Tectonic setting of basic volcanic rocks determined using trace element analyses   总被引：23，自引：0，他引：23  

J.A. Pearce  J.R. Cann 《Earth and Planetary Science Letters》1973,19(2):290-300

Analyses for Ti, Zr, Y, Nb and Sr in over 200 basaltic rocks from different tectonic settings have been used to construct diagrams in which these settings can usually be identified. Basalts erupted within plates (ocean island and continental basalts) can be identified using a Ti-Zr-Y diagram, ocean-floor basalts, and low-potassium tholeiites and calc-alkali basalts from island arcs can be identified using a Ti-Zr diagram (for altered samples) and a Ti-Zr-Sr diagram (for fresh samples). Y/Nb is suggested as a parameter for indicating whether a basalt is of tholeiitic or alkalic nature. Analyses of dykes and pillow lavas from the Troodos Massif of Cyprus are plotted on these diagrams and appear to the tholeiitic ocean-floor rocks.  相似文献   

Infrared emission from interstellar grains heated by supernovae     

G. Pearce  A. Evans 《Astrophysics and Space Science》1983,96(1):159-170

The infrared emission from interstellar grains heated by a supernova in eruption is investigated. The dependence of the emission on various physical parameters, such as the depth of the supernova into the dust plane of the parent galaxy, the inclination of the galaxy to the line-of-sight, are investigated. The possibility of detecting this emission is discussed. The prospects are hopeful as far as cryogenically-cooled instruments in Earth orbit are concerned.  相似文献   

The relationship between major element chemistry and tectonic environment of basic and intermediate volcanic rocks   总被引：2，自引：0，他引：2  

T.H. Pearce  B.E. Gorman  T.C. Birkett 《Earth and Planetary Science Letters》1977,36(1):121-132

This work reports the preliminary results of a study of the relationship between tectonic environment and major element chemistry of volcanic rocks. Using a file of 8400 analyses of rocks of varying ages and geographic distribution it has been found that a simple ternary plot of MgOFeO(total)Al₂O₃ may be used to distinguish five tectonic environments: ocean ridge and floor, ocean island, continental, orogenic, and spreading center island. Subalkaline “basaltic-andesites” (51–56% SiO₂ calculated anhydrous) are used in this study. Alkaline rocks do not generally show the simple patterns of tholeiitic or subalkaline rocks. The ocean island suite is bimodal with one mode tholeiitic and the other alkaline. A bimodal age/chemistry relationship in the continental suite is tentatively related to different conditions during and after active breaking up of continents (rifting and drifting stages).Most of the Archean rocks in our file generally do not fall in the orogenic field. It is unlikely that modern island arc models can be generally applied to Archean greenstone belts. Locally, however, there may be Archean rocks analogous in some respect to modern calc-alkali rocks.  相似文献   

The design and flight performance of the PoGOLite Pathfinder balloon-borne hard X-ray polarimeter     

M. Chauvin  H.-G. Florén  M. Jackson  T. Kamae  T. Kawano  M. Kiss  M. Kole  V. Mikhalev  E. Moretti  G. Olofsson  S. Rydström  H. Takahashi  J. Lind  J.-E. Strömberg  O. Welin  A. Iyudin  D. Shifrin  M. Pearce 《Experimental Astronomy》2016,41(1-2):17-41

In the 50 years since the advent of X-ray astronomy there have been many scientific advances due to the development of new experimental techniques for detecting and characterising X-rays. Observations of X-ray polarisation have, however, not undergone a similar development. This is a shortcoming since a plethora of open questions related to the nature of X-ray sources could be resolved through measurements of the linear polarisation of emitted X-rays. The PoGOLite Pathfinder is a balloon-borne hard X-ray polarimeter operating in the 25-240 keV energy band from a stabilised observation platform. Polarisation is determined using coincident energy deposits in a segmented array of plastic scintillators surrounded by a BGO anticoincidence system and a polyethylene neutron shield. The PoGOLite Pathfinder was launched from the SSC Esrange Space Centre in July 2013. A near-circumpolar flight was achieved with a duration of approximately two weeks. The flight performance of the Pathfinder design is discussed for the three Crab observations conducted. The signal-to-background ratio for the observations is shown to be 0.25 ±0.03 and the Minimum Detectable Polarisation (99 % C.L.) is (28.4 ±2.2) %. A strategy for the continuation of the PoGOLite programme is outlined based on experience gained during the 2013 maiden flight.  相似文献   

Primordial non-Gaussianity from LAMOST surveys     

Yan Gong    Xin Wang  Zheng Zheng  Xue-Lei Chen    National Astronomical Observatories  Chinese Academy of Sciences  Beijing  China  Graduate University of Chinese Academy of Sciences  Beijing  China Institute for Advanced Study  Einstein Drive  Princeton  NJ  USA Center of High Energy Physics  Peking University  Beijing  China Kavli Institute for Theoretical Physics China  CAS  Beijing 《中国天文和天体物理学报》2010,10(2)

The primordial non-Gaussianity (PNG) in the matter density perturbation is a very powerful probe of the physics of the very early Universe. The local PNG can induce a distinct scale-dependent bias on the large scale structure distribution of galaxies and quasars, which could be used for constraining it. We study the detection limits of PNG from the surveys of the LAMOST telescope. The cases of the main galaxy survey, the luminous red galaxy (LRG) survey, and the quasar survey of dif- ferent magnitude limits...  相似文献   

Revisiting the cosmic cooling crisis     

Michael L. Balogh  Frazer R. Pearce  Richard G. Bower  Scott T. Kay 《Monthly notices of the Royal Astronomical Society》2001,326(4):1228-1234

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Including star formation and supernova feedback within cosmological simulations of galaxy formation   总被引：1，自引：0，他引：1  

Scott T.Kay  Frazer R.Pearce  Carlos S.Frenk  AdrianJenkins 《Monthly notices of the Royal Astronomical Society》2002,330(1):113-128

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The seismic disturbance of 1976 March 20, elast Kazakhstan: earthquake or explosions?     

C.I. Pooley  A. Douglas  R. G. Pearce 《Geophysical Journal International》1983,74(2):621-631

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An Infra-Red model of the zodiacal emission     

J. Tigg  G. Pearce 《Earth, Moon, and Planets》1988,43(2):101-105

The Infra-Red Astronomical Satellite (IRAS) observations of the zodiacal dust emission are used to fit the dust grain composition and distribution in the ecliptical plane. We obtain a good fit to the data for a density distribution of black-body grains given by p = pr ^{0.66/log(1.7r/R)} for r < 0.87R and r < 3oR  相似文献   

A fault plane solution using theoretical P seismograms   总被引：1，自引：0，他引：1  

B. J. Barley  R. G. Pearce 《Geophysical Journal International》1977,51(3):653-668

We use the method of Hudson and Douglas, Hudson & Blarney to compute seismograms which simulate the codas of 10 short period P -wave seismograms from a shallow earthquake. The polarities and relative amplitudes of P and pP measured from seven of the observed seismograms are used to compute a fault plane solution with confidence limits, assuming that the source radiates as a double couple. This solution is in approximate agreement with that given for the same earthquake by Sykes & Sbar, who used only the onset polarities of short-period P waves. The small difference between the two solutions can be explained by interference between the true first motion of P and microseismic noise at two stations.
The results show that, for some shallow earthquakes, the relative amplitude method has the following advantages over the first motions method. First, a P/pP amplitude ratio (with appropriate confidence limits) can always be measured, even in seismograms which are so noisy that the first motion of P is uncertain. Second, the fault plane solutions obtained from relative amplitudes have known confidence limits. Finally, by using more information from each seismogram, the relative amplitude method requires considerably fewer seismograms than the first motions method.  相似文献