Repeated Early Holocene eruptions of Katla, Iceland, limit the temporal resolution of the Vedde Ash

High-resolution Holocene record from Torfdalsvatn, north Iceland, reveals natural and anthropogenic impacts on terrestrial and aquatic environments

“…Plant sedaDNA records from Torfdalsvatn indicate that the first pioneer forb, graminoid and bryophyte taxa were present in the catchment no earlier than 12,000 cal a BP (Fig. 7c, Alsos et al, 2021;Harning et al, 2024). The lack of a substantial terrestrial ecosystem needed to stabilize the landscape at this time is consistent with the highest MS values in Torfdalsvatn's Holocene record (Fig.…”

“…Detailed tephra layer descriptions (n = 33), compositional datasets (>2200 grains analyzed), and elemental plots used to identify the tephra layers are provided in the Supporting Data and Information. We 185 stress, unless otherwise noted, that our chemical data is obtained from pristine basaltic to silicic tephra grains that feature delicate protrusions (e.g., Harning et al, 2024). In samples regarded as representing pristine tephra fall, the grains in the mafic realm (basalt to andesite) range from (i) non-to poorly (<20 %) vesicular, black blocky glass grains defined by brittle fracture surfaces to (ii) poorly-to highly-vesicular (20 to 60 %) black to brown glass grains with vesicle-pitted surfaces to (iii) highly vesicular (>60 %) translucent (sideromelane), brown to pale brown glass grains with very convolute outlines to (iv) achneliths 190 defined by coherent shiny black glazed/fused outer surfaces (e.g., Walker and Croasdale, 1972;Thordarson et al, 1996).…”

“…1). Due to it being the only known non-marine sedimentary record in Iceland that extends to ≤12000 cal a BP, its lacustrine record has attracted considerable attention (e.g., Björck et al, 1992;Rundgren, 1995Rundgren, , 1998Rundgren and Ingólfsson, 1999;Florian, 2016;Alsos et al, 2021;Harning et al, 2024). Important contributions include the major elemental composition of regional marker tephra layers (Björck et al, 1992;Alsos et al, 2021), which for the Early Holocene section have been recently revised (Harning et al, 2024).…”

“…CC BY 4.0 License.1 Abbreviation in the tephra ID column are as follows: A, Askja: C, cryptotephra; G, Grímsvötn; H, Hekla; K, Katla; Kv, Kverkfjöll; V-B, Veiðivötn-Bárðarbunga.2 Refers to depth in 2012NC sediment core. 3 Ages reported inHarning et al (2024).4 Indicates number of tephra fall events represented within individual tephra horizons. Total is 78.…”