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.
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.
Die Verwitterung von Mineralen, die Akkumulation organischen Materials und Transportprozesse im Zusammenwirken mit Pflanzen und Bodenleben sind zentrale Parameter der Bodenbildung. Eine Matrix aus feinst- bis nicht-kristallinen Phasen (Oxidhydroxide von Mn, Fe und Al und schlechtkristalline silikatische Neubildungen, haeufig Gele), Tonmineralen und organischen Stoffen, der pH-Wert, das Bodenleben und die Porositaet bestimmen die Bodenfruchtbarkeit, die Eigenschaften des Bodens fuer die Fixierung von Schadstoffen sowie die Qualitaet von Grund- und Oberflaechenwasser. Die komplexe Grenzschicht Mineral-Loesung-Organismus-Luft wurde in zwei ausgewaehlten Verwitterungsprofilen (Loess-Parabraunerde und loessbeeinflusste podsolige Braunerde) mit pauschalchemischen und submikroskopisch aufloesenden Verfahren untersucht, um hochaufgeloeste Informationen zu grundlegenden Mechanismen von Verwitterung und Bodenbildung in unserem Klima zu erhalten. Die Gesamtgehalte an Ca, Na, P und Sr nehmen von der Karbonatgrenze im Loess bei 270 cm nach oben ab, was auf die Verringerung der Apatit- und Plagioklasanteile mit zunehmender Verwitterung hinweist. Im Loessprofil ist die tonangereicherte Matrix zwischen den Mineralkoernern, die sich aus primaer angelieferten Tonmineralen sowie mechanischen und chemischen Verwitterungsprodukten zusammensetzt, gegenueber der Pauschalzusammensetzung stark an Si verarmt und an K, Al, Mg und Fe angereichert (Elektronenstrahl-Mikrosonden-Daten). Ursache ist die Hauptkomponente Illit, die mit Fe-Oxidhydroxiden eng verwachsen ist. Da ein Trend einer systematischen K-Verarmung im Zwischenmittel relativ zu Al im gesamten Verwitterungsprofil nicht festzustellen ist, kann in den letzten 10000 Jahren nicht von einer merklichen Bildung basenaermerer Degradationsprodukte ausgegangen werden. Bei der Faellung von Fe-Oxidhydroxiden werden etwa 20 Mol-Prozent Al in deren Struktur integriert. Diese hohe Al-Anreicherung weist auf durch die Versauerung stark erhoehten Al-Gehalte in der Bodenloesung hin.