A compilation of 39,070 published radiometric dates for igneous rocks from the South American Andes and adjacent parts of South America have been tabulated for access by researchers via GEOROC Expert Datasets. The compilation exists as a spreadsheet for access via MS Excel, Google Sheets, and other spreadsheet applications. Initial igneous compilations were utilized in two publications by the author, Pilger (1981, 1984). The compilations have been added to in subsequent years with the metamorphic and sedimentary compilations separated in the last few years. Locations in latitude and longitude are largely taken from the original source, if provided, with UTM locations maintained and converted; in some cases, sample locations were digitized from electronic maps if coordinates were otherwise not available. Analytical results are not included to prevent the files from becoming too large. The existing compilation incorporates compilations by other workers in smaller regions of the Andes. References to original and compilation sources are included. While I am updating reconstructions of the South American and Nazca/Farallon plates, incorporating recent studies in the three oceans, for comparison with the igneous dates for the past 80 m. y., it is hoped that the spreadsheets will be of value to other workers. Reliability: In most cases the data have been copy/pasted from published or appendix tables. In a few cases, the location has been digitized from published maps; the (equatorial equidistant) maps were copied into Google Earth and positioned according to indicated coordinates, with locations digitized and copied/pasted into the spreadsheet. (It is possible that published maps are conventional Mercator-based, even if not so identified, rather than either equatorial equidistant or Universal Transverse Mercator; this can be a source of error in location. For UTMs, the errors should be minor.) Duplicates are largely recognized by equivalent IDs, dates, and uncertainties. Where primary sources have been accessed, duplicate data points in compilations are deleted. (Analytic data are NOT included.) This compilation is part of a series. Companion compilations of radiometric dates from sedimentary and metamorphic rocks are available at https://doi.org/10.5880/digis.e.2023.006 and https://doi.org/10.5880/digis.e.2023.007, respectively.
A compilation of 29,574 published radiometric dates for metamorphic rocks from the South American Andes and adjacent parts of South America have been tabulated for access by researchers via GEOROC Expert Datasets. The compilation exists as a spreadsheet for access via MS Excel, Google Sheets, and other spreadsheet applications. Initial igneous compilations were utilized in two publications by the author, Pilger (1981, 1984). The compilations have been added to in subsequent years with the metamorphic and sedimentary compilations separated in the last few years. Locations in latitude and longitude are largely taken from the original source, if provided, with UTM locations maintained and converted; in some cases, sample locations were digitized from electronic maps if coordinates were otherwise not available. Analytical results are not included to prevent the files from becoming too large. The existing compilation incorporates compilations by other workers in smaller regions of the Andes. References to original and compilation sources are included. While I am updating reconstructions of the South American and Nazca/Farallon plates, incorporating recent studies in the three oceans, for comparison with the igneous dates for the past 80 m. y., it is hoped that the spreadsheets will be of value to other workers. Reliability: In most cases the data have been copy/pasted from published or appendix tables. In a few cases, the location has been digitized from published maps; the (equatorial equidistant) maps were copied into Google Earth and positioned according to indicated coordinates, with locations digitized and copied/pasted into the spreadsheet. (It is possible that published maps are conventional Mercator-based, even if not so identified, rather than either equatorial equidistant or Universal Transverse Mercator; this can be a source of error in location. For UTMs, the errors should be minor.) Duplicates are largely recognized by equivalent IDs, dates, and uncertainties. Where primary sources have been accessed, duplicate data points in compilations are deleted. (Analytic data are NOT included.) This compilation is part of a series. Companion compilations of radiometric dates from igneous and sedimentary rocks are available at https://doi.org/10.5880/digis.e.2023.005 and https://doi.org/10.5880/digis.e.2023.006, respectively.
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 sixth part of a series reporting chemical data for accessory minerals from felsic igneous rocks. It assembles the results of electron-microprobe spot analyses of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan granites of the Fichtelgebirge/Smrčiny in the Saxothuringian Zone of the Variscan Orogen in Germany/ Czech Republic.The granites form an older, Namurian intrusive complex (OIC-p and OIC-e) and a younger, post-Westphalian intrusive complex (YIC-1 and YIC-2). Both complexes have distinct radioactive accessory-mineral assemblages and compositions. The OIC-p biotite monzogranites contain monazite-(Ce) and minor thorite, but apparently lack magmatic xenotime-(Y) and uraninite. The more evolved OIC-e two-mica granites bear monazite-(Ce) occasionally rich in Th (up to 21 wt% ThO2) and U (8 wt% UO2), xenotime-(Y) of moderate U content (< 3.3 wt% UO2), and uraninite poor in Th and the REE. The most fractionated YIC Li-mica granites (YIC-2) may contain monazite extremely high in Th (40.5 wt% ThO2) and U (8.6 wt% UO2), which classify as cheralite-(Ce), xenotime-(Y) rich in U (6.3 wt% UO2) and such with elevated Y/Ho ratios (up to 48), and also a Th–REE-poor uraninite. In these granites, zircon may contain up to 5 wt% HfO2 and display low, fractionated Zr/Hf ratios (down to 10).The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-FICH-2020), xenotime-(Y) (XENO-FICH-2020), and zircon (ZIRC-FICH-2020). All tables are presented as Excel (xlsx) and machine-readable txt formats. The content of the tables and further information on the granites and regional geology are provided in the data description file.
Part seven of a series of data sets dealing with the composition of accessory minerals from felsic igneous rocks reports chemical data for monazite-(Ce) and zircon from eight occurrences of high-Si felsic microgranites/rhyolites in the Erzgebirge−Vogtland metallogenic province of Germany, which possibly emplaced between 305 and 295 Ma. The subvolcanic rocks are discriminated into three groups according to whole-rock geochemistry. Mineral data are acquired between about 1995 and 2005 on surface rocks and borehole samples. The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-VOLC-2020) and zircon (ZIRC-VOLC-2020). All tables are presented as Excel (xlsx) and 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. Information on xenotime-(Y), which is commonly rare and did not precipitate in all rhyolites, and rhabdophane-(Ce), which was observed only ones as alteration product of monazite-(Ce), is provided elsewhere (cf. data description file).
This data set is the 5th fifth part of a series reporting chemical data for accessory minerals from felsic igneous rocks. Most data refer to plutonic rocks from the Saxothuringian Zone of the Variscan Orogen (Erzgebirge−Vogtland metallogenic province) in Germany performed between about 1995 and 2005 on surface rocks and borehole samples.This data set assembles the results of electron-microprobe spot analyses of monazite-(Ce), xenotime-(Y) and zircon from two concealed, genetically distinct occurrences of evolved, F-rich Li-mica granite, that are the transitional S-I-type P-rich granites of Pobershau-Satzung (POB-SZU) and the P-poor granite of Seiffen (SEI), a representative of the class of aluminous A-type granites.Of all three species, grains of abnormal composition are present, reflecting the evolved nature and specific composition of their granite hosts. The most striking differences in mineral composition between the two granite occurrences are displayed by a) the substitution reaction governing the incorporation of Th+U in monazite (cheralite substitution, Ca(Th,U)REE-2, in POB-SZU and huttonite substitution, Th(U)SiREE-1P-1, in SEI) and b) the chondrite-normalized REE patterns of xenotime (peaking at Tb-Dy in POB-SEI and Yb-Lu in SEI).The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-POB-SEI-NBZ2019), xenotime-(Y) (XENO-POB-SEI2019), and zircon (ZIRC-POB-SEI2019). All tables are presented as Excel (xlsx) and 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.
This data set is the third of a series reporting chemical data for accessory minerals from felsic igneous rocks. It compiles the results of electron-microprobe spot analyses of monazite-(Ce) from various Paleoproterozoic granitoids and spatially associated gneisses located in the wider Fort McMurray area in northeastern Alberta, Canada. The data were generated in connection with the Master of Science thesis of Nathanial John Walsh (Walsh 2013) at the Department of Earth and Atmospheric Sciences of the University of Alberta, Edmonton, Canada, but remained unpublished. The thesis was part of the Helmholtz - Alberta - Initiative (HAI) between the University of Alberta and the Helmholtz Association.Interestingly, monazite from the diverse basement rocks display various kinds of pattern with respect to composition and origin. The great bulk of measured grains display variably declined chondrite-normalized LREE patterns virtually free of anomalies indicative for significant fluid-induced overprinting. We have rocks characterized by largely unzoned, chemically homogeneous grains. There are as well rocks containing nicely patchy-zoned grains showing a wide range in composition, in particular regarding the Th/LREE proportions. Here, maximum measured Th concentration amounted to 33 wt% ThO2. Incorporation of Th into the crystal structure is almost exclusively governed by the huttonite substitution reaction, i.e., Th^4+ + Si^4+ = REE^3+ + P^5+, as characteristic for this chemical type of granites (Förster 1998). The suite of rocks also included samples containing small-sized inclusions of Th-poor monazite in apatite, which formed in response to metamorphic, fluid-aided dissolution-reprecipitation processes (Harlov and Förster 2003, Harlov et al. 2005). Finally, we have a quartz monzonite containing Th-poor monazite in apatite together with matrix monazite of normal Th concentration, the origin if which is not yet fully resolved (cf. Foerster-2018-004_monazite-alberta-BSE images.pdf. presenting back-scattered electron images of monazite grains). In brief, the data set provides information on several aspects of formation and alteration of monazite in non-metamorphic and metamorphic granite.The data set published here contains the complete pile of data acquired for monazite-(Ce) and back-scattered electron (BSE) images of many of the probed grains. Chemical data are provided as Excel and machine-readable .csv files, which contain the information listed in Table 1 of the data description file. Column headers in red (only in the Excel version) indicate that the data and information provided in these columns is from Walsh (2013). “0.00” means that the concentrations of the respective elements were measured, but were below their limits of detection. Blank boxes in oxide concentrations columns indicate that the respective elements were not sought. The collection of BSE images is presented as pdf.file. The sample and grain numbers are given below each mineral image and are corresponding to the Sample No. and the Grain No. in the data table.The thesis of N. Walsh "Walsh, N.J. (2013) Geochemistry and geochronology of the Precambrian basement domains in the vicinity of Fort MacMurray, Alberta: a geothermal perspective. Master of Science thesis, Department of Earth and Atmospheric Sciences, University of Alberta, Canada" is not available online.
This data set compiles the results of electron-microprobe spot analyses of monazite-(Ce), xenotime-(Y) and zircon from the two-mica granite massif of Bergen. This massif is composed of compositionally and texturally distinct sub-intrusions, which occasionally contain dark microgranular enclaves and are cross-cut by aplitic dikes. These late-Variscan (c. 325 Ma) granites are evolved, Si-rich (70.6−76.3 wt% SiO2), of transitional I−S-type affinity, and spatially associated with minor W−Mo mineralization.Data indicate that the composition of monazite-(Ce) and zircon changes with fractionation-driven evolution of magma chemistry. In the course of magma differentiation, monazite-(Ce) chemistry evolves towards enrichment Th and U and development of “irregular” chondrite-normalized LREE patterns, with negative anomalies at La or Nd, or both. Monazite-(Ce) precipitated from more evolved magma batches also tends to be richer in MREE and HREE relative to that occurring in early-stage granites. Composition of zircon in more differentiated sub-intrusions displays a large variability. A greater number of grains or domains are distinguished by enrichment in P, Hf, Al, Sc, Y+HREE and low analytical totals, reflecting their crystallization from volatile-rich magmas and/or their interaction with late-magmatic fluids. Xenotime-(Y) chemistry is comparatively insensitive to changes of magma composition that characterized the Bergen massif.The data set published here contains the complete pile of elecron-microprobe analyses for the three accessory minerals monazite-(Ce) (MonaBrg2018), xenotime-(Y) (XenoBRG2018) and zirkon (ZircBRG2018). All tables are presented as Excel (.xlsx) and csv formats. The content of the tables and further data description are given in the data description file.
This data set is the 4th contribution of a series reporting chemical data for accessory minerals from felsic igneous rocks. It deals with two late Variscan biotite-granite massifs emplaced in the Saxothuringian Zone of the Variscan Orogen (Erzgebirge−Vogtland metallogenic province) in Germany. Mineral compositions were measured by electron-microprobe on surface rocks and borehole samples.The data set assembles the results of electron-microprobe spot analyses of primary and secondary allanite-(Ce), monazite-(Ce), xenotime-(Y) and zircon from the multi-phase biotite-granite plutons of Kirchberg (KIB, Western Erzgebirge) and Niederbobritzsch (NBZ, Eastern Erzgebirge). Both plutons comprise several, compositionally and texturally distinct sub-intrusions, contain locally centimeter- to decimeter-sized co-genetic enclaves and xenoliths, and are cross-cut by chemically distinct, fine-grained aplitic dikes. These late-Variscan (c. 325 Ma) granites are moderately to highly evolved and (not considering enclaves) span the SiO2-range (in wt%) 67.0-77.4 (KIB) and 66.8-76.2 (NBZ). The granites are weakly peraluminous (A/CNK = 1.04−1.11 for KIB and 0.99-1.10 for NBZ) and of transitional I−S-type affinity.Formation of primary allanite-(Ce) was restricted to the least-evolved subintrusions KIB1 and NBZ1 of both massifs. All other granites contain monazite-(Ce) as predominant LREE host. Magmatic allanite-(Ce) is variably altered and characterized by totals <100 wt%, implying the presence of several wt% water in the structure. Synchysite-(Ce) constitutes one of its alteration minerals. The Kirchberg massif hosts a second sub-facies of KIB1 that contains monazite instead of allanite as primary species. Severe alteration of this granite facies gave rise to partial or complete dissolution of part of the monazite accompanied by formation of allanite-epidote solid solutions as alteration product. Monazite-(Ce) displays large variations in Th versus REE concentrations even at thin-section scale. Incorporation of Th is mainly governed by the huttonite substitution Th^4+ + Si^4+ = REE^3+ + P^5+. Thorium concentrations span the range 1.33 – 41.8 wt.% ThO2. Xenotime-(Y) does not occur in KBI1 and NBZ1, but crystallized in all other subintrusions. Notable is the predominance of the heaviest REE Er-Lu (normalized to chondrite).The data set contains the complete pile of electron-microprobe analyses for the four accessory minerals allanite-(Ce) (ALLA-KIB-NBZ2019), monazite-(Ce) (MONA-KIB-NBZ2019), xenotime-(Y) (XENO-KIB-NBZ2019) and zircon (ZIRC-KIB-NBZ2019). All tables are presented as Excel (xlsx) and machine-readable csv formats. The content of the tables and further data description are given in the data description file, together with BSE images of primary and secondary allanite-(Ce) from the KIB1 subintrusion.
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