Data for: Transformation of sedimentation patterns in Grønfjorden (Spitsbergen) within the glaciofluvial runoff zone since the end of the Little Ice Age

This archive contains supplementary datasets for the study of sediment stratigraphy, geochronology, and climate change in Grønfjorden (a major branch of Isfjorden, Svalbard) in the post-LIA period. The data were obtained during fieldwork in August 2023 from 5 sediment cores (РК-1, РК-2, КЗ-1, КЗ-3, КЗ-4) collected in the southern part of the fjord within the glaciofluvial runoff impact zone. Cores are labeled as RK_1, KZ_1 etc. in the CSV, XLSX files, which correspond to РК-1, КЗ-1 in the PDF files and associated research article. Sampling Locations (WGS84): 1) РК-1: 77.96904°N, 14.30723°E (Collected 13.08.2023).2) РК-2: 77.97024°N, 14.30108°E (Collected 11.08.2023).3) КЗ-1: 77.96756°N, 14.27446°E (Collected 14.08.2023).4) КЗ-3: 77.98287°N, 14.26203°E (Collected 13.08.2023).5) КЗ-4: 77.99081°N, 14.25200°E (Collected 14.08.2023). Methodology & Data Processing: 1) High-resolution geochronology: ²¹⁰Pb and ¹³⁷Cs gamma-spectrometry (Canberra BE5030 detector).2) Lithological analysis: Grain-size distribution; organic matter content via Loss on Ignition (LOI at 450°C).3) Geochronological modeling: Dates, Linear and Mass Accumulation Rates (SAR/MAR) calculated using CIC, CFCS, and CRS models, with a primary chronological focus on the Constant Flux (CF) modification.4) Meteorological framework: Century-long regional meteorological data (1910–2023) synthesized into composite series from Barentsburg and Longyearbyen stations. Mean annual temperature and precipitation parameters were recalculated over individual layer deposition windows using mean monthly values.5) Sea ice reconstruction: 21st-century ice cover dynamics were tracked using satellite imagery and ice charts (2000–2025). Prior to the satellite era, winter ice severity was retrospectively estimated using cumulative negative monthly air temperatures (October to March).6) Statistical analysis: Spearman’s rank correlation analysis to evaluate how climate changes (temperature, precipitation) modulated sedimentation rates (SAR/MAR) and grain-size parameters. Archive Structure & File Inventory (9 files total): 1) README.pdf - General information, sampling map, archive structure, scientific context, methodological summary, and contact information. Supplementary Dataset 01 (Master Dataset) - Integrated layer-by-layer data combining lithological properties, radioisotope activities, calculated SAR/MAR, and corresponding layer-specific air temperatures and precipitation (raw data for Spearman's correlation analysis):2) Suppl_01_Gronfjorden_Sediment_Cores_Master_Dataset.xlsx (data table with Readme tabs).3) Suppl_01_Gronfjorden_Sediment_Cores_Master_Dataset.csv (data table).4) Suppl_01_Gronfjorden_Grain_Size_Table.pdf (print-ready lithological data).5) Suppl_01_Gronfjorden_Geochronology_MAR_SAR_Table.pdf (print-ready radioisotope measurements (210Pb, 137Cs) and calculated MAR/SAR). Supplementary Dataset 02 (Regional Climate Time Series) - Long-term air temperature records (1913–2025) and sea ice zone extents along the fjord axis (2000–2025):6) Suppl_02_Gronfjorden_Air_Temperature_and_Sea_Ice_TimeSeries.xlsx (data table with Readme tabs).7) Suppl_02_Gronfjorden_Air_Temperature_and_Sea_Ice_TimeSeries.csv (data table). Supplementary Dataset 03 (Statistical Analysis) - Spearman's correlation matrices and statistical significance evaluating climate-sedimentation links.8) Suppl_03_Gronfjorden_Spearman_Correlation_Matrix.xlsx (data table with Readme tabs).9) Suppl_03_Gronfjorden_Spearman_Correlation_Matrix.csv (data table). Detailed methodological descriptions and references are provided within the embedded metadata sheets (Readme tabs) of the respective Excel files.