.  相似文献   

Modern and Holocene carbonate sedimentology of two saline volcanic maar lakes, southern Australia   总被引：4，自引：0，他引：4  

WILLIAM M. LAST  PATRICK DE  DECKKER† 《Sedimentology》1990,37(6):967-981

The Basin Lakes are two adjacent maar lakes located in the centre of the Western Volcanic Plains District of Victoria, Australia. Both lakes are saline and alkaline; West Basin Lake is meromictic whereas East Basin is a warm monomictic lake. The carbonate mineral suite of the modern offshore bottom sediments of these Basins consists mainly of dolomite and calcite, with smaller amounts of hydromagnesite and magnesite in West Basin and monohydrocalcite in East Basin. The dolomite, hydromagnesite, magnesite, and monohydrocalcite are endogenic in origin, being derived by primary inorganic precipitation within the water columns of the lakes or at the sediment-water interface. The calcite is biologically precipitated as ostracod valves. In addition to the carbonates in the modern offshore (deep-water) sediments, the lakes also contain a girdle of nearshore carbonate hardgrounds. Both beachrock and microbialites (algal boundstones) are present. These modern lithified carbonate units exhibit a wide range of depositional and diagenetic fabrics, morphologies and compositions. In West Basin, the hardgrounds are composed mainly of dolomite, hydromagnesite, and magnesite, whereas dolomite and monohydrocalcite dominate the East Basin sediments. Aragonite, high-Mg calcite, kutnahorite, siderite, and protohydromagnesite also occur in these lithified carbonate units. Stratigraphic variations in the carbonate mineralogy of the Holocene sediment record in the lakes were used to help decipher the palaeochemistry and palaeohydrology of the Basins. These changes, in conjunction with fluctuations in organic remains and fossil content, indicate a pattern of lake level histories similar to that deciphered from other maar lakes in western Victoria.  相似文献   

Geochemistry and origin of a black mudstone in a volcaniclastic environment, Ordovician Lower Rhyolitic Tuff Formation, North Wales, UK   总被引：1，自引：0，他引：1  

WILLIAM J. FRITZ  DAVID A. VANKO 《Sedimentology》1992,39(4):663-674

Black mudstones in marine volcaniclastic environments have been interpreted both as non-volcanic ‘background’sedimentation and as fine grained vitric dust from the waning stages of primary volcanism. Although difficult to distinguish by standard petrographic techniques, differentiation between the two is crucial when attempting to determine sedimentation rates or to infer periods of volcanic quiescence. In the Ordovician Lower Rhyolitic Tuff Formation of North Wales such a fine grained black unit at Cwm Idwal is geochemically similar to an underlying rhyolite ash flow tuff. Its chemical index of alteration (CIA) is identical to that of the tuff. These data suggest that the black mudstone unit is a vitric tuff related to the underlying ash flow tuff. Use of a CIA in addition to trace element geochemistry should, in most cases, serve to distinguish tuffs from silicified mudstones.  相似文献   

Flow properties of turbidity currents in Bute Inlet, British Columbia   总被引：1，自引：0，他引：1  

JIANJUN ZENG  DONALD R. LOWE  DAVID B. PRIOR  WILLIAM J. WISEMAN  JR  BRIAN D. BORNHOLD 《Sedimentology》1991,38(6):975-996

Bute Inlet, a fiord along the southwestern coast of British Columbia, Canada, includes a sea-floor sedimentation system 70 km in length which resembles those developed on some large submarine fans. Turbidity currents originate at the head of the flord on the submerged delta fronts of the Homathko and Southgate rivers. They move downslope for about 30 km within a single large incised channel, spill onto a depositional area termed the channel lobe complex, and finally spread out over a low-relief distal splay area that passes 55 km downslope into a flat basin floor. During the present study, turbidity currents in Bute Inlet were studied using sea-floor morphology, bottom sediment distribution, and in-situ instrument packages. The mean velocities of the most recent flows, estimated from surface sediment grain size, has varied between 100–120 cm s^–1 in the incised channel, 20–50 cms^–1 in the channel lobe complex, and < 5 cm s^–1 on the basin floor. Velocities based on channel morphology are poorly constrained but are in the range of 160-425 cm s^–1 in the upper part of the incised channel and 66 cm s^–1 in the lower channel. Calculated flow densities range from 1.049 to 1.028g cm^–3. Turbidity flows monitored in 1986 using submerged instrument packages exceeded 32 m in thickness in the upper part of the incised channel, where the maximum measured velocity was 330 cm s^–1. At the head of the channel lobe complex the maximum velocity had declined to 75 cm s^–1. The density of the monitored flows is estimated at 1.025-1.03g cm^–3. The cored sediments and channel morphology yield estimates of mean flow velocities that are generally greater than those measured by the in-situ instrument packages and estimated from modern surface sediments. The former suggest past flow velocities up to 500 cm s^–1 in the incised channel, about 20 cm s^–1 in spillover deposits along the lower part of the incised channel, and 100-140 cm s^–1 in the distal splay. The contrast between the velocities of modern and past flows suggests that past flows may have been considerably larger and more energetic than those presently occurring in Bute Inlet. The size properties of sediments in the monitored turbidity flows suggest a strong vertical size gradient in the suspended load during transport. The surface and cored sediments fine downslope from the channel lobe complex to distal splay area. Distinctive sedimentary sequences are recognized in cores from the spillover lobes, channel lobe complex, distal splay, and basin floor depositional areas. Many individual turbidites grade downslope from massive T_a divisions in the channel lobe complex and probably in the incised channel to T_a divisions overlain by slurried divisions on the distal splay and largely slurried beds on the basin floor. These facies suggest that individual currents commonly evolve from largely cohesionless suspensions in the incised channel and channel lobe complex to dilute cohesive slurries downslope on the distal splay and basin floor. Many flows in Bute Inlet fail to develop a traction state of sedimentation and the resulting turbidites lack well-developed T_b. T_c, and T_d divisions.  相似文献