Further Consideration of Two Photographs Ascribed to Christian Hornberger

Two reactions to the essay on the earliest generation of missionary photographers in West Africa published earlier in HA set up trains of thought which deserve to be minuted here as a further contribution to our praxis with images of Africa in the nineteenth century. It was pointed out by two readers of the original article that a pair of the images which, it had been asserted (104), derive from the last phase of Hornberger's photographic work, were published very early on in a non-mission context: that of three women spinning and that of one man weaving (figures 1 and 2 below). Both images exist as photographs, as stereographic vintage prints. Both were also published as wood engravings in mission periodicals (figures 3 and 4). Two readers of the original essay have pointed out that these images were conflated into a single engraving on page 211 of Richard Oberländer's Westafrika vom Senegal bis Benguela (Leipzig, 1874). In this image (figure 5), however, only two members of the group of spinning women are depicted, placed separately in the foreground, one on each side of the weaver. It is an ironic reflection on the quality of the documentation we have to fear in this field that Oberländer's caption—"Spinnende und webende Aschanti. (Nach einer Photographie)”—asserts specifically that the engraving was taken "from a photograph,” using the singular for

Photographie, Ethnographie und physische Anthropologie im 19. Jahrhundert: Ein Überblick für den deutschen Sprachraum

In the German-speaking world, attempts were made to document Man's bodily and cultural manifestations by means of photographs. Photography thus became a medium for making visual inventories, its impact being larger in physical anthropology than in ethnography. Of the steps taken to establish a morphological typology, that of Johann Goethe, a questionable conceptual systematization, prevailed over other empirically-based models. Late in the 19th century, the idea of a Photographic Museum of the Human Races lay behind the ever more frequent scientific application of photography to illustrations in compilations of a general character and to representations of whole ethnic groups. Technical innovations promoted initiatives aimed to overcome the static photography of the day.En el ámbito germano-parlante se intentó documentar las manifestaciones corporales y culturales del hombre a través de fotografías, como medio de inventario visual, incidiendo más en la antropología física que en la etnografía. Entre los diferentes intentos para la creación de una tipología morfológica, la cuestionable visión de Johann Goethe pasó a ser la sistematización conceptual dominante frente a otros modelos empíricamente fundados. El concepto de un museo fotográfico de las razas humanas constituyó la idea central para una aplicación científica de la fotografía. Su utilización se acrecentó a fines del siglo XIX, tanto en la ilustración de compilaciones de carácter global, como en representaciones de grupos étnicos completos. Las innovaciones técnicas fomentaron las iniciativas tendentes a superar la estática fotografía habitual

Significance of amphibole compositional zoning in para-amphibolite.

peer reviewe

PT-Daten aus niedriggradigen Metavulkaniten der Tiefbohrung Hasselfelde 1-83 (Mittelharz)

kein Abstract vorhande

Barrovian-type metamorphism in the western domain of the Cordillera Darwin Metamorphic Complex, Fuegian Andes

The Cordillera de Darwin Metamorphic Complex (CDMC) comprise metamorphosed supracrustal rocks and metaplutonic suites which records a unique tectonic evolution among the metamorphic complexes of the southernmost Andes. The pressure (P) and temperature (T) conditions determined in garnet-bearing schists in the Central Domain of the CDMC indicate a clockwise P-T path of metamorphism reaching burial depth as high as 12 kbar at ca. 620°C. This metamorphic event has been related to the closure of a marginal back-arc basin (Rocas Verdes Basin) and collision of an ensialic magmatic arc with the continent in the late Cretaceous. We focus on garnet-biotite schists intercalated within a huge block consisting of repeated sequences of metabasalts and amphibolites (Rocas Verdes Ophiolites), located in the Western Domain of the CDMC, at Seno Martínez. The chemical zonation of small garnet porphyroblasts (diameter of ca. 300 um) record two stages of metamorphism. Garnet is almost almandine in composition with lesser amounts of Ca, Mn and Mg. The concentric zonation is characterized by relatively lower contents of Fe-Mg and higher contents of Ca-Mn in the core. Garnet bear tiny inclusions of clinozoisite, which is also present as isolated grains in the foliated matrix. Laths of biotite define the main foliation and have a nearly constant composition characterized by XFe of ca. 0.6. Two generations of phengitic white mica are identified on basis of Si content (a.pf.u.) varying between 3.20-3.30 (early generation) and of ca. 3.15 (late generation). To reconstruct the P-T conditions of metamorphism through thermodynamic modeling using the Perple_X software package, the bulk rock and mineral composition were considered. Using compositional isopleths of XFe, XMg, XCa and XMn in zoned garnet, Si content in white mica and XFe in biotite allow the constrain two stages of metamorphism (M1 and M2). The P-T conditions of M1, represented by the composition of the garnet core, are restricted to ca. 8 kbar and 400°C. M2 is restricted to ca. 7.5 kbar at 480°C, determined with the composition of the garnet rim, XFe in biotite and Si content in late phengitic white mica. Our preliminary results indicate that ophiolitic rocks and interleaved garnet-bearing schists were tectonically buried and metamorphosed in a relatively hot subduction interface characterized by a geothermal gradient of ca. 16°C/km, prior to the collision of the ensialic magmatic arc.Fil: Calderón, Mauricio. Universidad Andrés Bello; ChileFil: Zuñiga, Catalina. Universidad Andrés Bello; ChileFil: Hervé, Francisco. Universidad Andrés Bello; Chile. Universidad de Santiago de Chile. Dto de Geología; ChileFil: Theye, Thomas. Staatliches Museum fur Naturkunde Stuttgart; AlemaniaFil: Galaz, Gonzalo. Universidad de Atacama.; ChileFil: Rojo, Diego. Universidad Arturo Prat; ChileFil: Suárez, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaEGU General Assembly 2021AlemaniaEuropean Geosciences Unio

Ashes of oxyfuel- and air-fired pulverised fuel combustion processes - mineralogical characterisation and long-term modification

The focus of our work was the mineralogical analysis of ashes obtained from the combustion of soft brown coal (93.4 % huminite, 4.2 % liptinite, 0.8 % inertinite, 1.6 % pyrite and quartz; detectable amounts of Ca, Fe, Na, K, Mg, Al, Si, S, Cl in the macerals) from the open mine site Welzow-Süd in Lower Lusatia (East Germany). The combustion process was achieved in the Atmospheric Pulverized Fuel Combustion Rig (KSVA) of the Institute of Combustion and Power Plant Technology (IFK), formerly Institute of Process Engineering and Power Plant Technology (IVD) at Universität Stuttgart in air and in the oxyfuel mode. Such ashes, which form during the combustion (oxyfuel process) for power production, were characterised with the methods of polarising microscopy, X-ray diffractometry, electron microprobe analysis and carbon/water-analytics and compared with ashes from the conventional combustion process in air

Actividad de fluidos hidrotermales del Neoproterozoico tardío en el cinturón de Tandilia, Argentina

In the Barker - Villa Cacique area, Tandilia belt, alteration mineral assemblages were studied by petrography, XRD and EMPA at three different stratigraphic levels: (1) a phyllic alteration at the unconformity palaeoproterozoic basement-neoproterozoic sedimentary succession (TLPU); (2) an advanced argillic alteration in the Las Águilas Formation (middle level); and (3) a phyllic alteration on pyroclastic rocks of the Olavarría Formation (upper level). Special emphasize was placed on the chemical characterization of K-white micas and chlorites. Secondary K-white micas of altered migmatites, from the Las Aguilas and Olavarría Formations have a low paragonite content (Na* 9.5 km) for the entire sedimentary pile. Hot fluids would rise from deep-seated realms, metamorphic and/or hidden igneous sources. A correlation with a rasiliano thermo-tectonic event is hypothesized.En el área de Barker - Villa Cacique, Tandilia, se estudiaron mediante petrografía, DRX, y microsonda electrónica, las para- génesis de minerales de alteración de tres niveles estratigráficos diferentes: (1) alteración fílica de la discordancia basamento paleoproterozoico-secuencia sedimentaria neoproterozoica (TLPU); (2) alteración argílica avanzada en la Formación Las Águilas (nivel medio); y (3) alteración fílica en rocas piroclásticas de la Formación Olavarría (nivel superior). Las micas potási- cas y cloritas, de dichos niveles de alteración, fueron caracterizadas químicamente. Las micas potásicas de migmatitas alteradas y de las formaciones Las Águilas y Olavarría tienen un bajo contenido en paragonita (Na* 9,5 km) para el total de la pila sedimentaria. Los fluidos hidrotermales habrían ascendido desde ambientes profundos con una fuente metamórfica y/o cuerpos ígneos ocultos. Una correlación con un evento termo-tectónico Brasiliano es hipotetizada.Fil: Martinez, Juan Cruz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Dristas, Jorge A.. Universidad Nacional del Sur. Departamento de Geologia. Catedra de Petrologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; ArgentinaFil: Van Den Kerkhof, Alfons M. . Geowissenschaftliches Zentrum der Universität Göttingen; AlemaniaFil: Wemmer, Klaus . Geowissenschaftliches Zentrum der Universität Göttingen; AlemaniaFil: Massonne, Hans J.. Universität Stuttgart; AlemaniaFil: Theye, Thomas. Universität Stuttgart; AlemaniaFil: Frisicale, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; Argentina. Universidad Nacional del Sur; Argentin

Confirmation of siderazot, Fe3N1.33, the only terrestrial nitride mineral

Siderazot, the only terrestrial nitride mineral, was reported only once in 1876 to occur as coating on volcanic rocks in a fumarolic environment from Mt. Etna and, to date, has been neither confirmed nor structurally characterized. We have studied the holotype sample from the Natural History Museum, London, UK, originally collected by O. Silvestri in 1874, and present siderazot with epsilon-Fe3N-type crystal structure and composition of Fe3N1.33(7) according to crystal structure Rietveld refinements, in good agreement with electron microprobe analyses. Crystal structure data, chemical composition, and Raman and reflectance measurements are reported. Possible formation conditions are derived from composition and phase stability data according to synthetic samples

Coeficientes de distribuição de elementos-traço em clinopiroxênio e plagioclásio de sills basálticos da Formação Serra Geral, Brasil

The use of an electron microprobe (EPMA) integrated with inductively coupled plasma mass spectrometer laser ablation (LA-ICP-MS) for the determination of major and trace elements in igneous minerals advances the knowledge of the distribution coefficients “D”in cores, intermediate portions and rims of crystals. Crystals of clinopyroxene and plagioclase of tholeiitic sills from the Serra Geral Formation, Paraná Basin, Brazil, display positive correlations between many major and trace elements. Plagioclase has core concentrations of SiO2 and Na2O wt.% which increase to the rim and Al2O3 and CaO wt.% decreasing from the core to the rim, corroborated by similar variations of distribution coefficients of Sr and Eu as a result of substitution of these compatible elements for Na in the structure of plagioclase. Clinopyroxene has the decreases in MgO, Al2O3 and CaO wt.% core to the rim and decreased D of Ni, Zn and V, and to increased concentration of FeOtotal wt.% core to the rim related increase in D of Sc, Y andHREE. This investigation is innovative because it presents the study of distribution coefficients oftrace elements with spatial control of the analyses, taking into account the effect of inclusions, fractures and compositional zoning.A utilização de técnicas de microanálise (microssonda eletrônica - EPMA e ablação a LASER em espectrômetro de massa com plasma indutivamente acoplado - LA-ICP-MS) de elementos maiores, traços e terras raras em minerais ígneos amplia o conhecimento do coeficiente de distribuição “D” em porções de núcleo, intermédio e borda do cristal. Cristais de clinopiroxênio e plagioclásio de sills toleíticos da Formação Serra Geral, Bacia do Paraná, Brasil, possuem correlações positivas entre muitos elementos maiores e traços. O plagioclásio possui em seu núcleo concentrações de SiO e Na O (peso %) 2 2 que aumentam para a borda e concentrações de Al O e CaO (peso %) que diminuem do núcleo para a 2 3 borda do cristal. Isto é corroborado pelas mesmas variações dos coeficientes de distribuição de Sr e Eu em decorrência de substituições destes elementos, nas posições estruturais do Na no plagioclásio. O clinopiroxênio mostra decréscimo nos conteúdos de MgO, Al O e CaO (peso %) do núcleo para a borda, 2 3 diminuição dos D de Ni, Zn e V e aumento das concentrações de FeO (peso %) do núcleo para a borda total relacionados com o aumento do D de Sc, Y e ETR pesados. Este trabalho é inovador, pois apresenta o estudo de coeficientes de distribuição de elementos traços com controle espacial das análises, controlando- se desta forma, a influência de inclusões, fraturas e zoneamentos composicionais