Data, images, and R programming language code for age-depth modeling a lake sediment record. Name: Daniel Gavin ORCID: https://orcid.org/0000-0001-8743-3949 Institution: University of Oregon Address: Department of Geography, 1251 University of Oregon, Eugene OR 97403 USA Email: dgavin@uoregon.edu Date of file preparation: 2024-10-11 Date of sediment core collection: 2000-09-15 and 2001-08-24 Geographic location of data collection: 47.637N, 121.888W; Langlois Lake, Carnation, WA USA Funding sources: Packard Foundation Grant to Feng Sheng Hu; University of Oregon sabbatical support to Daniel Gavin Was data derived from another source? No. R code was tested on R 4.3.1. www.R-project.org Citation: Daniel G. Gavin, William T. Struble and Mark A. Fonstad. Holocene Lake Sediments Reveal Alluvial Fan History with Links to Climate, Wildfire, and Earthquakes. Journal of Geophysical Research: Earth Surfaces. Links/relationships to ancillary data sets: Neotoma Paleoecology Database: pollen (doi.org/10.21233/5CJD-9V64), charcoal (doi.org/10.21233/CZNK-ME71), magnetic susceptibility (doi.org/10.21233/B3G8-DC43), loss-on-ignition, and X-ray diffraction (doi.org/10.21233/5PKB-VC34). METHODOLOGICAL INFORMATION Langlois Lake in western Washington contains evidence of overbank flows (floods) onto an alluvial fan surface from the adjacent Tolt River. A six-meter sediment core from the lake, and a freeze core of the surface sediments, reveals the timing of these overbank flows as distinct silt units in the sediment. Radiocarbon dates and Pb-210 measurements provide a basis for aging these layers. However, due to the very different rates of sedimentation of the silt vs organic segments of the core, there is a complicated relationship between depth in the sediment and age of the sediment. Typical methods have simply removed the "slumps" of the rapidly-deposited material; this is a subjective step and difficult to apply for long cores with many such events. The method used here, originally used in two papers (Colombaroli and Gavin 2010, Colombaroli et al. 2018), uses an estimate of the fluvial silt component of sediment (from color or density) as a proxy for sedimentation rate. The R code (R programming language) and data sets here accompany an application of this method to Langlois Lake. We also provide image files of the sediment record which this method depends. Colombaroli, D., & Gavin, D. G. (2010). Highly episodic fire and erosion regime over the past 2,000 y in the Siskiyou Mountains, Oregon. Proceedings of the National Academy of Sciences of the USA, 107(44), 18909–18914. https://doi.org/10.1073/pnas.1007692107 Colombaroli, D., Gavin, D. G., Morey, A. E., & Thorndycraft, V. R. (2018). High resolution lake sediment record reveals self-organized criticality in erosion processes regulated by internal feedbacks. Earth Surface Processes and Landforms, 43(10), 2181–2192. https://doi.org/10.1002/esp.4383) Description These files contain images of the sediment core, the derived color values, and the statistical analysis for developing the flood (silt deposition) chronology. Additional data files are in the Neotoma Paleoecology Database. A full description of the data is in the file readme.txt. The R code (R programming language) is accompanied by comments and designed to be applicable to other sites with little additional customization. The files also contain the input and output for the Pb-210 age depth model applied to the freeze-core sediments, using the package 'serac' in the R programming language. Keywords Age-depth model; radiocarbon; R programming language, lake sediment, flood DATA AND FILE OVERVIEW langlois_freezecore_1.png A compressed composite image of photographs of the freeze core from Langlois Lake. Years are marked in green. langlois_freezecore_2.png The full resolution composite image of the freeze core photographs. No annotations. langlois_freezecore_1867_silt.jpg A photograph of the silt layer occurring near ca. 1867 CE. Photograph taken immediately after coring. ls_composite_150dpi_outliers_trim.png A compressed version of the composite core photographs from Langlois Lake. Data values in file ls_composite_rgb_Lab.csv were obtained from this image. ls_composite_rgb_Lab.csv The measured color values from the core photographs. Measurements were made along transects to avoid voids and other irregularities. silt_model_functions_R.txt The R functions used in the silt-proxy age model. These functions are called in the code in silt_model_workflow_R.txt silt_model_workflow_R.txt The R commands used to compute the silt-proxy age model. Fig5a_silt_decadal.csv The values in Figure 5, showing silt accumulation binned at decadal intervals. While the accuracy of the age model is poorer than decadal, the decade-to-decade variation in fluvial silt accumulation is preserved. Functions for calculating the decadal binned values is in silt_model_workflow_R.txt. Note that Fig 5a displays the 50th percentile age model. langlois_depth_age_model_output.csv The output file of the age model, written by code in silt_model_workflow_R. langlois_serac.zip langlois_varve_measurements.csv The varve thicknesses measured on the upper 26 cm of the freeze core. The following seven files with the s_ prefix are input and output files for the Pb-210 age models using the serac package for R. See help files for the serac package for R. s_langlois_CFCS_interpolation.txt s_langlois_CFCS.txt s_langlois_CRS_interpolation.txt s_langlois_CRS.txt s_langlois_Metadata_2022-05-05.txt s_langlois_varves.txt s_langlois.txt No other versions of these data exist. DATA-SPECIFIC INFORMATION FOR: ls_composite_rgb_Lab.csv Number of variables: 8 Number of rows: 30027 Variable list: Distance_(cm): position within the image. Not used. red, green, blue: red, green, blue intensities on 0-255 scale depth: depth below the sediment-water interface (cm) CIE.L, CIE.a, CIE.b: CIE color space values computed from the RGB values DATA-SPECIFIC INFORMATION FOR: langlois_depth_age_model_output.csv Number of variables: 6 Number of rows: 10201 Variable list: Row number cm: Depth in sediment core (cm) p05: Age at 5th percentile (cal yr BP) p50: Age at 50th percentile (cal yr BP) p95: Age at 95th percentile (cal yr BP) gs: and the lightness value (CIELAB L*), for each 0.05 cm increment. DATA-SPECIFIC INFORMATION FOR: Fig5a_silt_decadal.csv Number of variables: 5 Number of rows: 624 Variable list: row: row in data set yr BP: calibrated radiocarbon years before present p05, p50, p90: estimate of the mm of silt accumulation within a decade for three age models: the 5th, 50th, and 95th percentile range. DATA-SPECIFIC INFORMATION FOR: langlois_varve_measurements.csv Number of variables: 3 Number of rows: 163 Variable list: year: year CE mm: varve thickness in mm depth: depth below sediment-water interface in cm