Method for Validation of the Onboard Attitude Control System Software of the <Emphasis Type="Italic">Auriga</Emphasis> Earth Remote Sensing Small Spacecraft

The paper considers a digital modeling complex for the attitude control system of the Auriga Earth remote sensing small spacecraft. Mathematical models of measuring and executive devices are described. The results of spacecraft orbital attitude tests are presented.     

Radial velocity and magnetic field measurements of the a-type supergiant ν cep (HD 207260)

On the basis of 55 Zeeman spectrograms obtained at Tautenburg in the years 1975–1979 the effective magnetic fields and the radial velocities of the supergiant ν Cep (HD 207260) were determined. For the effective magnetic field a slow variation occurring on a time scale of years was found. The spectrograms taken at the first time show only moderate effective magnetic field strengths of a few hundred Gauß, but in the year 1978 values of +2000 Gauß were detected. The measured radial velocities show a longtime variability similar to that of the magnetic field as well as more rapid changes. A periodical variation of the radial velocity with a period of ∼ 39.9 days, perhaps produced by the rotation of the star, is indicated. The Balmer absorption lines H_β, H_β, and H_δ have different radial velocities refering to the presence of an expanding envelope. Moreover, there exist significant differences between the velocities of various elements respectively ions of 1–4 km/s.     

Lamprophyric lavas in the Colima graben,SW Mexico

The Colima graben, located in SW Mexico, is one of three grabens which intersect about 50 km SSW of Guadalajara, forming a triple junction. The 90 km long, 20–60 km wide Colima graben represents a N-S rift of the E-W trending Mexican Volcanic Belt. Since the Early Pliocene, the Colima graben has served as a locus for the eruption of alkaline lavas, the most recent of which are basanites and minettes erupted from Late Pleistocene cinder cones (Luhr and Carmichael 1981). In this paper, we report on older alkaline lavas which crop out in the graben's walls. These rocks include phlogopite- and hornblende-bearing lamprophyres, a phlogopite-kalsilite-ankaratrite, and high-K andesites. These lavas crop out throughout the Colima graben area, and are intimately associated with calc-alkaline lavas in the field. Compared to these, the alkaline rocks are strikingly enriched in the incompatible elements, particularly Ba, Sr, P, and the LREE. Unlike the younger Late Pleistocene alkaline cinder cone lavas, most of the graben wall lamprophyres and the high-K andesites represent magmas that appear to have undergone significant evolution since their generation, including fractionation, crustal contamination, and possible magma mixing. Least-squares modeling indicates that the cinder cone minettes represent reasonable parental magmas for the graben lamprophyres. The occurrence of these alkaline lavas in an active calc-alkaline volcanic arc is unusual, and we suggest that they are a manifestation of the rifting processes which produced the Colima graben.     

Some aspects of the succession and structure in the lower palaeozoic rocks of the southern uplands of scotland

Lower Palaeozoic successions in the Southern Uplands are much thicker than previously supposed and sedimentation may have lasted well into Ludlow times. Volcanic rocks are Arenig and Glenkiln in age and are often interbedded with greywackes and shales. Lapworth's concept of the structure as an anticlinorium and a synclinorium is rejected and it is suggested that the rocks have been folded into a series of compound monoclines which face north-westwards. These are probably cut by strike faults which bring up the older beds to the north.

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Zusammenfassung Die altpaläozoischen Schichtfolgen in den Südlichen Hochlanden sind viel mächtiger, als bisher angenommen wurde, und die Ablagerung kann bis ins Ludlow gereicht haben. Vulkanite haben Arenig- und Glenkiln-Alter; sie wechsellagern oft mit Grauwacken und Tonschiefern.Lapworths Vorstellung, der tektonische Bau sei ein Antiklinorium und ein Synklinorium, wird bestritten. Es wird angenommen, daß die Gesteine zu zusammengesetzten Monoklinen gefaltet wurden, deren steile Flügel nordwestwärts weisen. Sie werden wahrscheinlich durch streichende Verwerfungen zerschnitten, die die älteren Schichten im Norden herausheben.

     

Pseudoleucite in a Tinguaite from the Bearpaw Mountains, Montana

The article presents chemical analyses of the pseudoleuciteand groundmass of a pseudoleucite tinguaite, chemical analysesof the principal minerals, chemical estimates of the mode ofthe groundmass, and both chemical and micrometric modes of thepseudoleucite. The principal minerals are hedenbergitic acmite,a nepheline containing 2.3 per cent Fe₂O₃ and 7.9 per cent K₂O,and K-feldspar containing a little BaO and very little Na₂O.The micrometric mode of the pseudoleucite, in satisfactory agreementwith the chemical mode, is nepheline 29.8 per cent, K-feldspar66.2 per cent, acmite 3.0 per cent; the chemical mode of thegroundmass is nepheline 26.8 per cent, K-feldspar 46.6 per cent,and acmite 26.7 per cent. A new analysis of a nepheline fromthe Bancroft area, made to test the analytical procedure, isalso included.