Rainer Altherr

Universität Heidelberg · Institute of Earth Sciences

In the Republic of North Macedonia, the northern marginal part of the Pelagonian Unit comprises several isolated slivers of low-grade blueschist-facies rocks. These rocks were metamorphosed at conditions of the epidote-blueschist facies with rare transitions to the lawsonite-epidote blueschist facies. If present, lawsonite occurs as relic inclusion...

This study deals with the age and petrogenesis of mafic-ultramafic intrusions ranging in size from a few meters to 10 km within the Early Carboniferous high-grade gneisses of the Pulur Complex in the Eastern Pontides. The intrusions comprise dunite, wehrlite, gabbronorite, leucogabbro, anorthosite and ilmenite-bearing gabbronorite of cumulus origin...

Like the Moldanubian parts of the Bohemian Massif and the French Massif Central, the Vosges Mts (NE France) comprise an uppermost tectonic unit that consists of retrograded (U)HP/UHT granulites, eclogites and garnet peridotites, originally metamorphosed at pressures of ≥ 4 GPa and temperatures of ≥ 950 °C. Two amphibole–garnet–spinel-bearing perido...

We investigated the ⁵³Mn-⁵³Cr isotopic composition of a suite of enstatite chondrites by in situ analyses of various mineral phases with the Cameca IMS 1280-HR ion probe at Heidelberg, Germany, and a Cameca NanoSIMS at Paris, France. Only in sphalerite we found anomalies in ⁵³Cr/⁵²Cr-ratios correlating with ⁵⁵Mn/⁵²Cr which are due to decay of short...

In the Variscan Schwarzwald metabasic rocks form small bodies included within anatectic plagioclase-biotite gneisses. Many metabasites first underwent an eclogite-facies metamorphism at about 2.0 GPa and 670–700 °C, resulting in the assemblage garnet + omphacite + rutile + quartz ± epidote ± amphibole ± kyanite. Since these eclogites are nearly fre...

The Variscan Rand Granite as defined in this paper is a deformed I-type biotite granite that intruded along the southern-to-southeastern margin of the Central Schwarzwald Gneiss Complex. Former K-feldspar megacrysts (now porphyroclasts) of this K–Mg-rich alkali-calcic granite frequently show zonal crystallographic arrangement of mineral inclusions...

The volcanic field of Harrat ar Rahah-’Uwayrid (NW Saudi Arabia) consists of an older plateau basalt sequence that overlies Cambrian sandstone and younger cinder cones with smaller flows that are concentrated in the central part of this field. Petrographic and whole rock geochemical data indicate that the older plateau basalts are alkali olivine ba...

High-grade metamorphic soles in NE Bosnia and Herzegovina make part of the Krivaja-Konjuh ophiolite complex (KKOC), which is one of the most important constituents of the Jurassic ophiolite mélange of the Central Dinarides. Several rock types were distinguished within the investigated metamorphic suite - sapphirine and corundum amphibolites, garnet...

In the Variscan Vosges Mountains (France) small bodies of orogenic garnet peridotite occur within felsic gneisses (former granulites). In most of these peridotite bodies the original garnet is completely transformed to kelyphite surrounded by a relatively thin two-layer corona of orthopyroxene 6 clinopyroxene and orthopyroxene + clinopyroxene + spi...

The Eastern Mediterranean region within the Tethyan belt is characterised by two main pulses of suprasubduction-zone ophiolite formation during the Early-Middle Jurassic and Late Cretaceous. Despite vast exposures of the Permo-Triassic accretionary complexes, related suprasubduction-zone ophiolites and the timing of subduction initiation leading to...

Trace element compositions of clinopyroxene and oxidation state measurements are both useful parameters for constraining metasomatic interactions within the subcontinental lithospheric mantle (SCLM). Laser ablation inductively coupled plasma mass spectrometry analyses of trace elements in clinopyroxene in combination with oxidation state data from...

We present the first comprehensive noble gas study on eclogites. The four eclogite samples were recovered during the Chinese Continental Scientific Drilling and are from two distinct profile depth sections differing in their degree of interaction with meteoric water, based on their δ18O-values (surface related and of mantle-type). Hence, noble gas...

In this paper we present the results of the analysis of lithic industry from Vlakno Cave, which was discovered during excavations in 2004 and 2007. Radiocarbon dating positions the analysed lithic industry at the time of Pleistocene-Holocene transition. The technological and typological features of the lithic production show continuity during the a...

Within the Tethyan realm, data for the subduction history of the Permo-Triassic Tethys in form of accretionary complexes are scarce, coming mainly from northwest Turkey and Tibet. Herein we present field geological, petrological and geochronological data on a Triassic accretionary complex, the Ağvanis metamorphic rocks, from northeast Turkey. The A...

A new occurrence of Mn-rich rocks was discovered within the high-pressure/low-temperature metamorphic rocks on the Palos peninsula of Syros (Greece). Near the summit of Mount Príonas, a meta-conglomerate consists of calcite (~63 wt%), pink manganian phengite, blue–purple manganian aegirine–jadeite, microcline, albite and quartz. In addition, it con...

NanoSIMS analyses of three different sphalerite grains of EH3 Sahara 97158 yield ^53Cr excess up to 3500 ‰. A precise isochron defines an initial ^53Mn/^55Mn ratio of (3.14 ± 0.26) x 10^–6, corresponding to an absolute age of 4562.7 ± 0.5 Ma.

Li, Be, B and δ7Li SIMS analyses of plagioclase phenocrysts from the 1040–1941 Niki dacite lava (Nea Kameni, Santorini, Greece) exhibit varied processes. From their anorthite contents alone, the crystals may be segregated into four main types: type-N shows the normal decline in An during crystallisation (An62–40); type-O has only oscillatory zoning...

Investigating regional variations in structure and composition of the subcontinental lithospheric mantle (SCLM) is usually hampered by the lack of samples. However, the numerous volcanic centers of the French Massif Central have brought samples of the SCLM to the surface over a geographic area of ~20.000km2. Lenoir et al. (2000) and Downes et al. (...

The return of Early Cycladic objects from the collection of the Badisches Landesmuseum of Karlsruhe resulted from the acknowledgment that the museum's problematic former acquisitions policy needed to be revisited. But voluntary restitution can be only one element of a constructive solution for dealing with antiquities of unknown provenance acquired...

The Tertiary and Quaternary volcanism of the French Massif Central sampled the underlying subcontinental lithospheric mantle (SCLM) in the form of xenoliths over a wide geographic area of ~20.000km2. Such an extensive distribution of xenoliths provides an unique opportunity to investigate regional variations in mantle structure and composition. On...

Concentrations of boron in whole rocks and minerals of the peralkaline, 1.16 Ga Ilímaussaq intrusion and its granitic country rocks (South Greenland) were analysed using secondary ion mass spectrometry (SIMS) and prompt gamma neutron activation (PGNAA) analysis. The intrusion consists of an early augite–syenite shell, a later alkali-granite sheet a...

In the Anatolia, the Caucasus and northwest Iran, the Eocene epoch is characterized by widespread basic to acidic magmatism, whose temporal and spatial evolutions and origin are poorly understood. In this paper, we provide geochronological and geochemical data on a suite of Early Eocene intrusions from northeast Turkey and discuss their origin with...

To investigate the geochemical behaviour of argon isotopes during mantle metasomatism and to obtain chronological information on the age of metasomatic events under the Arabian Shield, we analyzed mantle xenoliths and hornblende megacrysts from Saudi Arabian volcanic fields (Uwayrid, Al Birk) applying the 40Ar-39Ar dating technique. Two hornblende...

Two rare amphibolite parageneses consisting of Am, Pl, Spr, and Spl (paragenesis 1), and Am, Pl, Crn, and Spl (paragenesis 2) were reported within the suite of metamorphic sole rocks that are associated to the Krivaja-Konjuh ophiolite complex (KKOC) in NE Bosnia and Herzegovina. It is the biggest Tethyan ophiolite complex of the CDOB, hosting diver...

Sediment-filled karst depressions (e.g. dolines) have rarely been used as geoarchives in Greece due to an uncertainty about the thickness of accumulations and their vague suitability for palaeoenvironmental research. However, such terrestrial proxy-data sources can yield important records for the analysis of the Holocene landscape history. A multi-...

Keywords: High-K granite Sr–Nd isotopy Ar–Ar dating U–Pb zircon dating Variscan orogeny Eastern Pontides Turkey The Gümüşhane pluton, a high-K calc-alkaline I-type granodiorite/granite complex, forms an important component of the pre-Liassic basement of the Eastern Pontides (NE Turkey). In its eastern part, the pluton shows a compositional zonation...

Shock veins up to 1.1mm thick were found within non-porous lithic clasts from suevite breccia of the Nördlinger Ries impact structure. These veins were studied by optical microscopy in transmitted and reflected light and by scanning electron microscopy. In shocked amphibolites, two types of Ca-rich majorite occur within and adjacent to the veins. T...

An eclogite barometer has profound importance in the study of upper mantle processes and potential application to diamond prospecting. Studies on the partitioning of Li between clinopyroxene (cpx) and garnet (grt) in natural samples have shown that this particular element is very sensitive to changes in pressure and could be calibrated as the barom...

The investigation of sediments, soils and minerals can provide important information for the reconstruction of past landscapes and the human impact on the environment. In this context, sediment-filled karst depressions function as archives as their different sediment structures reflect various superficial conditions and associated man-made changes...

Focusing on the currently uninhabited plateau of Zominthos at 1200 m a.s.l. in Central Crete, which - according to huge archaeological remains - was densely populated during the Minoan era (Neopalatial period, ca. 1650 B.C.), the main objective of the project is to reconstruct the Bronze-Age landscape evolution with special regard to human-environm...

Garnet-bearing and garnet-free pyroxenite xenoliths from Quaternary basanites of Marsabit, northern Kenya, were analysed for microstructures and mineral compositions (major and trace elements) to constrain the thermal and compositional evolution of the lithospheric mantle in this region. Garnet-bearing rocks are amphibole-bearing websterite with ~5...

High-pressure metamorphic (HPM) rocks (derived from igneous protoliths) and their metasomatised rinds from the island of Syros (Greece) were analysed for their B and Cl whole-rock abundances and their H(2)O content by prompt-gamma neutron-activation analysis (PGNAA) and for their Li and Be whole-rock abundances by ICP-OES. In the HPM rocks, B/Be an...

Concentrations of Li, Be and B and the isotopic composition of lithium have been measured in minerals from a suite of dry and metasomatised spinel peridotite and pyroxenite xenoliths from Harrat Uwayrid, a Pliocene–Quaternary volcanic field in the NW part of the Arabian peninsula, developed during formation of the Red Sea. In most peridotites, Li c...

A blueschist facies tectonic sliver, 9 km long and 1 km wide, crops out within the Miocene clastic rocks bounded by the strands of the North Anatolian Fault zone in southern Thrace, NW Turkey. Two types of blueschist facies rock assemblages occur in the sliver: (i) A serpentinite body with numerous dykes of incipient blueschist facies metadiabase (...

In the southern zone of the Eastern Pontides, an isolated small (~ 1.5 km2) outcrop of plagioleucitites occurs in the Aşutka thrust sheet. Field relations constrain the timing of volcanism between Maastrichtian and late Paleocene. The plagioleucitites consist of clinopyroxene, analcime (former leucite), Ti-magnetite, plagioclase, sanidine, apatite...

Two large pegmatitic crystals of sodic pyroxene (aegirine) and sodic amphibole (arfvedsonite) from the agpaitic igneous Ilímaussaq Complex, south Greenland were found to be suitable as reference materials for in situ Li isotope determinations. Lithium concentrations determined by SIMS and micro-drilled material analysed by MC-ICP-MS generally agree...

The boron isotopic composition of zoned tourmaline in two metasediments from the island of Syros, determined by secondary-ion mass spectrometry (SIMS), reflects the sedimentary and metamorphic record of the rocks. Tourmaline from a silicate-bearing marble contains small (≤20 μm) detrital cores with highly variable δ 11B values (−10.7 to +3.6‰), poi...

Ultramafic cumulates of Medvednica Mts form mega-blocks in the ophiolite mélange from the Zagorje-Mid-Transdanubian segment of the Sava Zone. The blocks consist of chromite-olivine cumulates and pyroxenites. The rocks crystallized in an open system under low pressure. Early crystallization of Al-Ti-chromite and Ti-edenite/pargasite indicate high ox...

Harrat Uwayrid is one of several volcanic fields that developed along the western margin of the Arabian plate during opening of the Red Sea rift. Volcanic activity started in the late Miocene and Pliocene with the eruption of alkaline flood basalts. After a period of extensional faulting, numerous cinder cones formed in the central part of the volc...

The Kurtoğlu metamorphic complex, that forms part of the pre-Liassic basement of the Sakarya zone in northern Turkey, consists of at least two tectonic units. Blueschist-facies rocks of unknown metamorphic age in the southern part of the complex are tectonically overlain by Variscan low-pressure high-temperature metamorphic rocks. The latter compri...

We performed a noble gas isotope study on mantle xenoliths from the Quaternary volcanic field of Chyulu Hills, S Kenya, c. 100 km east of the Kenya rift graben. 4He/3He ratios were in the range of 100 000–120 000 and indistinguishable from other subcontinental lithospheric mantle compositions worldwide and similar to most results of the East Africa...

We performed argon measurements on rocks of the subcontinental lithospheric mantle (SCLM) from the Red Sea region applying stepwise crushing extractions, and argon analyses using high-resolution stepwise heating techniques, the latter combined with 40Ar/39Ar dating. Maximum 40Ar/36Ar ratios of individual samples range from 4190 ± 240 to 25,590 ± 62...

The microtextures of stishovite and coesite in shocked non-porous lithic clasts from suevite of the Ries impact structure were studied in transmitted light and under the scanning electron microscope. Both high-pressure silica phases were identified in situ by laser-Raman spectroscopy. They formed from silica melt as well as by solid-state transform...

A model for the release of Li, Be and B from progressively dehydrating altered oceanic crust during subduction is presented. Combining clinopyroxene/fluid partition coefficients determined experimentally in an earlier study Brenan et al. [Brenan, J.M., Ryerson, F.J., Shaw, H.F., 1998. The role of aqueous fluids in the slab-to-mantle transfer of bor...

Neogene to Quaternary mafic alkaline volcanism in the Eifel is part of the Central European volcanic province. Timing and geographical distribution suggest a common, plate-scale origin, either by passive or active mantle upwelling. Seismic tomography suggests confined, narrow plume-structures in the upper mantle below the Eifel and the Massif Centr...

The Lower Cretaceous (123-115 Ma) low-grade metamorphic complex of the Medvednica Mts. is located within the southwestern edge of the Mid-Trans- Danubian shear zone. The SW-NE striking complex consists of metabasites overlain by metasediments, both affected by a single metamorphic event. Metamorphic parageneses and mineral compositions of the metab...

High-pressure (HP) metamorphic blocks enclosed in a mafic to ultramafic matrix from a mélange on the island of Syros are rimmed by tourmaline-bearing reaction zones (blackwalls). The B isotopic composition of dravitic tourmaline within these blackwalls was investigated in situ by secondary ion mass spectrometry. Boron in these tourmalines is unusua...

Pelagic micritic limestones within an upper Cretaceous accretionary complex in the Tavşanlı Zone, NW Turkey, preserve textures indicating incomplete prograde transformation of micritic calcite to aragonite, representing the only known example of this type. Aragonitization starts at the central parts of the micritic limestone beds and advances towar...

Partitioning and budget of Li, Be and B in high-pressure metamorphic rocks from the island of Syros (Greece) were studied, using secondary ion mass spectrometry, inductively coupled plasma optical emission spectrometry and prompt gamma neutron activation analysis. Partitioning between coexisting mineral phases was found to be rather constant and in...

Plio-Pleistocene volcanism in the Golan and Galilee (northeastern Israel) shows systematic variability with time and location: alkali basalts were erupted in the south during the Early Pliocene, whereas enriched basanitic lavas erupted in the north during the Late Pliocene (Galilee) and Pleistocene (Golan). The basalts show positive cor- relations...

Nea Kameni is the larger of two intra-caldera islands in Santorini Volcano, the most active volcanic center of the Hellenic Arc in Greece. Phenocrysts of samples collected from the 1939-1941 dacite lava flows were analyzed for major and trace element compositions using the EMP and SIMS, with particular focus on concentrations of Li, Be and B. Three...

The post-collisional Saraycık granodiorite intruded into a late Paleocene to early Eocene nappe pile that formed during collision of the Pontides in the North and the Anatolide-Tauride platform in the South, leading to the formation of the İzmir-Ankara-Erzincan suture. A relatively shallow pluton intrusion depth (∼5 to 8km) was estimated from Al-in...

Solar-type helium (He) and neon (Ne) in the Earths mantle were suggested to be the result of solar-wind loaded extraterrestrial dust that accumulated in deep-sea sediments and was subducted into the Earths mantle. To obtain additional constraints on this hypothesis, we analysed He, Ne and argon (Ar) in high pressure–low temperature metamorphic rock...

High-pressure metamorphic rocks showing a large range of chemical compositions were analyzed by PGNAA, XRF and solution ICP-MS for major components and a variety of trace elements. The large data set allowed a comparison of results from PGNAA to the established methods and revealed good agreement for most major elements and for Sc and Gd. For V, Cr...

Noble gas isotopes are widely used to elucidate the history of the rocks in which they have been trapped, either from distinct reservoirs or by accumulation following radioactive decay. To extract noble gases from their host rocks, stepwise heating is the most commonly used technique to deconvolve isotopically different components, e.g., atmospheri...

Late Cenozoic mafic alkaline volcanism associated with lithospheric thinning is a widespread phenomenon in Europe. However, there is no consensus about its geodynamical causes, e.g., if active shallow or deep mantle-derived plume upwelling has driven this activity. Seismic tomography demonstrated 400–500 km deep plume-like structures under the Mass...

Solar-type helium (He) and neon (Ne) in the Earth's mantle were suggested to be the result of solarwind loaded extraterrestrial dust that accumulated in deep-sea sediments and was subducted into the Earth's mantle. To obtain additional constraints on this hypothesis, we analysed He, Ne and argon (Ar) in high pressure-low temperature metamorphic roc...

An undated high-pressure low-temperature tectonic mélange in the Elekdağ area (central Pontides, N Turkey) comprises blocks of MORB-derived lawsonite eclogite within a sheared serpentinite matrix. In their outer shells, some of the eclogite blocks contain large (up to 6 cm) tourmaline crystals. ‘Prograde’ inclusions in poikiloblastic garnet from a...

A dense (~3.34gcm–3) garnet–sillimanite-rich metamorphic rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as...

High-grade gneisses from the Pulur complex in NE Turkey bear evidence for biotite-dehydration melting at 820C and 0.7–0.8GPa, melt segregation and near-isothermal decompression to 0.4–0.5GPa. During further exhumation, the rocks underwent secondary pervasive rehydration at temperatures between 400 and 230C and fluid pressures between 0.3 and 0.1GPa...

In the Pulur complex, NE Turkey, a heterogeneous rock sequence ranging from quartz-rich mesocratic gneisses to silica- and alkali-deficient, Fe-, Mg- and Al-rich melanocratic rocks is characterized by granulite-facies assemblages involving garnet, cordierite, sillimanite, ilmenite, ±spinel, ±plagioclase, ±quartz, ±biotite, ±corundum, rutile and mon...

Helium and neon isotopes are ideal tracers to quantify contributions of primitive mantle plumes, which are characterized by a higher proportion of primordial solar-type noble gases compared to lithospheric or asthenospheric mantle sources. This property was used to investigate the role of the Afar mantle plume (a high 3He/4He plume of up to 20 RA;...

The abundances of lithium, beryllium and boron in mineral grains from the ultrahigh-pressure garnet peridotite of Alpe Arami were studied by secondary ion mass spectrometry. In order to eliminate the ubiquitous B contamination problem, polished thin sections were cleaned twice in an ultrasonic cleaner using ultrapure water from a Milli-Q water puri...

In the Pulur complex (Sakarya Zone, Eastern Pontides, Turkey) a low-grade tectonometamorphic unit (Doankavak) is exposed in three tectonic windows beneath a complex medium-pressure high-temperature metamorphic unit of late Carboniferous age. The thrust plane between both units is transgressively covered by Liassic conglomerates. The Doankavak unit...

In the East European Alpine belt, leucite-sanidine-phlogopite-olivine-bearing volcanic rocks of Late Cenozoic age occur at eight localities within the Vardar suture zone and at one locality in the Southern Carpathian fold-and-thrust belt. Most of these volcanics are characterized by high Mg# (66.6–78.6), high abundances of Ni (117–373ppm) and Cr (1...

The Pb isotope compositions of amphiboles and clinopyroxenes in spinel peridotite and pyroxenite mantle xenoliths from the intra-plate Quaternary volcanic fields of the Eifel province (Germany) are strongly correlated with their Sr–Nd isotope and trace element compositions. High-temperature anhydrous xenoliths from a depth of around 60 km have trac...

Previous studies suggest that the metamorphic evolution of the ultrahigh-pressure garnet peridotite from Alpe Arami was characterized by rapid subduction to a depth of c. 180 km with partial chemical equilibration at c. 5.9 Gpa/1180 °C and an initial stage of near-isothermal decompression followed by enhanced cooling. In this study, average cooling...

The Harrat Uwayrid is a Late Miocene to Quaternary volcanic field located in the northwestern part of the Arabian plate and related to the opening of the Red Sea. Numerous cinder cones contain abundant mantle xenoliths. Based on mineralogy and textures, these xenoliths can be subdivided into 3 different groups. Group IA1 are "anhydrous" spinel lher...

On Lesbos Island, Miocene volcanics overlie a metamorphic basement of late Palaeozoic to early Mesozoic age (e.g. [1]). The 17.0 ±0.5 Ma old [2] ignimbritic unit of Lesbos is over 100 m thick and covers approximately 190 km^2. Two vertical profiles through the ignimbrite were mapped and sampled. The deposit is extremely welded and dense. Relative a...

The Heidelberg Cameca ims-3f ion probe has been modified in order to measure delta11B values with a precision of ±1 ppm (2sigma) in tourmaline, ±2 ppm in phengite (≈100 mug/g B), and ±4 ppm in other minerals (2--10 mug/g B). Three tourmaline standards (98144 elbaite, 112566 schorl and 108796 dravite; [1]) of different chemical compositions were...

The mineral phases of 33 eclogite and garnet clinopyroxenite samples from various tectonic settings were analysed for Li by secondary ion mass spectrometry (SIMS). In all samples, Li is preferentially incorporated into clinopyroxene (0.4 to 80 g/g), whereas co-existing garnet contains only minor amounts of Li (0.01 to 3.7 g/g). When present, glauco...

The inter- and intragrain distribution of Li and Be in the subduction-related ultrahigh-pressure (UHP) garnet peridotite from Alpe Arami, Central Swiss Alps, was studied using secondary ion mass spectrometry. The data indicate substantial Li infiltration during exhumation of this ultramafic body. Orthopyroxene porphyroclasts and neoblasts are chara...

Miocene extension in the Aegean Sea was accompanied by the intrusion of granitoid and monzonitic magmas at upper crustal levels. With increasing distance from the trench, the metaluminous to slightly peraluminous I-type intrusives show a systematic regional variation in their compositions: medium- to high-K granodiorites in the WSW, high-K low-sili...

The lattice strain model, in which crystal-melt partitioning of trace elements has a parabolic dependence on ionic radius is now generally accepted as describing the behaviour of many elements entering liquidus silicates. Given that we can, for ions of a fixed charge, characterise partitioning in terms of the 3 parameters, E (Youngs Modulus of the...

The metamorphic evolution of the garnet peridotite body of Alpe Arami, Central Alps, is a matter of current controversy. In this paper, the inter- and intragrain distribution of major and trace elements obtained by electron and ion probe microanalyses is used to better constrain the P-T evolution of this peridotite. Using the compositions of homoge...

A series of recently and previously collected peridotite xenolith samples from the western Pannonian Basin has intensively been studied using electron microprobe techniques and a thermo-barometric approach in order to obtain relevant information about the thermal evolution of the lithosphere. Most of the xenoliths have chemically homogeneous minera...

Early Carboniferous high-K, calc-alkaline I-type plutonic rocks from the northern Vosges and Schwarzwald were studied for their chemical and Sr–Nd isotopic compositions. Intrusion relationships and mineralogical and chemical characteristics allow to distinguish four suites. The oldest intrusions are diorites (1), followed by a granodioritic (2) and...