112 documents found in 376ms
# 1
Dietze, Elisabeth • Dietze, Michael
Abstract: EMMA – End Member Modelling Analysis of grain-size data is a technique to unmix multimodal grain-size data sets, i.e., to decompose the data into the underlying grain-size distributions (loadings) and their contributions to each sample (scores). The R package EMMAgeo contains a series of functions to perform EMMA based on eigenspace decomposition. The data are rescaled and transformed to receive results in meaningful units, i.e., volume percentage. EMMA can be performed in a deterministic and two robust ways, the latter taking into account incomplete knowledge about model parameters. The model outputs can be interpreted in terms of sediment sources, transport pathways and transport regimes (loadings) as well as their relative importance throughout the sample space (scores).
# 2
Brugger, Julia • Hofmann, Matthias • Petri, Stefan • Feulner, Georg
Abstract: In "On the sensitivity of the Devonian climate to continental configuration, vegetation cover, orbital configuration, CO_2 concentration and insolation" we study the sensitivity of the Devonian (419 to 359 million years ago) to several parameters using a coupled climate model. The data presented here is the model output the results of this manuscript are based on. Additionally, the figures of the publication and scripts (Python and Yorick) to analyse the model output and generate the figures are contained. The model output is provided in different netcdf files. The structure of the model output is explained in a readme file. The data is generated using the coupled ocean-atmosphere model CLIMBER3alpha which models climate globally on a 3.75°x3.75° (ocean) and 22.5° (longitude) x 7.5° (latitude) (atmosphere) grid. More information about the model can be found in the manuscript.
# 3
Blanchet, Cécile L.
Abstract: The database presented here contains radiogenic neodymium and strontium isotope ratios measured on both terrestrial and marine sediments. It was compiled to help assessing sediment provenance and transport processes for various time intervals. This can be achieved by either mapping sediment isotopic signature and/or fingerprinting source areas using statistical tools (see supplemental references). The database has been built by incorporating data from the literature and the SedDB database and harmonizing the metadata, especially units and geographical coordinates. The original data were processed in three steps. Firstly, a specific attention has been devoted to provide geographical coordinates to each sample in order to be able to map the data. When available, the original geographical coordinates from the reference (generally DMS coordinates, with different precision standard) were transferred into the decimal degrees system. When coordinates were not provided, an approximate location was derived from available information in the original publication. Secondly, all samples were assigned a set of standardized criteria that help splitting the dataset in specific categories. We defined categories associated with the sample location ("Region", "Sub-region", "Location", which relate to location at continental to city/river scale) or with the sample types (terrestrial samples – “aerosols”, “soil sediments”, “river sediments” - or marine samples –“marine sediment” or “trap sample”). Thirdly, samples were discriminated according to their deposition age, which allowed to compute average values for specific time intervals (see attached table "Age_determination_Sediment_Cores.csv"). The dataset will be updated bi-annually and might be extended to reach a global geographical extent and/or add other type of samples. This dataset contains two csv tables: "Dataset_Nd_Sr_isotopes.csv" and "Age_determination_Sediment_Cores.csv". "Dataset_Nd_Sr_isotopes.csv" contains the assembled dataset of marine and terrestrial Nd and/or Sr concentration and isotopes, together with sorting criteria and geographical locations. "Age_determination_Sediment_Cores.csv" contains all background information concerning the determination of the isotopic signature of specific time intervals (depth interval, number of samples, mean and standard deviation). Column headers are explained in respective metadata comma-separated files. A human readable data description is provided in portable document format, as well. Finally, R code for mapping the data and running statistical analyses is also available for this dataset (see supplemental references).
# 4
Blanchet, Cécile L.
Abstract: The database presented here contains radiogenic neodymium and strontium isotope ratios measured on both terrestrial and marine sediments. It was compiled to help assessing sediment provenance and transport processes for various time intervals. This can be achieved by either mapping sediment isotopic signature and/or fingerprinting source areas using statistical tools (e.g. Blanchet, 2018b, 2018a). The database has been built by incorporating data from the literature and the SedDB database and harmonizing the metadata, especially units and geographical coordinates. The original data were processed in three steps. Firstly, a specific attention has been devoted to provide geographical coordinates to each sample in order to be able to map the data. When available, the original geographical coordinates from the reference (generally DMS coordinates, with different precision standard) were transferred into the decimal degrees system. When coordinates were not provided, an approximate location was derived from available information in the original publication. Secondly, all samples were assigned a set of standardized criteria that help splitting the dataset in specific categories. We defined categories associated with the sample location ("Region", "Sub-region", "Location", which relate to location at continental to city/river scale) or with the sample types (terrestrial samples – “aerosols”, “soil sediments”, “river sediments”, “rocks” - or marine samples –“marine sediment” or “trap sample”). Thirdly, samples were discriminated according to their deposition age, which allowed to compute average values for specific time intervals (see attached table "Age_determination_Sediment_Cores_V2.txt"). A first version of the database was published in September 2018 and presented data for the African sector. A second version was published in April 2019, in which the dataset has been extended to reach a global extent. The dataset will be further updated bi-annually to increase the geographical resolution and/or add other type of samples. This dataset consists of two tab separated tables: "Dataset_Nd_Sr_isotopes_V2.txt" and "Age_determination_Sediment_Cores_V2.txt". "Dataset_Nd_Sr_isotopes_V2.txt" contains the assembled dataset of marine and terrestrial Nd and/or Sr concentration and isotopes, together with sorting criteria and geographical locations. "Age_determination_Sediment_Cores_V2.txt" contains all background information concerning the determination of the isotopic signature of specific time intervals (depth interval, number of samples, mean and standard deviation). Column headers are explained in respective metadata comma-separated files. A full reference list is provided in the file “References_Database_Nd_Sr_isotopes_V2.rtf”. Finally, R code for mapping the data and running statistical analyses is also available for this dataset (Blanchet, 2018b, 2018a).
# 5
Caricchi, Chiara • Lucchi, Renata Giulia • Sagnotti, Leonardo • Macrì, Patrizia • Di Roberto, Alessio • (et. al.)
Abstract: This data publication includes the paleomagnetic and rock magnetic dataset from two Calypso giant piston cores collected at the crest of the Bellsund (GS191-01PC) and Isfjorden (GS191-02PC) sediment drifts during the Eurofleets-2 PREPARED cruise, on board the R/V G.O. Sars (Lucchi et al., 2014). These sediments drift are located on the eastern side of the Fram Strait (western Spitsbergen margin).The dataset gave the opportunity to define the behavior of past geomagnetic field at high latitude and to constrain the palaeoclimatic events that occurred in a time framework spanning Marine Isotope Stage (MIS) 3 to Holocene (Caricchi et al., in press). The data are provided as raw data in .dat format and interpreted data in .xlx and tab-delimited text formats. The raw data files can be opened using a text-editor, MS Excel or equivalent software. The interpreted data are presented as a metadata table with definitions of the column heads and 5 individual tables with the content: - Metadata: definition of columns heads - Rock Magnetic-Paleomag Data 01: down-core variation of rock magnetic and paleomagnetic parameters [k (10E-05 SI); ARM (A/m); ARM/k (A/m); MDF (mT); ΔGRM/ΔNRM; NRM (A/m); MAD (°); Incl PCA (°); Decl PCA (°)] for Core GS191-01PC - Rock Magnetic-Paleomag Data 02: down core variation of rock magnetic and paleomagnetic data [k (10E-05 SI); ARM (A/m); ARM/k (A/m); MDF (mT); ΔGRM/ΔNRM; NRM (A/m); MAD (°); Incl PCA (°) Decl PCA (°)] for Core GS191-02PC - Cores Correlation: Depth of Core GS191-02PC and depth of Core GS191-02PC correlated to Core GS191-01PC, NRM (A/m); ARM(A/m) and RPI down-core variations for core GS191-02PC; Depth of Core GS191-01PC NRM (A/m); ARM(A/m) and RPI down-core variations for core GS191-01PC; tie points values. - Age Model 01: age model for Core GS191-01PC - Age Model 02: age model for Core GS191-01PC
Raw data were measured at the paleomagnetic laboratory of INGV and have been analysed by DAIE software (Sagnotti, 2013). The obtained along-core variation of rock magnetic and paleomagnetic trends have been integrated with the distribution of characteristic lithofacies and the 14C ages in order to define high-resolution correlation between the cores. Core to core correlation has been computed by means of StratFit software (Sagnotti and Caricchi, 2018). The correlation process is based on the Excel forecast function and linear regression between subsequent couples of selected tie-points. This process results in the estimate of the equivalent depth of the correlated curve (core GS191-02 PC) into the depth scale of the “master” curve (GS191-01PC). Using the same method and taking into account the constraints provided by the calibrated radiocarbon ages and the litostratigraphic information, PREPARED cores have been compared to RPI and inclination variations expected at the core sites according to global geomagnetic field models (SHA.DIF.14k of Pavón-Carrasco et al., 2014; GGF.110k of Panovska et al., 2018).
# 6
Weber, Tobias • Thomas, Maik
Abstract: These data are supplementary material to the manuscript "Influence of ocean tides on the general ocean circulation in the early Eocene" (T. Weber, M. Thomas, Paleoceanography, http://doi.org/10.1002/2016PA002997). It contains atmospheric and oceanic variables as simulated by the coupled atmosphere-ocean model ECHAM5/ MPIOM for the early Eocene (55 million years ago) and a pre-industrial simulation representing climate conditions at 1850 AD. Simulations are performed without and with tidal forcing of the ocean. The files are available in the zip folder in NetCDF and .txt formats (subfolder MHT). An overview on the available files and their content is given in the README.
# 7
Lauterbach, Stefan • Brauer, Achim • Andersen, Nils • Danielopol, Dan • Dulski, Peter • (et. al.)
Abstract: Investigation of the sedimentary record of pre-Alpine Lake Mondsee (Upper Austria) focused on the environmental reaction to rapid Lateglacial climatic changes. Results of this study reveal complex proxy responses that are variable in time and influenced by the long-term evolution of the lake and its catchment. A new field sampling approach facilitated continuous and precisely controlled parallel sampling at decadal to sub-annual resolution for m-XRF element scanning, carbon geochemistry, stable isotope measurements on ostracods, pollen analyses and large-scale thin sections for microfacies analysis. The Holocene chronology is established through microscopic varve counting and supported by accelerator mass spectrometric 14C dating of terrestrial plant macrofossils, whereas the Lateglacial age model is based on d18O wiggle matching with the Greenland NGRIP record, using the GICC05 chronology. Microfacies analysis enables the detection of subtle sedimentological changes, proving that depositional processes even in rather large lake systems are highly sensitive to climate forcing. Comparing periods of major warming at the onset of the Lateglacial and Holocene and of major cooling at the onset of the Younger Dryas reveals differences in proxy responses, reflecting threshold effects and ecosystem inertia. Temperature increase, vegetation recovery, decrease of detrital flux and intensification of biochemical calcite precipitation at the onset of the Holocene took place with only decadal leads and lags over a ca. 100 a period, whereas the spread of woodlands and the reduction of detrital flux lagged the warming at the onset of the Lateglacial Interstadial by ca. 500-750 a. Cooling at the onset of the Younger Dryas is reflected by the simultaneous reaction of d18O and vegetation, but sedimentological changes (reduction of endogenic calcite content, increase in detrital flux) were delayed by about 150-300 a. Three short-term Lateglacial cold intervals, corresponding to Greenland isotope substages GI-1d, GI-1c2 and GI-1b, also show complex proxy responses that vary in time.
# 8
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 9
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 10
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
spinning wheel Loading next page