This README.txt file was generated on 2023-09-08 by QUESNEL Yoann It describes the information about the datasets accompanying the study of Quesnel et al. on the Velingara depression, a possible impact structure in Senegal. GENERAL INFORMATION 1. Title of Datasets: VelingaraData 2. Author Information Name: QUESNEL Yoann Institution: Aix-Marseille University, CEREGE, France Address: CEREGE, Technopole de l'Arbois Mediterranee, BP80, 13545 Aix-en-Provence cedex 04, France Email: quesnel@cerege.fr 3. Date of data collection (single date, range, approximate date): 2022-03 4. Geographic location of data collection: 13.04°N, 14.13°W, nearby Velingara, Senegal 5. Information about funding sources that supported the collection of the data: CNRS INSU PNP CNRS AWA CNES IRD SHARING/ACCESS INFORMATION 1. Licenses/restrictions placed on the data: will be public after publication of the corresponding article 2. Links to publications that cite or use the data: (coming soon) 3. Links to other publicly accessible locations of the data: 4. Links/relationships to ancillary data sets: 5. Was data derived from another source? no A. If yes, list source(s): Bureau Gravimétrique International (BGI) / IAG International Gravity Field Service 6. Recommended citation for this dataset: (coming soon) DATA & FILE OVERVIEW File List: MagneticFieldData.csv: ground magnetic field intensity measurements GravimetricData.csv: Bouguer gravimetric anomaly data LAICPMS-results.csv: results of LA-ICP-MS on zircon grains METHODOLOGICAL INFORMATION 1. Description of methods used for collection/generation of data: Magnetic Field Data: ground survey using MMPOS-1 magnetometer at ~2 m height, and associated GPS device Gravimetric Data: ground survey using a Scintrex CG-5 gravimeter, and a dGPS system for precise positioning LAICPMS Data: U-Pb analysis of Velingara zircon grains by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), using a RESOlution-SE incorporating a COMPex 102 excimer laser, coupled to an Agilent 8900 QQQ ICP-MS at the GeoHistory Facility in the John de Laeter Centre at Curtin University, Australia 2. Methods for processing the data: Magnetic Field Data: the internal and external global magnetic field influences were removed using our own base station, then filtering and detrending were applied on this anomaly dataset. Gravimetric Data: the drift of the gravimeters was removed using regular return-to-the-base during the survey; all data were leveled to a single reference point, and then classical gravimetric corrections were applied to extract the complete Bouguer gravimetric anomaly, using a regional crustal density of 2700 kg/m3 LAICPMS Data: Time-resolved mass spectra were reduced using the U-Pb Geochronology data reduction scheme in Iolite 4 (Paton et al., 2010, 2011). The primary zircon dating reference material used was 91500 (1062.4 ± 0.4 Ma; Wiedenbeck et al., 1995), with GJ-1 (608.53 ± 0.37 Ma; Jackson et al., 2004), OG1 (3465.4 ± 0.6 Ma; Stern et al., 2009), Plešovice (337.13 ± 0.37 Ma; Sláma et al., 2008) and RAK-17 (295.56 ± 0.21 Ma; Webb et al., 2020) analyzed as secondary age standards. Concordia ages (Ludwig, 1998) calculated for the zircon age standards were found to be within 1% of accepted values. All ages are quoted at 2σ absolute uncertainty. Various discordance filters were evaluated (e.g., 90-110% and similar ranges with increments of 10%), and while the age peaks became better defined with more restrictive discordance filters, no significant shift in the mean value of each age population was detected. In the interest of displaying the full data set, we chose not to apply a discordance filter. The data were not corrected for common Pb, given the challenges of accurately determining the contribution of common Pb to measured 204Pb values. Excluding grain Z1, there is little evidence for significant common Pb contributions to the majority of anlayzed grains; nearly the entire data set (except for 4 of 98 grains) lies on the Concordia curve. 3. Environmental/experimental conditions: the gravimetric and magnetic measurements were acquired during March, with warm conditions (~40°C at noon), in savannah and swamps. The LAICPMS measurements were done at the GeoHistory Facility in the John de Laeter Centre at Curtin University, Australia 4. People involved with sample collection, processing, analysis and/or submission: see the associated publication DATA-SPECIFIC INFORMATION FOR: MagneticFieldData.csv 1. Number of variables: 4 2. Number of cases/rows: 2252 3. Variable List: Lon: Longitude (°E) Lat: Latitude (°N) Ano: Magnetic field anomaly (nT) DtrAno: Detrended magnetic field anomaly (nT) DATA-SPECIFIC INFORMATION FOR: GravimetricData.csv 1. Number of variables: 4 2. Number of cases/rows: 230 (154 from our survey + 76 from BGI dataset) 3. Variable List: Lon: Longitude (°E) Lat: Latitude (°N) Elev: Surface Elevation (m) (WGS84 datum) BA: Bouguer anomaly (mGal) DtrBA: Detrended Bouguer anomaly (mGal) 4. Missing data codes: - DATA-SPECIFIC INFORMATION FOR: LAICPMS-results.csv 1. Number of variables: 47 2. Number of cases/rows: 235 3. Variable List: Sample: sample ID Duration: duration of laser ablation (s) Pb206_Pb204_Hgcorr_mean: [Pb206]/[Pb204] mean value, corrected from [Hg201] Pb206_Pb204_Hgcorr_2SE_int: 2 sigma standard deviation (int) from [Pb206]/[Pb204] mean value, corrected from [Hg201] Pb206_Pb204_mean: [Pb206]/[Pb204] mean value Pb206_Pb204_2SE_int: 2 sigma standard deviation (int) from [Pb206]/[Pb204] mean value Pb208_Pb206_mean: [Pb208]/[Pb206] mean value Pb208_Pb206_2SE_int: 2 sigma standard deviation (int) from [Pb208]/[Pb206] mean value Final_Pb206_U238_mean: final [Pb206]/[U238] mean value Final_Pb206_U238_2SE_int: 2 sigma standard deviation (int) from final [Pb206]/[U238] mean value Final_Pb206_U238_2SE_prop: 2 sigma standard deviation (prop) from final [Pb206]/[U238] mean value Final_age_Pb206_U238_mean: final age (Ma) from [Pb206]/[U238] mean value Final_age_Pb206_U238_2SE_int: 2 sigma standard deviation (int) final age (Ma) from [Pb206]/[U238] mean value Final_age_Pb206_U238_2SE_prop: 2 sigma standard deviation (prop) final age (Ma) from [Pb206]/[U238] mean value then the 18 next columns are similar to the last 6 columns with mean and 2SD values (int and prop) of different isotopic ratio and associated ages for [Pb207]/[U235], [Pb208]/[Th232], [Pb207]/[Pb206] Final_U238_Pb206_mean: final [U238]/[Pb206] mean value Final_U238_Pb206_2SE_int: 2 sigma standard deviation (int) from final [U238]/[Pb206] mean value Final_U238_Pb206_2SE_prop: 2 sigma standard deviation (prop) from final [U238]/[Pb206] mean value Th/U: [Th]/[U] ratio Final_U_Th_mean: final [U]/[Th] mean value Final_U_Th_2SE_int: 2 sigma standard deviation (int) from final [U]/[Th] mean value Approx_U_PPM_mean: approximative mean value of [U] in ppm Approx_U_PPM_2SE_int: 2 sigma standard deviation from approximative mean value of [U] in ppm the 2 next columns are similar the last 2 columns for Th and Pb rho_206Pb_238U_v_207Pb_235U: ([Pb206]/[U238])/([Pb207]/[U235]) value rho_207Pb_206Pb_v_238U_206Pb: ([Pb207]/[Pb206])/([U238]/[Pb206]) value Discordance_238U_206Pb_age_v_207Pb_206Pb_age_m100: [([U238]/[Pb206] age)/([Pb207]/[Pb206])]*100 value