Sediment Data From Cores Collected in 2025 at Midnight Pass, Florida

Cores were collected using a Skidril© G2XD-4 mechanical post driver. The aluminum core barrel was fitted to the post driver using an 8.25 cm adapter, and the core barrel was driven into the subsurface until refusal, or full penetration of barrel. Measurements were taken on the inside and outside of the core barrel prior to extraction to determine the amount of compaction, which is the difference between the recovered core length and the total depth the core barrel penetrated below the sediment surface. After extraction, each core was capped, sealed, and labeled with the core number and orientation. All cores were transported to the SPCMSC sediment laboratory for processing and analysis. Core collection information was compiled into a comma-separated values file (.csv), and is included in the data download zip file, 2024-330-FA_MP_CoreSites.zip of this data release.

Core processing and photographing: At the SPCMSC sediment laboratory, the cores were split lengthwise and photographed. The split cores were photographed in approximately 20- to 25-cm, overlapping segments with a Nikon© D80 digital camera with a 70-millimeter (mm) zoom lens using consistent (manually programmed) settings with autofocus from a fixed height. The raw images were white-balanced using GNU Image Manipulation Program (GIMP) version 2.10 software, cropped to the same extent (to remove areas outside of the core barrel), and "stitched" together using The Panorama Factory version 4.5 software, providing seamless high-resolution whole-core Joint Photographic Experts Group (JPEG, .jpg) images. Lithologic descriptions for the core logs are based on macroscopic observations. Sediment color is based on the Munsell soil color system (https://munsell.com/color-products/color-communications-products/environmental-color-communication/munsell-soil-color-charts/). Descriptive core logs for the seven cores were compiled using RockWare® LogPlot 8 software, edited in Adobe Illustrator, and exported as JPEG images. The filenames for each core photo are as follows: survey location name ('MP', for Midnight Pass), followed by a number for the transect (2 or 3, where 2 is north of the inlet and 3 is south), a dash, and then letter for the core site (B, D, E, F, or G). Example: MP2-D.jpg. The core logs follow the same naming convention as the core photos, with the addition of the FAN and a dash at the beginning (example: 2024-330-FA-MP2-D.jpg). These images are available in their respective data download zip file, 2024-330-FA_MP_CorePhotos.zip and 2024-330-FA_MP_CoreLogs.zip.

Grain-size processing: The raw grain-size data was run through the free software GRADISTAT version 9, (Blott and Pye, 2001), which calculates the mean, sorting, skewness and kurtosis of each sample geometrically, in metric units, and logarithmically, in phi (Φ) units (Krumbein, 1934), using the Folk and Ward (1957) scale. GRADISTAT also reports the descriptive sediment texture after Folk (1954) and calculates the fraction of sediment from each sample by size category (for example, mud, coarse sand, fine gravel) based on a modified Wentworth (1922) size scale. The results for all samples, including multiple samples derived from selected intervals for quality control purposes, are included as a tab in a Microsoft Excel workbook (2024-330-FA_MP_GrainSizeStats.xlsx) and as a comma-separated values (2024-330-FA_MP_SieveStats.csv) data file.

Grain-size sieve analysis: Sediment samples were analyzed by dry sieving. The sediment was passed through a stack of sieves with progressively smaller openings using the assistance of a mechanical sieve shaker to determine grain-size distribution. U.S. standard sieves numbers 230 (63 micrometers [µm]), 120 (125 µm), 60 (250 µm), 35 (500 µm), 18 (1 millimeters [mm]), 10 (2 mm), 5 (4 mm), and 5/16" (8 mm) were used, which meet the ASTM E11 standard specifications for determining particle size using woven-wire test sieves. All dry-sieve data was reported as a percent fraction of the total bulk dry weight of each sample subset. The results for all samples are included as a tab in an Excel workbook (2024-330-FA_MP_GrainSizeStats.xlsx) and as a comma-separated values (2024-330-FA_MP_SieveStats.csv) data file.

Populating image headers: Additional metadata were added to the exchangeable image file format (EXIF) header of each image using Phil Harvey’s ExifTool version 12.30 (Harvey, 2021). The image headers were populated individually for each of the seven core photos and seven core logs. The information in the scripts were the same among all images, aside from the EXIF:ImageDescription, EXIF:GPSLatitude, and EXIF:GPSLongtitude information, as that information varied for each core. The EXIF:ImageDescription and IPTC:Keywords information varies between the core photos and core logs as well. An example script for core photo MP3-E.jpg is provided below. First, the following command was run on all images in a folder to preserve filenames: exiftool -P "-XMP:PreservedFileName<Filename" *.JPG.
Second, the following command was run for core photo MP3-E.jpg: exiftool -IPTC:Credit="U.S. Geological Survey" -IPTC:Contact="gs-g-spcmsc_data_inquiries@usgs.gov" -EXIF:Copyright="Public Domain" -XMP:UsageTerms="Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty." -EXIF:ImageDescription="https://cmgds.marine.usgs.gov/services/activity.php?fan=2024-330-FA; Photograph of core MP3-E collected at Midnight Pass, between Siesta Key and Casey Key, Florida, from USGS field activity 2024-330-FA." -XMP:AttributionURL="https://doi.org/10.5066/P1CQ6QRR" -EXIF:GPSAreaInformation="Trimble SPS986 and Leica GS16 RTK (Real-time Kinematic), cm-accuracy" -XMP:ExternalMetadataLink="https://www1.usgs.gov/pir/api/identifiers/USGS:cd72480c-1dc9-48b6-a150-955ed04d59ee" -EXIF:GPSMapDatum="EPSG:4326 (WGS 84)" -EXIF:Artist="Daniel Ciarletta (USGS) & Blake Smullen (Contractor to the USGS)" -EXIF:Make="Nikon" -EXIF:Model="D80" -EXIF:GPSLatitude="27.20765771" -EXIF:GPSLatitudeRef="N" -EXIF:GPSLongitudeRef="W" -EXIF:GPSLongitude="-82.5111425" -sep ";" -IPTC:Keywords="drilling and coring, unconsolidated deposits, field sampling" -overwrite_original -P MP3-E.jpg
Third, the following command run on all images in a folder to copy information into duplicate tags: exiftool -P "-XMP-photoshop:Credit<IPTC:Credit" "-XMP-iptcCore:CreatorWorkEmail<IPTC:Contact" "-XMP-dc:Rights<EXIF:Copyright" "-XMP-dc:Description<EXIF:ImageDescription" "-XMP-exif:all" "-XMP-photoshop:DateCreated<EXIF:DateTimeOriginal" -overwrite_original *.JPG
To extract the information from the image headers using ExifTool, run the following command after connecting to the unzipped folder containing the images: exiftool -n -csv *.jpg > allheaders.csv