Helene Brätz's research while affiliated with Universitätsklinikum Erlangen and other places

Publications (52)

Article
Four isolated occurrences of Tertiary volcanic rocks in the northern Spessart at Beilstein, Hoher Berg, Madsteinand Kasselgrund are relics of volcanic vents or dikes. They display alkaline basalts (s.l.) with mainly trachybasalticcomposition, which, from normative mineral contents, may be designated as nepheline-bearing alkali-olivine basalts andba...
Article
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Imperial Porphyry, a famous dimension stone of spectacular purple color, was quarried in the Mons Porphyrites area north of Jabal Dokhan in the Eastern Desert of Egypt, from the beginning of the first until the middle of the fifth century AD. During this period, the valuable material was processed as decorative stone and was used for objects of art...
Article
The Münchberg Massif in northeastern Bavaria, Germany is an allochthonous metamorphic nappe complex within the Saxothuringian Zone of the Variscan orogen. From top to bottom it consists of four major units: Hangend-Serie, Liegend-Serie, Randamphibolit-Serie and Prasinit-Phyllit-Serie, which show an inverted metamorphic gradient of eclogite- to amph...
Article
Stratigraphically well-defined volcanic rocks in Palaeozoic volcano-sedimentary units of the Frankenwald area (Saxothuringian Zone, Variscan Orogen) were sampled for geochemical characterisation and U–Pb zircon dating. The oldest rock suite comprises quartz keratophyre, brecciated keratophyre, quartz keratophyre tuff and basalt, formed in Upper Cam...
Conference Paper
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Drill cores from the Lower Saxony Basin display iron and base metal sulfides in the Zechstein Staßfurt Carbonate (Ca2). The general geologic setting and geochemical conditions at which mineralizing events took place are currently being investigated within the framework of the BMBF-funded MinNoBeck project — 'Resource potential of covered hydrotherm...
Article
The distinction between regional metamorphic and metasomatic mineral assemblages may be occasionally challenging when the two phenomena show a very close spatial and temporal association. The Khetri complex in NW India, provides an excellent example of a geological terrane that has been significantly affected by metamorphism followed by extensive m...
Article
Cu- and Mn-bearing tourmalines from Brazil and Mozambique were characterised chemically (EMPA and LA-ICP-MS) and by X-ray single-crystal structure refinement. All these samples are rich in Al, Li and F (fluor-elbaite) and contain significant amounts of CuO (up to ~1.8 wt%) and MnO (up to ~3.5 wt%). Structurally investigated samples show a pronounce...
Article
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Copper-bearing tourmalines are highly prized for their vivid coloration. We analysed the major and trace elements of some gem-quality Cu-bearing tourmalines (e.g. blue, greenish blue, yellowish green, green, violet and pink) from Brazil, Mozambique and Nigeria. Most of them contained significant amounts of Cu, Mn or a combination of both elements....
Article
Electron microprobe and laser ablation-inductively coupled plasma mass spectrometric (LA-ICPMS) analyses were carried out on individual uraninite grains from several localities worldwide, representing a variety of different U-deposit types ranging in age from Mesoarchaean to the Mesozoic. For the first time, concentration data on a comprehensive se...
Article
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Ressourcen und Rohstoff e in der Bronzezeit Nutzung – Distribution – Kontrolle Beiträge zur Sitzung der Arbeitsgemeinschaft Bronzezeit auf der Jahrestagung des Mittel-und Ostdeutschen Verbandes für Altertumsforschung in Brandenburg an der Havel, 16. bis 17. April 2012 Brandenburgisches Landesamt für Denkmalpfl ege und Archäologisches Landesmuseum W...
Article
The distribution of mineral deposits, characterised as barite deposits, hematite-rich auriferous deposits and auriferous tourmaline–sulfide deposits, displays a regional sulfate–hematite–sulfide zoning along the thrust-delineated limbs of the Mariana anticline, in the south-eastern part of the Quadrilátero Ferrífero of Minas Gerais, Brazil. Cross-c...
Article
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Traces of water in mantle minerals strongly influence mantle melting and viscosity that, in turn, governs large-scale processes like mantle convection, plate tectonics, and the stabilization of cratons. One way of estimating the mantle's water content is by analyzing mantle xenoliths brought to the Earth's surface. A major problem in estimating the...
Article
Base-metal sulfides in magmatic Ni-Cu-PGE deposits are important carriers of platinum-group elements (PGE). The distribution and concentrations of PGE in pentlandite, pyrrhotite, chalcopyrite, and pyrite were determined in samples from the mineralized portion of four Merensky Reef intersections from the eastern and western Bushveld Complex. Electro...
Article
Enrichments in platinum-group elements were found in clausthalite, PbSe, which occurs in carbonate–hematite veins hosted in black shale of Upper Wenlockian age in the eastern Harz, Germany. Spot measurements by laser ablation–quadrupole inductively coupled plasma mass spectrometry (LA–QICPMS) show that the clausthalite has Pt contents that average...
Article
Cu- and Mn-bearing tourmalines from Brazil and Mozambique were characterised chemically (EMPA and LA-ICP-MS) and by X-ray single-crystal structure refinement. All these samples are rich in Al, Li and F (fluor-elbaite) and contain significant amounts of CuO (up to ~1.8 wt%) and MnO (up to ~3.5 wt%). Structurally investigated samples show a pronounce...
Article
Results of measurements on gypsum for gold (Au) and uranium (U) using laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) are reported. The Au contents were mostly below the average detection limit of 0.07 mu g/g, with a maximum value of 0.20 mu g/g Au, whereas the U concentrations vary from 0.04 to 1.82 mu g/g. The gypsum formed...
Article
Ferroselite from Trogtal, the type locality of the cobalt selenide trogtalite, in the Harz Mountains, Germany, forms a trogtalite-ferroselite assemblage in pockets of massive clausthalite in which specular hematite is dispersed. The pockets occur in hematite-impregnated carbonate veins, emplaced in a reddened greywacke of Lower Carboniferous age. F...
Article
Coltan (the African trade name for columbite-tantalite, a tantalum ore) is one of several raw materials that finance the civil wars in the eastern provinces of the Democratic Republic of the Congo. To improve the transparency along the tantalum trade chain, a ‘certificate of origin’ for so-called ‘conflict minerals’ has been recommended by the Unit...
Article
Tell Halaf is the locality of the ancient Aramaic city of Guzāna (c. 1000–800 bc) in Syria. The statues of Tell Halaf were made from monolithic basalt blocks, comprising massive as well as amygdaloidal types. However, the exact location of the original quarries was as yet unknown. Reconnaissance mapping and sampling concentrated on the four basalti...
Article
New data on rare earth element (REE) concentrations and distribution patterns of columbite-tantalite minerals from Ta-ore provinces worldwide are presented. The REE geochemistry was studied by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Five major types of chondrite-normalized REE distribution patterns are defined for c...
Article
A comparative in situ LA-ICP MS trace-element study on pyrite from three different, variably auriferous, Archaean to Palaeoproterozoic palaeoplacer deposits in the Ouro Fino Syncline (Quadrilátero Ferrífero; Brazil), the Elliot Lake area north of Lake Huron (SE Canada) and several deposits within the Witwatersrand Basin (South Africa) revealed syst...
Article
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Following the United Nations initiative to fingerprint the origin of conflict materials, the German Federal Ministry for Economic Cooperation and Development has decided to fund a pilot study on coltan ores. Since 2006, our working group has been investigating columbite-tantalite (coltan) mineralisation, especially in Africa, also within the wider...
Chapter
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The Léon domain adjacent to the Cadomian realm in the North Armorican domain appears to be a displaced crustal block, as its metamorphism and rock types bear a resemblance to the South Armorican domain of the internal Variscan belt. The amphibolite-facies Conquet-Penze Micaschist unit overlies the high-grade Lesneven Gneiss unit in the central part...
Article
Full-text available
[1] We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS....
Article
Full-text available
Zircon populations of Neoproterozoic and early Paleozoic age occur in metabasites of a high-pressure amphibolite-facies unit of the Austroalpine basement south of the Tauern Window. The host rocks for these zircons are eclogitic amphibolites of N-MORB-type character, hornblende gneisses with volcanic-arc basalt signature, and alkaline within-plate-...
Article
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The question, whether crustal domains are allochthonous terranes or not is crucial for plate tectonic models of the Ibero-Armorican segment of the Variscan belt. The Léon Domain in the Armorican Massif appears as a displaced crustal block as it bears a resemblance to the South Armorican Domain of the internal Variscan belt (Le Corre et al. 1989). I...
Article
The results of this pilot study show that using a commercial Merchantek 266 nm Nd:YAG laser system, laser ablation inductively coupled plasma - mass spectrometric analysis of fluid inclusions in quartz is possible. Fifteen elements (Li, Na, K, Mg, Fe, As, Rb, Sr, Sn, Ba, Mo, U, W, Mn, and Pb) were determined for aqueous fluid inclusions from the Zi...
Article
Full-text available
In the Austroalpine Basement to the south of the Tauern Window, distinct suites of metabasites occur with orthogneisses in pre-Early-Ordovician units. Tholeiitic and alkaline within-plate basalt-type metabasites are associated with acid meta-porphyroids in the post-Early-Ordovician Thurntaler Phyllite Group. According to their correlated trace elem...
Article
Results of TIMS, SIMS and SEM analyses show that zircon and monazite in a high-grade paragneiss of the Ruhla Crystalline Complex, central Germany, were formed and/or altered during different stages of a tectono-metamorphic history between Early Devonian and Permian times. Detrital zircon cores of >460Ma place an older limit on the age of anatexis,...
Article
The Ruhla Crystalline Complex (RCC) forms part of the NW trending Thuringian Forest horst block, which was affected by complex block faulting during Late Carboniferous/Early Permian times accompanied by an extensive magmatism. Block faulting results from dextral transtensive movements along the NW trending Franconian fault system, which separates t...
Article
The unique, coherent chemical properties of the rare earth elements (REE) make them highly suitable for geological studies into the history of rocks. Prior to the advent of reliable laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) methods, the steps required to prepare the rock samples for REE analysis were both time consumin...
Article
In this paper petrographical, geochemical and zircon morphological characteristics of granite gravels from different sediment beds of the northwestern Thuringian Forest are investigated. These are compared with granites from the Ruhla Crystalline Complex, assumed to be the gravel suppliers. The study shows that an assignment of gravels to granites...
Article
Ar/39Ar–mica and 207Pb/206Pb–zircon dates are presented and combined with existing P–T data and the sedimentary record. These data indicate that the RCC was faulted into three segments which underwent different exhumation histories during the Late Carboniferous/Early Permian. The eastern segment shows 40Ar/39Ar–biotite data of336 ±4 and 323±3 Ma. F...
Article
Detailed microprobe investigations were carried out on mineral phases of a mafic garnet-biotite-hornblende and garnet-biotite gneiss from the KTB main hole. The results indicate that the complex zonation patterns of garnet porphyroblasts are mainly due to post-growth diffusional exchange, as constrained by theoretical modelling. Moreover, the chemi...
Article
The metabasites from the KTB pilot and main drill holes can be divided into two major associations. The first is the metagabbro-amphibolite suite which is composed principally of metagabbros, basalts, and basaltic andesites with tholeiitic P-MORB affinities. The second is the amphibolite-gneiss suite that is characterized by alternating layers of m...

Citations

... This type of glass has been correspondingly designated as LMHK (low magnesium -high potassium) by Henderson (1988). Variants of this glass were further differentiated: glass with rather high K 2 O values (between 16% and 20%) in combination with a minute Na 2 O content was recognized as an independent glass type and designated as HKG (high-potassium glass) (Mildner et al., 2014(Mildner et al., , 2018Henderson, 2013). ...
... In the case of lithologies used as ornamental stone, they are valued for their aesthetics and their attractiveness and are generally used as a sign of distinction and just sometimes power, such as Roman porphyry (Abu El-Enen et al. 2018). The international interest in certain lithologies is well known, as is the case of Carrara marble (Primavori 2015) (Pereira and Cárdenes Van den Eynde 2019). ...
... Our new zircon U-Pb ages (ca. 530 Ma) show that the emplacement ages of S-type metagranite coincided with global Early Cambrian magmatism, which was generated during the Cadomian orogeny belt (e.g., Linnemann et al., 2000Linnemann et al., , 2008Nance et al., 2010;Yılmaz Ş ahin et al., 2014;Moghadam et al., 2015;Beyarslan et al., 2016;Koglin et al., 2018). ...
... The Lower and Middle Devonian sediments depict a continuation of the sedimentary style of the Silurian with the addition of minor psammitic intercalations. From the Lower Frasnian, bimodal within-plate magmatism Höhn et al. 2018) devel-oped intrusives exclusively within units of the Wrench-and-Thrust Zone (Fig. 5). Large volumes of tholeiitic magmatites are a characteristic feature of the Parautochthonous Unit. ...
... is still under debate and has been the subject of several recent research efforts, e.g., Will et al. (2016) and Wüstefeld et al. (2017), who focused their investigation on unravelling the thermal history and fluid evolution within the basin. Most recently, Sośnicka and Lüders (2018a) and Knorsch (2017) provided findings that class the sulfide mineralization in the LSB as the deep-seated expression of a potential Mississippi Valley-Type (MVT) deposit. Mempel (1962) was the first to note the different expressions of hydrothermal mineralization in the western and eastern part of the NGB, the LSB and the ABB, respectively. ...
... This type of glass has been correspondingly designated as LMHK (low magnesium -high potassium) by Henderson (1988). Variants of this glass were further differentiated: glass with rather high K 2 O values (between 16% and 20%) in combination with a minute Na 2 O content was recognized as an independent glass type and designated as HKG (high-potassium glass) (Mildner et al., 2014(Mildner et al., , 2018Henderson, 2013). ...
... There was no clear-cut correlation of the Cu and Mn contents with coloration. The blue color was in most cases due to Cu2+ (Okrusch et al, 2015). Pink and violet coloration (due to Mn3+) was shown by Mnbearing tourmalines that contained no significant Fe. Green color in the Nigerian tourmaline was most probably due to a combination of Mn, Cu, and Fe. ...
... Green may be caused by the combined action of Fe 2+ and Fe 3+ [5]. Blue is caused by Cu 2+ and Mn 3+ [2,6,7]. Scholars are also very interested in color causes of red tourmaline and have carried out a lot of research. ...
... This interpretation is consistent with the predominance of detrital zircon ages much older than the MAD, whereas ages close to MAD are quite rare and form a minor component . The extensional setting is also supported by sedimentary facies analysis of the North Delhi Supergroup rocks (Singh, 1988) and by geochemical data of quartzites (Kaur et al., 2016b). We note that the investigated conglomerates were also deposited in an extensional setting, most likely along a passive continental margin. ...
... In southern and western Europe, the magmatic pulse is compatible with subduction, delamination and/or slab break off (Boscaini et al., 2020;Gaggero et al., 2017;Pereira et al., 2014). Late Pennsylvanian to middle Permian rift basins show an extensive, but short-lived (305-270 Ma) magmatic pulse that accompanied extension (Ondrejka et al., 2018;Yuan et al., 2020;Zeh et al., 2000) that sometimes extended beyond the basin's margins (e.g., the Permian dyke and sill complexes of Northern England and Scotland; de Lamotte et al., 2015). In the case of the Neotethys rifting, plume volcanism was possibly involved. ...