Simultaneous measurements of Martian plasma boundaries by Rosetta and Mars Express

We present the first two-spacecraft near-simultaneous observations of the Martian bow shock (BS), magnetic pileup boundary (MPB) and photo-electron boundary (PEB) obtained by the plasma instruments onboard Rosetta and Mars Express during the Rosetta Mars flyby on February 25, 2007. Our observations are compared with shape models for the BS and MPB derived from previous statistical studies. The MPB is found at its expected position but the BS for this event is found significantly closer to the planet than expected for the rather slow and moderately dense solar wind. Cross-calibration of the density measurements on the two spacecraft gives a density profile through the magnetosheath, indicating an increasing solar wind flux during the Rosetta passage which is consistent with the multiple BS crossings at the Rosetta exit.     

Late Holocene (0–2.4 ka BP) surface water temperature and salinity variability, Feni Drift, NE Atlantic Ocean

Planktonic foraminiferal Mg/Ca ratios and oxygen isotopic compositions of a spliced sediment record from Feni Drift, NE Atlantic Ocean (box core M200309 and piston core ENAM9606) trace late Holocene sea surface temperature (SST) and salinity changes over the past 2400 years. At this location, the variability of SST and oxygen isotopic composition of seawater (δ¹⁸O_w) reflects variable northward advection of warm and saline surface waters, which appears linked to climate variability over the adjacent European continent. Our records reveal a general long-term cooling trend. Superimposed on this overall trend, partly higher temperatures and salinities from 180 to 560 AD and 750 to 1160 AD may be ascribed to the Roman and Medieval Warm Periods, respectively. Subsequently, our record displays highly variable surface water conditions; the main Little Ice Age SST minimum is restricted to the 15th and 16th centuries AD. Pervasive multidecadal- to centennial-scale variability throughout the sedimentary proxy records can be partly attributed to solar forcing and/or variable heat extraction from the surface ocean caused by shifts in the prevailing state of the North Atlantic Oscillation (NAO). High salinities in the 17th and 18th centuries are considered to reflect tropical anomalies linked to a southward shift of the Intertropical Convergence Zone, propagating across the North Atlantic Ocean.     

Mass Fractions of Forty‐Six Major and Trace Elements,Including Rare Earth Elements,in Sediment and Soil Reference Materials Used in Environmental Studies

Development of new techniques, enabling simultaneous determination of large numbers of elements in environmental samples, can force analysts to use certified reference materials that do not contain all the elements of interest. In this paper, the mass fractions of forty‐six major and trace elements, including rare earth elements (REE), are presented in one soil (NCS DC 77302 also known as GBW 07410) and five sediment (Metranal‐1, IAEA 405, MESS‐3, NCS DC 73309 also known as GBW 07311 and NCS DC 75301 also known as GBW 07314) certified reference materials determined by high resolution inductively coupled plasma‐mass spectrometry. The selected certified materials represent a spectrum of geological matrices often analysed in environmental studies. Measured elements include certified elements, elements listed with information values as well as new elements absent from certificates, including REEs and some other elements. REE + Y mass fractions in the river sediment reference material Metranal‐1 are reported for the first time. The results obtained are in agreement with available certified or information values.     

Wave-trains in the solar wind

The equations of motion of all relevant parameters of Alfvén waves propagating from the sun outwardly into the expanding interplanetary medium are discussed for the case of a quiet, ideal, isotropic, one-fluid solar wind plasma. It is found that the frequency of the wave reamains constant, while the wave vector and the amplitudes depend, in general, on the evolution of the background medium and on the angle between the wave vector and the interplanetary magnetic field. This latter dependence cancels approximately for the evolution of the amplitudes in the case of a pure, overall spiral magnetic field. It is shown that in this case the results of earlier discussions can be derived by less decisive restrictions.     

Epigenetic dolomitization of the Přaídolí formation (Upper Silurian), the Barrandian basin,Czech Republic: implications for burial history of Lower Paleozoic strata

Stratabound epigenetic dolomite occurs in carbonate facies of the Barrandian basin (Silurian and Devonian), Czech Republic. The most intense dolomitization is developed in bioclastic calcarenites within the transition between micritic limestone and shaledominated Přídolí and Lochkov formations deposited on a carbonate slope. Medium-crystalline (100–400 μm), inclusion-rich, xenotopic matrix dolomite (δ ¹⁸O=−4.64 to −3.40‰ PDB;δ ¹³C=+1.05 to +1.85‰ PDB) which selectively replaced most of the bioclastic precursor is volumetrically the most important dolomite type. Coarse crystalline saddle dolomite (δ ¹⁸O=−8.04 to −5.14‰ PDB;δ ¹⁸C=+0.49 to +1.49 PDB) which precipitated in fractures and vugs within the matrix dolomite represents a later diagenetic dolomitization event. In some vugs, saddle dolomite coprecipitated with petroleum inclusion-rich authigenic quartz crystals and minor sulfides which, in turn, were post-dated by semisolid asphaltic bitumen. The interpretation of the dolomitization remains equivocal. Massive xenotopic dolomite, although generally characteristic of a deeper burial setting, may have been formed by a recrystallization of an earlier, possibly shallow burial dolomite. Deeper burial recrystallization by reactive basinal pore fluids that presumably migrated through the more permeable upper portion of the Přídolí sequence appears as a viable explanation for this dolomitization overprint. Saddle dolomite cement of the matrix dolomite is interpreted as the last dolomitization event that occurred during deep burial at the depth of the oil window zone. The presence of saddle dolomite, the fluid inclusion composition of associated quartz crystals, and vitrinite paleogeothermometry of adjacent sediments imply diagenetic burial temperatures as high as 160°C. Although high geothermal gradients in the past or the involvement of hydrothermally influenced basinal fluids can account for these elevated temperatures, burial heating beneath approximately 3-km-thick sedimentary overburden of presumably post-Givetian strata, no longer preserved in the basin, appears to be the most likely interpretation. This interpretaion may imply that the magnitude of post-Variscan erosion in the Barrandian area was substantially greater than previously thought.     

Kutnohorite from the Chvaletice pyrite and manganese deposit,east Bohemia

Summary Kutnohorite-quartz veins penetrate through a weakly metamorphosed Late Proterozoic sedimentary rhodochrosite carbonate in pyrite shales. Kutnohorite is pleochroic ranging from colourless () to pinkish grey (), =1.735, =1,543,d=3.066g·cm^–3;a ₀=4.852(1),c ₀=16.219(7) Å. A quantitative chemical analysis leads to the formula (Ca_0.95Mn_0.05)_1.00(Mn_0.64Mg_0.23Fe_0.13)_1.00(CO₃)_2.04. An electron microprobe scanning reveals considerable microscale inhomogeneity in cleavage rhombohedrons taken from a coarsely grained aggregate. It is mostly of the character of periodic fluctuations of the main element contents around an average value. There is a strong prevalence of an Fe+Ca–Mn+Mg antagonism, the extremes of compositonal differences lying in distances of 0.0X mm. The fluctuation maxima amount to about 9% for FeO, 6% for MnO, 3% for CaO, and 1.5% for MgO. In one of the samples even a two phase character with the above antagonism between the two phases was detected by X-rays. The inhomogeneities are due, partly at least, to the Fe-metasomatic processes that followed the formation of the kutnohorite by Alpine-paragenesis hydrothermal metamorphism.

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Kutnohorit aus der Pyrit-und Manganlagerstätte von Chvaletice (Ostböhmen)

Zusammenfassung Kutnohorit-Quarzgänge durchdringen ein schwach metamorphes jungproterozoisches sedimentäres Rhodochrositkarbonat in pyritischen Schiefern. Der Pleochroismus von Kutnohorit liegt zwischen farblos () und rosagrau (), =1,735, =1,543;d=3,066 g·cm^–3;a ₀=4,852(1),c ₀=16,219(7) Å. Die quantitative chemische Analyse des Minerals ergibt Formel (Ca_0,95Mn_0,05)_1,00(Mn_0,64Mg_0,23Fe_0,13)_1,00(CO₃)_2,04. Elektronenmikrosondenuntersuchungen zeigen eine starke mikroskopische Inhomogenität in den Spaltrhomboedern von einem grobkörnigen Kutnohoritaggregat. Sie ist meistens durch periodische Schwankungen der Hauptelementgehalte um einen Mittelwert hervorgerufen. Antagonistische Beziehungen von Fe+Ca und Mn+Mg überwiegen, die extremen Werte von Elementgehalten liegen in Abständen von 0,0X mm. Die höchsten Schwankungen erreichen etwa 9% für FeO, 6% für MnO, 3% für CaO und 1,5% für MgO. In einer Probe konnten röntgenographisch sogar zwei Kutnohoritphasen mit dem erwähnten Antagonismus zwischen den Phasen bewiesen werden. Die Inhomogenitäten wurden wahrscheinlich meistens durch Fe-metasomatische Vorgänge nach der Kristallisation des Kutnohorits während der hydrothermalmetamorphen Prozesse der Alpinen Paragenese hervorgerufen.

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With 4 Figures     

Beziehungen zwischen Ligurischen Alpen und Nordapennin

Zusammenfassung Der nördliche Teil der ligurischen Alpen zieht zwischen Ronco und Genua nur scheinbar in den südwestlichen Teil des Nordapennin hinein. Beim Verfolgen der westalpinen tektonischen Serien stellt man fest, daß keine alpine Einheit in den Nordapennin eintritt, dessen Gesteine vielmehr einem eigenen ligurischen Trog entstammen und der in den Hügeln von Turin sich fortsetzt. Westalpen und Apennin laufen hier aneinander vorbei. Der eigenständige ligurische Trog liegt zwischen Südalpin und Hochpenninikum in einem Bereich, der in den Alpen (Graubünden) zum unterostalpinen Gebiet wird. Die Frage nach einem Deckenbau im Nordapennin bleibt offen infolge der starken Diapirfaltung der Argille scagliose und der daraus entstehenden wechselnden Vergenzen. Es wird ein Vergleich der Flyschmassen vom Embrunais und Ubaye über die ligurischen Alpen bis zum Nordapennin durchgeführt und zuletzt auf das Alter der Bewegungen und die bis heute fortschreitende Faltung im Südteil der Poebene eingegangen.     

Gesteine und Vorkommen der Arosa-Zone Zwischen Arosa und Hindelang im Allgäu

Ohne Zusammenfassung