Description: The term " ontogeny ," which is commonly used in biology, was introduced into the Earth sciences in 1961 to include the genesis and evolution of single crystals and crystal aggregates. The term encompasses nucleation , growth , alteration , and destruction . We present results of studies concerning the ontogeny of natural corundum (rubies and sapphires), and the chemical and morphological evolution of corundum crystals from deposits in Africa (Kenya, Tanzania, Madagascar) and Southeast Asia (Vietnam). Trace-element compositions indicative for different corundum habits were determined by rim-to-rim LA-ICP-MS and electron microprobe analyses. Raman spectroscopy was applied for Cr 3+ photoluminescence mapping. Results traced the development of corundum crystals and the evolution of their chemistry and morphology, and helped to clarify the geological processes within particular deposits. These variations of corundum morphology are directly correlated with Cr and Fe contents and varying P-T conditions that prevailed during crystal growth. Dipyramidal habits combined with white color in corundum from two deposits in the Mangari area in Kenya have Cr concentrations of ~200–700 μg/g in crystals that grew under high P-T conditions. Prismatic habit of bright red ruby crystals was linked to Cr concentrations of ≥1500 μg/g in samples from Luc Yen (Vietnam) and Mangari (Kenya), formed under lower P-T . Concentrations of Cr between 700–1500 μg/g are associated with pink color and combinations of different habits (dipyramidal, prismatic, or dipyramidal-prismatic) in these samples. Contents of Fe ~700 μg/g and Cr ~1200 μg/g in sapphire crystals from the Morogoro area of Tanzania caused pink color that correlated with dipyramidal habit and elongation along the c axis. Rhombohedral habit and blue-violet color were observed at Cr ~600 μg/g and Fe ≥2000 μg/g in sapphires from Andranondambo in Madagascar, formed during the final stage of contact metamorphism.

Description: The Lengenbach (Switzerland) Pb-As-Tl-Zn deposit was formed from a sulfide melt at about 500 °C during Alpine metamorphism, but details on its formation and especially the source of the metals are still under debate. In this study we present two sample sets to address these questions: MC-ICP-MS analyses of thallium isotopes in sulfides, sulfosalts, and melt inclusions from the Alpine metamorphic Lengenbach deposit in the Binn Valley of Switzerland, the non-metamorphic Wiesloch Mississippi Valley-type deposit in Southern Germany, and the Cu- and As-rich mineralization at Pizzo Cervandone about 2 km SW of the Lengenbach deposit, which has been discussed as potential source of the Lengenbach metals. LA-ICP-MS analyses of micas from the Lengenbach deposit and surrounding country rocks between the deposit and the Pizzo Cervandone to trace potential metal-bearing fluid pathways. We found that Tl isotope compositions expressed as 205 Tl values in all investigated samples range from –4.1 ± 0.5 to +1.9 ± 0.5. The whole variation can be seen in the Lengenbach deposit alone, which hence records considerable fractionation even during high-temperature processes involving a sulfide melt. This large range of 205 Tl is thought to be caused by nuclear volume-dependent fractionation. Interestingly, the common fahlores at Lengenbach behave differently from all other investigated sulfosalts: based on their heavy isotopic composition together with a low As/S-ratio, they do not seem to be crystallized from the sulfide melt, but are interpreted to have formed from hydrothermal fluids enriched in the heavy Tl isotopes. Although As mobilization in the gneisses and dolomites surrounding the Lengenbach deposit is evident based on secondary arsenites, no traces of such a country rock fluid could be found in fissure micas at Lengenbach. Hence, considerations involving K/Rb, Rb/Tl, As/S, and Pb/Tl ratios in the sulfides and micas imply that the element enrichment in the Lengenbach deposit is either pre-Alpine or related to peak metamorphism, but occurred definitely before mica growth at Lengenbach.

Description: The Middle Miocene Afyon alkaline volcanic complex (western Anatolia) erupted lavas of highly variable geochemistry, ranging from silica-undersaturated to silica-oversaturated and from ultrapotassic to Na-alkaline compositions. There are two major volcanic groups showing substantial differences in K-enrichment and different Sr, Nd and Pb isotopic compositions: plagioclase–amphibole-bearing lavas and sanidine- and/or leucite-bearing lavas. The most remarkable feature of Afyon volcanism is the close relationship in time and space of these two lava types. There is clear stratigraphic evidence for a switch from early Si-oversaturated sanidine- and/or leucite-bearing lavas, towards Si-undersaturated sanidine- and/or leucite-bearing lavas, which eventually change to slightly Si-undersaturated to -saturated plagioclase–amphibole-bearing lavas that make up the youngest formations. This change in composition is coupled with a decrease in 87 Sr/ 86 Sr (whole-rock and in situ apatite, perovskite, melilite and clinopyroxene), 207 Pb/ 204 Pb, Zr/Nb and Th/Nb, and an increase in 143 Nd/ 144 Nd, 206 Pb/ 204 Pb, 208 Pb/ 204 Pb and Ce/Pb, thus delineating a systematic change from orogenic (crust-like) to anorogenic (within-plate) signatures. Magma genesis in the Afyon volcanic complex has been controlled by roll-back of a subducted lithospheric slab since the Early Tertiary and post-collisional extensional events in Miocene times. It is associated with the upwelling of asthenospheric mantle through a gap in the subducted slab under western Anatolia. Magmatism is concurrent with the collapse of the orogenic belt and the development of extension-related horst and graben structures. We interpret the geochemical transition from orogenic to anorogenic affinity as being due to the increasing role of lithosphere–asthenosphere interaction that is most strongly reflected in the geochemistry of the Afyon lavas. Melting of peridotite in the convecting mantle (asthenosphere) may be a viable model for the origin of the plagioclase–amphibole-bearing lavas. Their ubiquitous high K 2 O contents, orogenic trace element signatures and isotopic compositions imply that the asthenosphere-derived primary melts were contaminated by melts derived from lithospheric mantle containing an orogenic chemical signature. Conversely, the ultrapotassic sanidine- and/or leucite-bearing lavas are derived from at least two types of metasomatized lithospheric mantle. The dominant source is a phlogopite–pyroxene-rich metasome, which was generated by recycling of continental sediments during previous subduction episodes. This is responsible for the orogenic geochemical signature dominantly seen in lamproites and shoshonites. On the other hand, melting of recently generated phlogopite-wehrlite metasomes resulted in the parental melts of melilite-leucitites, which should be of proto-kamafugitic composition. The wehrlitic metasomes were generated when convecting mantle-derived precursor melts reacted with lithospheric mantle peridotite along the solidus ledge in the system lherzolite + CO 2 (〈22 kbar).

Description: Marine Isotope Stage 3 (MIS 3, 57–27 ka) was characterised by numerous rapid climate oscillations (i.e., Dansgaard-Oeschger (D/O-) events), which are reflected in various climate archives. So far, MIS 3 speleothem records from central Europe have mainly been restricted to caves located beneath temperate Alpine glaciers or close to the Atlantic Ocean. Thus, MIS 3 seemed to be too cold and dry to enable speleothem growth north of the Alps in central Europe. Here we present a new speleothem record from Bunker Cave, Germany, which shows two distinct growth phases from 52.0 (+0.8, −0.5) to 50.9 (+0.6, −1.3) ka and 47.3 (+1.0, −0.6) to 42.8 (±0.9) ka, rejecting this hypothesis. These two growth phases potentially correspond to the two warmest and most humid phases in central Europe during MIS 3, which is confirmed by pollen data from the nearby Eifel. The hiatus separating the two phases is associated with Heinrich stadial 5 (HS 5), although the growth stop precedes the onset of HS 5. The first growth phase is characterised by a fast growth rate, and Mg concentrations and Sr isotope data suggest high infiltration and the presence of soil cover above the cave. The second growth phase was characterised by drier, but still favourable conditions for speleothem growth. During this phase, the δ13C values show a significant decrease associated with D/O-event 12. The timing of this shift is in agreement with other MIS 3 speleothem data from Europe and Greenland ice core data.

Description: This paper contains the results of an extensive isotopic study of United States Geological Survey GSD-1G and MPI-DING reference glasses. Thirteen different laboratories were involved using high-precision bulk (TIMS, MC-ICP-MS) and microanalytical (LA-MC-ICP-MS, LA-ICP-MS) techniques. Detailed studies were performed to demonstrate the large-scale and small-scale homogeneity of the reference glasses. Together with previously published isotopic data from ten other laboratories, preliminary reference and information values as well as their uncertainties at the 95% confidence level were determined for H, O, Li, B, Si, Ca, Sr, Nd, Hf, Pb, Th and U isotopes using the recommendations of the International Association of Geoanalysts for certification of reference materials. Our results indicate that GSD-1G and the MPI-DING glasses are suitable reference materials for microanalytical and bulk analytical purposes.

Description: This collection of articles represents the fourth in a series of reviews in which authors have aimed at capturing the key advances in a range of analytical fields (Hergt et al. 2005, 2006, 2008). The publication period under review is 2008–2009 and the intention here is to provide readers with a summary of the most influential developments published during this period, across a broad range of topics appropriate to the Earth and environmental sciences. Most authors comment on the ways in which the emphases of research in their specific fields of examination have changed over time. All note an increase in rigour and focus on data quality. Whether advances have taken place in instrumentation, sample manipulation or data deconvolution, there are a large number of dedicated scientists out there contributing to the high quality of geochemical data employed in geological and environmental research.

Description: The origin of Italian kamafugites and lamproites is a matter of debate, not least due to their “crustal signature” displayed by trace element compositions and isotopic ratios, but also due to puzzling geodynamic significance. We combine in situ EMPA and LA-ICP-MS analyses with in situ analyses of oxygen isotopes (SIMS) on olivine from the Pleistocene San Venanzo kamafugites and Torre Alfina lamproites. Lamproitic olivine shows extremely high Mg# and Ni concentrations whereas Ca and Mn concentrations are low. Their δ18OV-SMOW values are very high up to +11.5 ‰. In kamafugites we recognize three genetically different olivine groups: (a) phenocrystic one with high Mg#, very low Ni, high Ca and Mn. Values of δ18OV-SMOW are up to +10.9 ‰; (b) melt-related xenocrystic grains that compositionally resemble lamproitic olivine; (c) skarn-related almost pure forsterite of extreme δ18OV-SMOW ∼27 ‰, with negligible amounts of minor and trace elements. The melting and crystallization conditions of Italian kamafugites and lamproites indicate compositionally heterogeneous mantle sources on very small scales. Distinct geochemical features of the olivine macrocryst populations observed in kamafugite point to a range of processes occurring both within the magma storage and transport system. We suggest that the diversity of metasomatic agents was involved in mantle processes on local scales, coupled with magma mixing and/or the uptake of xenocrysts during magma ascend