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Radiometric Dates from the South American Andes and Adjacent Areas: A Compilation - part 2 sedimentary rocks

A compilation of 90,688 published radiometric dates for sedimentary 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 metamorphic rocks are available at https://doi.org/10.5880/digis.e.2023.005 and https://doi.org/10.5880/digis.e.2023.007, respectively.

Radiometric Dates from the South American Andes and Adjacent Areas: A Compilation - part 1 igenous rocks

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.

Radiometric Dates from the South American Andes and Adjacent Areas: A Compilation - part 3 metamorphic rocks

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.

Radiocarbon measurements on tree rings of tree MWK85-05B

Radiocarbon measurements on tree rings of tree M49

Radiocarbon measurements on tree rings (7220-7122 BCE and 5300-5190 BCE)

Accelerator mass spectrometer measurement results of C14 age in tree rings from 13 different dendrochronoligically dated trees from Ireland and the Alps, United states and Siberia, spanning from 7220-7122 BCE and 5300-5190 BCE. The Sun sporadically produces eruptive events leading to intense fluxes of solar energetic particles (SEPs) that dramatically disrupt the near-Earth radiation environment. Such events have been directly studied for the last decades but little is known about the occurrence and magnitude of rare, extreme SEP events. Presently, a few events that produced measurable signals in cosmogenic radionuclides such as 14C, 10Be and 36Cl have been found. Analyzing annual 14C concentrations in tree-rings from Switzerland, Germany, Ireland, Russia, and the USA we discovered two spikes in atmospheric 14C corresponding to 7176 and 5259 BCE. The ~2% increases of atmospheric 14C recorded for both events exceed all previously known 14C peaks but after correction for the geomagnetic field, they are comparable to the largest event of this type discovered so far at 775 CE. These strong events serve as accurate time markers for the synchronization with floating tree-ring and ice core records and provide critical information on the previous occurrence of extreme solar events which threaten modern infrastructure.

Radiocarbon measurements on tree rings of tree ZH-600797

Radiocarbon measurements on tree rings of tree ZH-644415

Radiocarbon measurements on tree rings (969-1933 AD)

Accelerator mass spectrometer measurement results of C14 age in tree rings from 13 different dendrochronoligically dated trees from England and Switzerland spanning the last almost all of the last millenium. The Sun provides almost all of the external forcing to the Earth system, so that its variability is of considerable interest for geoscience. Observational records of solar activity cover only the last about 400 yr. Beyond that, cosmogenic nuclides stored in tree rings (14C) or ice cores (10Be, 36Cl) are used as proxies for solar activity extending back by many thousands of years1-3. Major drawbacks of cosmogenic nuclide based solar reconstructions are the presence of weather-induced noise (10Be in ice cores) and/or low temporal resolution of long, precisely dated records (14C in tree rings). Here, we present a continuous, annually resolved 14C record from absolutely dated tree rings covering nearly all of the last millennium (969-1933 AD). The high resolution and high precision 14C record reveals the presence of the eleven-year solar Schwabe cycle over the past millennium. Statistical analysis of the Schwabe cycle shows a positive correlation of its amplitude with reconstructed solar modulation. The record further confirms the 993 AD solar energetic particle event and reveals two new candidate events (1052 AD and 1279 AD) indicating that strong solar events are probably more common than previously thought.

Forschergruppe (FOR) 668: Datierte Speläotheme: Archive der Paläoumwelt; Research group (FOR) 668: Dated Speleothems: Archives of the Paleoenvironment, 14C in speleothems

Using the absolute age of speleothem samples from Th/U-dating, we can determine their 14C reservoir age. The 14C reservoir age is controlled mainly by pCO2 in the unsaturated soil zone, the ratio of root respiration (with modern 14C levels) and microbial decomposition of soil organic matter (depleted in 14C due to radioactive decay). The main factors governing soil conditions are soil temperature and precipitation. Hence, variations in the 14C reservoir age provide information on the variability of these two climate variables.

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