Diradicaloids in the insoluble organic matter from the Tagish Lake meteorite: Comparison with the Orgueil and Murchison meteorites

Abstract— The radicals in the insoluble organic matter (IOM) from the Tagish Lake meteorite were studied by electron paramagnetic resonance and compared to those existing in the Orgueil and Murchison meteorites. As in the Orgueil and Murchison meteorites, the radicals in the Tagish Lake meteorite are heterogeneously distributed and comprise a substantial amount (?42%) of species with a thermally accessible triplet state and with the same singlet‐triplet gap, ΔE ?0.1 eV, as in the Orgueil and Murchison meteorites. These species were identified as diradicaloid moieties. The existence of similar diradicaloid moieties in three different carbonaceous chondrites but not in terrestrial IOM strongly suggests that these moieties could be “fingerprints” of the extraterrestrial origin of meteoritic IOM and markers of its synthetic pathway before its inclusion into a parent body.     

Late-glacial varved clays in the Bornholm Basin and Hanö Bay

Distribution, thickness, lithology and stratigraphy of varved clays are discussed. The sediments were deposited in the Baltic Ice Lake during the Late Weichselian.     

Deglaciation of the Bara Basin near Malmö, Sweden

Results obtained by mapping and special varved clay investigation show that the so-called Northeastern ice advance (13,500 B.P.) and the Low Baltic readvance (13,000–13,200 B.P.) are separated by a significant deglaciation phase, for which we propose 'Lockarp Interstadial' (13,200-13,500 B.P.) as a time-stratigraphic term to be used in the type area of southwestern Scania.     

激光剥蚀-等离子体质谱技术及其在地球化学宇宙化学和环境研究中的应用

激光剥蚀-等离子体质谱(LA-ICPMS)已成为地球化学、宇宙化学和环境研究领域元素和同位素原位分析最重要的技术之一。文章介绍了多种类型的质谱仪及其使用的激光器。用途最广的LA-ICPMS仪器之一是单接收器扇形磁场质谱仪,配有Nd:YAG激光剥蚀系统(激光波长分为193 nm和213 nm两种),MPI Mainz实验室使用的就是这套系统,文章对此作一详细介绍。文中阐述了数据优化技术及其多种校正过程;介绍LA-ICPMS在痕量元素和同位素分析领域的一些应用,包括参考物质的研制,Hawaiian玄武岩、Martian陨石、生物骨针和珊瑚虫中痕量元素分析及熔融包裹体和富钙-铝碳质球粒陨石中的铅和锶同位素测量。     

NEITHER BIBLICAL PLAGUE NOR PRISTINE MYTH: A LESSON FROM CENTRAL EUROPEAN SPARROWS*

The historical superabundance of passenger pigeons in North America and of house sparrows in Central Europe is anthropogenic; that is, the result of human actions, in these cases with unintended consequences. In this article we concentrate on the superabundance of sparrows in the eighteenth and nineteenth centuries and outline the reasons for it. Both the passenger pigeon and the sparrow examples serve as ideal types for misplaced understanding of historical numbers of individuals as indicators of assumed pristine natural situations. Both examples reflect severe human impacts on the metapopulations of the bird species. Historical data on abundance can be misleading when they are used as guides in current conservation efforts. Selections of “right” numbers are arbitrary, because no points of reference exist in natural systems.     

Lateglacial varve chronology and biostratigraphy of lakes Holzmaar and Meerfelder Maar, Germany

In this paper we briefly compare previously published data on four lateglacial sediment profiles from lakes Holzmaar and Meerfelder Maar in the Eifel region. Two of these profiles (one from each lake) are varvedated, whereas the other two pollen profiles are on depth scales. In general, the palynological signal in all profiles compares well, proving the regional validity of the individual data sets. There are some discrepancies between Holzmaar and Meerfelder Maar, however, mainly concerning varve dating of major lateglacial features, and these are explained after detailed correlation using a combination of varve dating and palynological signals. The result is a consistent varve-dated biostratigraphy for the Lateglacial in the Eifel region. Moreover, it is demonstrated that a combination of varve chronology and high resolution palynostratigraphy in several lake profiles enables even gaps of a few decades up to a few centuries to be detected, thus providing a valuable tool for precise regional palaeoenvironmental study. This multi-core study on two lakes from the same region demonstrates the likelihood of undetected errors in single-core studies on non-varved sediments.     

Metasomatic Mantle Xenoliths from the Bismarck Microplate (Papua New Guinea)--Thermal Evolution, Geochemistry and Extent of Slab-induced Metasomatism

A suite of ultramafic mantle xenoliths from the TUBAF and EDISONseamounts in the Bismarck Archipelago NE of Papua New Guineawas sampled by video-guided grab. The xenoliths, which weretransported to the sea floor by rift-related, Quaternary trachybasalts,mainly represent part of the oceanic mantle. Mineral zoningin peridotite xenoliths testifies to slow cooling after mantleformation at a mid-ocean ridge. Cooling rates in the range of1°C/Ma were calculated from zoning of Ca in olivine usingthe Lasaga algorithm. Subsequent to this cooling, a strong metasomatismaffected the mantle peridotites when metasomatic agents emergedfrom the underlying slab of a subduction zone, which was stalledabout 15 my ago. This resulted in the formation of orthopyroxene-,clinopyroxene-, phlogopite- and hornblende-bearing veins crosscuttingspinel peridotites and olivine clinopyroxenites, as well aspervasively metasomatized plagioclase lherzolites. The metasomaticxenoliths reveal strong chemical disequilibria between the metasomaticminerals and the adjacent, unaltered host rock minerals, whichare especially prominent in the veined samples. Temperaturesduring the metasomatic overprint, estimated using spinel–olivinethermometry, range between 660 and 950°C. Oxygen barometryreveals an elevated oxygen fugacity, with