Other language confidence: 0.9034746060727483
The Valles Caldera, New Mexico, USA was created by two caldera-forming eruptions at ~1.6 and ~1.1 Myr. Since then, post-caldera activity has consisted of lava domes, lava flows, large explosive phases, and a hydrothermal system active today. Possibly the youngest eruption sequence, El Cajete, was emplaced 74.4 ± 1.3 ka (Zimmerer et al., 2016) and began with pyroclastic surges, followed by pyroclastic density currents (PDCs) and pumice-rich Plinian pyroclastic fall (Self et al., 1988). The objective of this project was to characterize crystal grains from the early El Cajete sequence, in terms of morphology and textures, using scanning electron microscopy (SEM). The early El Cajete differs from the later part of the sequence in its greater stratigraphic and lithologic complexity, having been formed from not only pyroclastic fall (like the later El Cajete) but also surge beds and PDCs. This dataset was collected under the national open access action at Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa SEM/EDS facility supported by WP3 ILGE – MEET project, PNRR – EU Next Generation Europe program, MUR grant number D53C22001400005. This allowed me to obtain the present dataset of 31 cathodoluminescence (CL) images of 30 quartz crystals and one sanidine crystal.
Other
This publication provides mineralogical and geochemical data of two 6-m-deep weathering profiles formed from granitic rock. They are located in different climate zones (Mediterranean and humid) and are close to the national parks of La Campana and Nahuelbuta in the Chilean Coastal Cordillera. Additional rock samples from adjacent boreholes were used to relate the regolith to the bedrock. The profiles were sampled in February and March 2020 as part of the German Science Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota”. The goal of this project is to obtain a holistic view on the interplay of the geosphere and the biosphere under different climatic conditions and to investigate weathering mechanisms. The aim of this publication is to provide the data basis for understanding the weathering processes that control the development of the profiles in relation to different climatic conditions. To this end, we measured the geochemistry with X-ray fluorescence, extracted Fe, Al and Si with oxalate/dithionite, determined the grain sizes by wet sieving and pipetting, measured the magnetic susceptibility, and analysed the mineral content of bulk samples and clay fractions with X-ray diffraction. The data are compiled in one Excel file and all results of the X-ray diffraction measurements are available as RAW- and TXT files.
This data set is Part 2 of the compiles whole-rock chemical data for late-Variscan low-F biotite and two-mica granites in the German Erzgebirge, in the Saxothuringian Zone of the Variscan Orogen. The group of F-poor biotite granites is represented by the composite massifs of Kirchberg and Niederbobritzsch, the Plohn Granite Suite (PGS), the Aue Granite Suite (AGS), and the subsurface granites of Beiersdorf und Bernsbach. For the group of two-mica granites, compositional data for the multi-stage Bergen massif and the granites from Lauter and Schwarzenberg are reported (Figure 1). Crystal-melt fractionation was the dominant process controlling the evolution of bulk composition in the course of massif/pluton formation. However, metasomatic and hydrothermal processes involving late-stage residual melts and high-T late- to post-magmatic fluids became increasingly more important in highly evolved units and have variably modified the abundances of mobile elements. Interaction with the various metamorphic country rocks and infiltration of meteoric low-T fluids have further disturbed the initial chemical patterns in the endocontact zones and zones influenced by surface weathering. The data set reports whole-rock geochemical analyses for enclaves, granites, aplites, endocontact rocks, and some facial varieties. The data are presented as Excel (xlsx) and machine-readable txt formats. The content of the excel sheet and further information on the granites and regional geology are provided in the data description file.
This data set is Part 9 of a series of data sets dealing with the composition of accessory minerals from felsic igneous rocks compiles chemical data for monazite-(Ce), xenotime-(Y) and zircon from several, late-Variscan granite occurrences in the Aue-Schwarzenberg Granite Zone (ASGZ) located in the Western Erzgebirge−Vogtland metallogenic province of Germany. The rocks treated in this data set encompass the biotite granites of the Aue suite, Bernsbach and Beierfeld, and the two-mica granites from Lauter and the Schwarzenberg suite. The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-ASGZ-2021), xenotime-(Y) (XENO-ASGZ-2021) and zircon (ZIRC-ASGZ-2021). Tables are presented as Excel (xlsx) resp. machine-readable csv formats. The content of the tables and further information on the granites and regional geology are provided in the data description file and the supplementary literature. The ASGZ (about 325 Ma) is located within the deep-reaching Gera-Jáchymov Fault Zone and includes the F-poor biotite granites of the Aue suite (including the granite occurrences at Schlema-Alberoda, Aue, Auerhammer, and Schneeberg), Bernsbach and Beierfeld, and the F-poor two-mica granites of the Schwarzenberg suite (covering the granite occurrences at Schwarzenberg, Neuwelt, and Erla) and Lauter (Fig. 1). The granite encountered by drilling at the village Burkersdorf does not represent an independent intrusion, but is instead a subsurface exposure of the westerly Kirchberg granite, at the contact to the metamorphic country rock. The petrography, mineralogy, geochemistry, isotopic composition, and geochronology of the ASGZ rocks have been comprehensively described by Förster et al. (2009). The paper of Förster (2010) reports a selection of results of electron-microprobe analyses of monazite-(Ce), xenotime-(Y) and zircon, but the bulk of the obtained data remained unpublished. This paper also provides a mineralogical mass-balance calculation for the lanthanides and actinides of the Aue and Schwarzenberg granite suites and a selection of back-scattered electron images displaying the intergrowths, texture, and alteration patterns of the radioactive and REE-Y-Zr-bearing accessory species. The F-poor biotite granites of the ASGZ are weakly to mildly peraluminous (A/CNK = 1.07 – 1.14; SiO2 = 70 – 76 wt.%). The F-poor two-mica granites are mildly to strongly peraluminous (A/CNK = 1.17 – 1.26) and cover a similar range in silica concentration (69 – 77 wt%). From this granite group, only more fractionated, higher evolved sub-intrusions were subjected to the study of accessory-mineral composition. Some granites of this zone are genetically related with ortho-magmatic W-Mo veins and para-magmatic vein-type U mineralization.
This data set is the 1st part of a mini-series assembling whole-rock chemical data for late-Variscan granites of the Erzgebirge-Vogtland metallogenic province in the German Erzgebirge, in the Saxothuringian Zone of the Variscan Orogen, which is dedicated to the group of P-F-rich Li-mica granites. Listed are data from the massifs/plutons of Eibenstock in the western Erzgebirge and Annaberg, Geyer, Pobershau, and Seiffen in the central Erzgebirge (Figure 1). All these occurrences represent composite bodies made-up of texturally and geochemically distinct, but cogenetic sub-intrusions, which are associated with intra- und perigranitic aplitic dykes, pegmatitic schlieren, and frequently mineralized quartz veins and greisens (Tables 1-3). These granites exhibit moderately to strongly elevated concentrations of P, F, Li, Rb, Cs, Ta, Sn, W and U, but are low to very low in Ti, Mg, V, Sc, Co, Ni, Sr, Ba, Y, Zr, Hf, Th, and the REEs. Crystal-melt fractionation was the dominant process controlling the evolution of bulk composition in the course of massif/pluton formation. However, metasomatic processes involving late-stage residual melts and high-T late- to postmagmatic fluids became increasingly more important in highly evolved units and have variably modified the abundances of mobile elements (P, F, Li, Rb, Cs, Ba, Sr). Interaction with the various country rocks and infiltration of meteoric low-T fluids have further disturbed the initial chemical patterns. The data set reports whole-rock geochemical analyses for granites, aplites, and endocontact rocks obtained for the massifs/plutons of Eibenstock, Pobershau, Satzung, Annaberg, and Geyer. Data are provided as separate excel and csv files. The content of the excel sheet and further information on the granites and regional geology are provided in the data description file.
This data set is the part 8 of a series reporting chemical data for accessory minerals from felsic igneous rocks. Compositional data were acquired by electron-probe microanalysis (EPMA) between about 1995 and 2005 on surface rocks and borehole samples. This data set assembles the results of EPMA of fluorapatite from felsic rocks representing three groups of granites in the Erzgebirge−Vogtland metallogenic province of Germany emplaced in the late Carboniferous: F-poor biotite granites, F-poor two-mica granites, and P-F-rich Li-mica granite. In these rocks, fluorapatite is typically omnipresent. It has to be noted that apatite has not yet been in the focus of mineralogical studies of the granites in this province and a comprehensive survey of its compositional signature and variability in space and time is still pending. However, the data listed in this data set provide a valuable glimpse into the similarities and differences in apatite chemistry between geochemically distinct felsic rocks, and into the evolution in composition from early to late crystallizing apatite populations. The data underpin that apatite is a sensitive monitor of the compositional properties of the media (melts and fluids) from which it was deposited or with which it interacted. Apatite from the studied rocks is basically fluorapatite with little or no Cl and OH detected respectively inferred. Elemental variations are observed at various scales, i.e., between granite groups, subsequently crystallized sub-intrusion within composite massifs, grains present in a single thin section, or between the center and the rim of a particular grain. These variations in particular refer to the following elements: Mn, Fe, Na, and the rare-earth elements (REE). For example, measured Mn concentrations range from 0.15 to 8.8 wt% MnO. The data set contains the complete pile of electron-microprobe analyses for fluorapatite (APAT-ERZ-2020). The data are presented as Excel (xlsx) and tab-delimited text (txt) formats. The content of the tables and further information on the granites and regional geology are provided in the data description file.
This dataset contains petrophysical, geochemical, and mineralogical data from a drilling core from the Coastal Cordillera, Chile. The drilling campaign in the semi-arid field site Reserve Santa Gracia was conducted in the framework of the “EarthShape” project (DFG SPP1803) to study deep weathering along a climate gradient. Previous studies in this area found that the weathering front is located much deeper than expected (Oeser et al., 2018). To explore the weathering profile and the depth of the weathering front, we performed various geochemical, petrophysical, and mineralogical analyses. The drilling campaign was conducted in March and April 2019, using the wireline drilling method with a standard industry truck-mounted PQ3-sized (85 mm core diameter, 123 mm hole diameter) rotary drilling rig (Sondajes Araos E.I.R.L.). A detailed description of the drilling activities is given in Krone et al. (2021). The retrieved core runs with a maximum length of 1.5 m were drilled using potable water, with added contamination control tracer for further microbiological analyses of the rock. As basis for our detailed study of deep weathering we determined the porosity, density, specific surface area, elemental composition, mineralogical composition, Fe oxidation, and the degree of weathering from chemical depletion, volumetric strain, and the weathering rate using the in situ cosmogenic nuclide beryllium-10 (10Be).
This dataset is supplementary material to "What controls the presence and characteristics of aftershocks in rock fracture in the lab?" by Joern Davidsen, Thomas H. W. Goebel, Grzegorz Kwiatek, Sergei Stanchits, Jordi Baro and Georg Dresen (Davidsen et al., 2021). The dataset contains source parameters of acoustic emission events recorded during triaxial fracture and friction (stick-slip) experiments performed on two Westerly Granite samples, Aue Granite and Flechtigen Sandstone. Basic seismic catalog associated with each experiment contains origin time, hypocentral location in local Cartesian coordinate system of the sample, acoustic-emission derived magnitude and polarity coefficient (a simplified measure of mechanism type: shear, pore opening or collapse). Extended catalog information is available for selected experiments including information whether event is background seismicity, trigger of following events or triggered by preceding events. In addition, we provide information on focal mechanisms calculated in each experiment using full moment tensor inversion. Focal mechanism catalogs include information on strike, dip and rake of two nodal planes, and percentage of isotropic, clvd and double-couple components of the full moment tensor. The detailed description of catalog is provided in the data description file which is also included in the zip folder of the data.
This data publication contains mineralogical, geochemical and magnetic susceptibility data of an 87.2 m deep profile of hydrothermally altered plutonic rock in a semi-arid region of the Chilean Coastal Cordillera (Santa Gracia). The profile was recovered during a drilling campaign (March and April 2019) as part of the German Science Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota” which aims at understanding weathering of plutonic rock in dependency on different climatic conditions. The goal of the drilling campaign was to recover the entire weathering profile spanning from the surface to the weathering front and to investigate the weathering processes at depth. To this end, we used rock samples obtained by drilling and soil/saprolite samples from a manually dug 2 m deep soil pit next to the borehole. To elucidate the role of iron-bearing minerals for the weathering, we measured the magnetic susceptibility, determined the mineral content and analysed the geochemistry as well as the composition of Fe-bearing minerals (Mössbauer spectroscopy) in selected samples.
| Organisation | Count |
|---|---|
| Wissenschaft | 15 |
| Type | Count |
|---|---|
| unbekannt | 15 |
| License | Count |
|---|---|
| Offen | 15 |
| Language | Count |
|---|---|
| Englisch | 15 |
| Resource type | Count |
|---|---|
| Keine | 15 |
| Topic | Count |
|---|---|
| Boden | 14 |
| Lebewesen und Lebensräume | 14 |
| Luft | 2 |
| Mensch und Umwelt | 15 |
| Wasser | 3 |
| Weitere | 15 |