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.
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.
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.
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.
Objective: various types of contaminated piping, valves, heat exchangers and vessels are removed from nuclear facilities in the course of decommissioning. Depending on their origin, these components are contaminated with various radio nuclides, e.g. alpha-emitters, pure beta-emitters, and gamma-emitters. Unrestricted or otherwise non-hazardous reuse of these components is possible if the residual activity concentrations are below the limits authorised. To achieve this goal, decontamination processes have to be used in general. In many cases, chemical decontamination of large components with complex surface geometry cannot be performed economically. Recycling can be achieved in many cases using melting processes. Thus the non-hazardous reuse of beta-, gamma-contaminated material which accumulated in the course of repairs and refittings of nuclear power plants has been demonstrated by the contractor in co-operation with Siempelkamp Giesserei GmbH und Co, Krefeld. The aim of this research programme is to extend the melt decontamination process to materials which are contaminated with actinides and radio nuclides that are difficult to measure. The distribution of these radio nuclides in the metal and the slag will be determined and direct measuring techniques or representative sampling techniques will be developed. General information: b.1. Literature review related to radio nuclide deposition on components, chemical separation procedures for iron and nickel, basic radio nuclide data and evaluation of authorised activity limits. B.2. Sampling of material and test melts at laboratory scale using well known activity quantities and accompanied by an appropriate measurement programme for original material, metal, slag and off-gas. B.3. Development of direct measuring techniques for alpha emitters in melt and slag, taking into account the alpha-energy of the emitting nuclides and the sample geometry. B.4. Development of measuring techniques for pure beta-emitters, such as c-14 and sr-90, expected to be found in metal and off-gas, and in slag, respectively. B.5. Development of a sampling technique and simple chemical separation procedures for nuclides decaying by electron capture, such as fe-55 and ni-59, emitting weak x-rays which cannot be measured directly. B.6. Large-scale melt in a commercial foundry of alpha-contaminated material to demonstrate the transferability of the laboratory results to industrial scale. B.7. Evaluation of results from both laboratory tests and large-scale tests with respect to alpha-activity distribution in metal, slag and off-gas, the most suitable measuring technique and costs. Achievements: the research work carried out confirmed the expected homogeneous distribution of the radio nuclides selected for the experiments (iron-55 and nickel-63) in the metal ingot, as was already known from the behaviour of cobalt-60. Cobalt-60 radio nuclide may be used as an indicator nuclide for iron-55 and nickel-63 which are both ...
| Origin | Count |
|---|---|
| Bund | 3 |
| Wissenschaft | 9 |
| Type | Count |
|---|---|
| Daten und Messstellen | 6 |
| Förderprogramm | 3 |
| unbekannt | 3 |
| License | Count |
|---|---|
| offen | 12 |
| Language | Count |
|---|---|
| Englisch | 12 |
| Resource type | Count |
|---|---|
| Archiv | 2 |
| Datei | 4 |
| Keine | 5 |
| Webseite | 1 |
| Topic | Count |
|---|---|
| Boden | 6 |
| Lebewesen und Lebensräume | 5 |
| Luft | 4 |
| Mensch und Umwelt | 8 |
| Wasser | 4 |
| Weitere | 12 |