INTEGRAL observations of the Small Magellanic Cloud     

V. A. McBride  M. J. Coe  A. J. Bird  A. J. Dean  A. B. Hill  K. E. McGowan  M. P. E. Schurch  A. Udalski  I. Soszynski  M. Finger  C. A. Wilson  R. H. D. Corbet  I. Negueruela 《Monthly notices of the Royal Astronomical Society》2007,382(2):743-749

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Clockwise rotations recorded in Early Cretaceous rocks of South Korea: implications for tectonic affinity between the Korean Peninsula and North China   总被引：12，自引：0，他引：12  

Xixi Zhao  Robert S. Coe  Ki-Hong Chang  Soon-Ok Park  Sheraz K. Omarzai  Rixiang Zhu  Yaoxiu Zhou  Stuart Gilder  & Zhong Zheng 《Geophysical Journal International》1999,139(2):447-463

Recent interest has focused on whether South Korea may have undergone variable tectonic rotations since the Cretaceous. In an effort to contribute to the answer to this question, we have completed a palaeomagnetic reconnaissance study of Early Cretaceous sedimentary and igneous rocks from the Kyongsang basin in southeast Korea. Stepwise thermal demagnetization isolated well-defined characteristic magnetization in all samples. The palaeomagnetic directions reveal patterns of increasing amounts of clockwise (CW) rotation with increasing age for Aptian rock units. Palaeomagnetic declinations indicate clockwise vertical-axis rotations of R = 34.3° ± 6.9° for the early Aptian rock unit, R = 24.9° ± 10.6° for the middle Aptian, and R = −0.9° ± 11.8° for the late Aptian relative to eastern Asia. The new Cretaceous palaeomagnetic data from this study are consistent with the hypothesis that Korea and other major parts of eastern Asia occupied the same relative positions in terms of palaeolatitudes in the Cretaceous. An analysis of and comparison with previously reported palaeomagnetic data corroborates this hypothesis and suggests that much of Korea may have been connected to the North China Block since the early Palaeozoic. A plausible cause of the rotation is the westward subduction of the Kula plate underneath the Asian continent, which is inferred to have occurred during the Cretaceous according to several geological and tectonic analyses.  相似文献   

The Be/X-ray transient V0332+53: evidence for a tilt between the orbit and the equatorial plane?     

I. Negueruela  P. Roche  J. Fabregat  M. J. Coe 《Monthly notices of the Royal Astronomical Society》1999,307(3):695-702

We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8–9Ve star, which places V0332+53 at a distance of ∼7 kpc. H α spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Owing to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital plane with respect to the circumstellar disc (presumably on the equatorial plane). Even though the periastron distance is only ≈10 R _*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically thick at optical and infrared wavelengths, which, together with its small size, is taken as an indication of tidal truncation.  相似文献   

The X-ray transient XTE J2012+381     

R. I. Hynes  P. Roche †  P. A. Charles  M. J. Coe 《Monthly notices of the Royal Astronomical Society》1999,305(3):L49-L53

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The Weybourne Atmospheric Observatory     

S. A. Penkett  J. M. C. Plane  F. J. Comes  K. C. Clemitshaw  H. Coe 《Journal of Atmospheric Chemistry》1999,33(2):107-110

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Observations of the Nitrate Radical in the Marine Boundary Layer   总被引：3，自引：0，他引：3  

B. J. Allan  N. Carslaw  H. Coe  R. A. Burgess  J. M. C. Plane 《Journal of Atmospheric Chemistry》1999,33(2):129-154

A study of the nitrate radical (NO3) has been conducted through a series of campaigns held at the Weybourne Atmospheric Observatory, located on the coast of north Norfolk, England. The NO3 concentration was measured in the lower boundary layer by the technique of differential optical absorption spectroscopy (DOAS). Although the set of observations is limited, seasonal patterns are apparent. In winter, the NO3 concentration in semi-polluted continental air masses was found to be of the order of 10 ppt, with an average turnover lifetime of 2.4 minutes. During summer in clean northerly air flows, the concentration was about 6 ppt with a lifetime of 7.2 minutes. The major loss mechanisms for the radical were investigated in some detail by employing a chemical box model, constrained by a suite of ancillary measurements. The model indicates that during the semi-polluted conditions experienced in winter, the major loss of NO3 occurred indirectly through reactions of N2O5, either in the gas-phase with H2O, or through uptake on aerosols. The most important direct loss was via reactions of NO3 with a number of unsaturated nonmethane hydrocarbons. The cleaner air masses observed during the summer were of marine origin and contained elevated concentrations of dimethyl sulfide (DMS), which provided the major loss route for NO3. The box model was then used to investigate the conditions in the remote marine boundary layer under which DMS will be oxidised more rapidly at night (by NO3) than during the day (by OH). This should occur if the concentration of NO2 is more than about 60% that of DMS.  相似文献   

Intercomparison of Formaldehyde Measurements in Clean and Polluted Atmospheres   总被引：2，自引：0，他引：2  

L. M. Cárdenas  D. J. Brassington  B. J. Allan  H. Coe  B. Alicke  Ulrich Platt  K. M. Wilson  J. M. C. Plane  S. A. Penkett 《Journal of Atmospheric Chemistry》2000,37(1):53-80

Three different techniques used tomeasure atmospheric formaldehyde were compared duringa field campaign carried out at a clean maritime siteon the West coast of Ireland. Two spectroscopictechniques Differential Optical AbsorptionSpectroscopy (DOAS) and Tunable Diode Laser AbsorptionSpectroscopy (TDLAS), together with a glass coil/Hantzschreaction/fluorescence technique, wereemployed for measurements of atmospheric formaldehydeof the order of a few hundred pptv. The betteragreement was observed between the fluorescence andDOAS instruments.Two DOAS instruments were compared to the glasscoil/Hantzsch reaction/fluorescence technique at asemi-polluted site on the North Norfolk coast, U.K.,where concentrations of formaldehyde were observed atlevels up to 4 ppbv. A very good agreement wasobserved between the two instruments.The glass coil/Hantzsch reaction/fluorescence and theTDLAS instruments were also deployed simultaneously inorder to measure indoor air inside a mobile laboratorylocated at the Imperial College Silwood Park site nearAscot, U.K. The doors of the mobile laboratory wereleft open in order to obtain the backgroundformaldehyde concentrations. Closing them afterwardsallowed us to observe the increase in concentrationsas a result of indoor emissions. The agreement betweenthe two instruments was outstanding (correlationcoefficient was 99%).The results from this study showed that of the fourinstruments included in this intercomparison the glasscoil/Hantzsch reaction/fluorescence technique provedthe most suitable for continuous measurements offormaldehyde in the background atmosphere.  相似文献   

Determination of Geomagnetic Palaeointensities in Vacuum     

Abdulwahab A. Khodair  Robert S. Coe 《Geophysical Journal International》1975,42(1):107-115

Summary. Specimens with low and intermediate Curie points from six Hawaiian historic basalt flows were used for the determination of the intensity of the historic geomagnetic field by the Thelliers' method. The specimens were heated either in air or in a vacuum of 10⁻⁵ torr. The regional intensity of the Earth's magnetic field at the time of extrusion of these rocks is known from direct observations. The palaeointensities determined in vacuum from four low and intermediate Curie point flows are correct within the uncertainty caused by the local field anomalies, whereas those determined in air from the same four flows are of lesser quality and accuracy. Unaltered submarine basalts have similarly low Curie points and thus may also be amenable to palaeointensity determination in vacuum. The behaviour of the remaining two flows, which had higher Curie points, was more erratic, and they yielded less accurate palaeointensities regardless of whether they were determined in air or vacuum.  相似文献   

Magma generated structures and their subsequent development in the Late Archaean evolution of Northern Buksefjorden,Southern West Greenland     

Dr. Brian Chadwick  K. Coe  J. G. Stainforth 《International Journal of Earth Sciences》1982,71(1):61-72

The Inugssugssuaq nappe is made up of a membrane of anorthositic rocks sheathed by grey gneisses of Nûk age (2.800 Ma) and with a core of highly xenolithic Nûk grey gneiss. The structure was generated by magmatic diapirism followed by tectonic activity, but both stages probably resulted from thermally induced gravitational instability. Relations with geometrically similar structures in the area are discussed.

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Zusammenfassung Die Inugssugssuaq-Decke wird durch eine Membran von anorthositischen Gesteinen aufgebaut, die durch graue Gneise von Nûk Alter (2.800 Ma) eingehüllt wird und die einen Kern aus grauem, stark xenolithischen Gneis besitzt.Die Struktur wurde durch magmatischen Diapirismus gebildet, gefolgt von tektonischer Aktivität. Beide Stadien waren wahrscheinlich die Folge thermisch verursachter Schwereinstabilität. Die Beziehungen zu geometrisch ähnlichen Strukturen in dem Gebiet werden diskutiert.

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Résumé La nappe d'Inugssugssuaq est formée par une membrane de roches anorthositiques, enrobée par des gneiss d âge Nuk (2.800 Ma), avec un noyau de gneiss xénolithiques gris.La structure résulte d'un diapirisme magmatique auquel a succédé une activité tectonique. Ces deux étappes furent vraisemblablement la conséquence d'une instabilité gravitative d'origine thermique. Les relations avec des structures géométriques semblables dans la région sont discutées.

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Inugssugssuaq , (2.800 ), . , . , , . .

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Record of the younger part of the Pringle Falls excursion at Long Valley, California     

Joseph C. Liddicoat  Robert S. Coe  & Jonathan M. Glen 《Geophysical Journal International》1998,135(2):663-670

The younger of two closely spaced palaeomagnetic excursions at Pringle Falls, Oregon, is recorded in lacustrine silts that crop out in Long Valley, California. Assigned an age of about 220 000 years, the virtual geomagnetic poles of the younger excursion form a clockwise loop that reached 35 °S latitude east of South America before returning to the northern hemisphere in the Pacific Ocean west of Central America. The poles then form a narrow band across North America while moving to high northern latitudes. This record matches extremely well feature B of the original excursion record from Pringle Falls reported by Herrero-Bervera et al. (1994) and is similar to this excursion at Summer Lake, Oregon ( Negrini et al. 1994 ), in that the pole path is confined primarily to the east–central Pacific Ocean. On the basis of an assumed sedimentation rate of 30  cm per thousand years, the younger excursion (feature B at Pringle Falls) spans an estimated 1200 years and followed by about 1000 years a larger excursion (feature A at Pringle Falls) previously discovered at the same Long Valley site. At a second Long Valley site 30  m away, the younger excursion (feature B) is only partially recorded because of a presumed small hiatus in the sedimentary section.  相似文献