Holocene tephra from Iceland and Alaska in SE Greenland Shelf Sediments

<p>The record of Icelandic volcanic events in Holocene marine sediments off SE Greenland provides evidence for the frequency and timing of atmospheric tephra plume dispersal from Iceland towards Greenland. Geochemistry of tephra abundance peaks from two SE Greenland shelf cores: MD99-2322 and JM96-1215-2GC are compared with core MD99-2269, north Iceland shelf, to evaluate the dispersal direction of Icelandic eruptions. Glass shard counts (106–1000 µm) in MD99-2322 revealed 16 distinct cryptotephra peaks. Geochemical analyses of eight cryptotephra peaks in MD99-2322 and two in JM96-1215 indicate sources in the volcanic systems of Iceland and Alaska. A tephra layer matching in geochemistry and stratigraphy to the <em>c.</em> 3600 BP eruption of the Aniakchak Volcano in the Aleutian Islands was identified in JM96-1215/2GC. The Settlement Tephra (AD 871±2) and Hekla B (H-B) were identified in MD99-2322. A new marker horizon, Katla EG-6.73, was found in both SE Greenland cores. Three basaltic peaks between 9.9 and 10.4 cal kyr BP, exhibit major-element geochemistry indistinguishable from the <em>c.</em> 10.2 kyr Saksunarvatn tephra. These layers represent 3 out of≥seven westward and northward-dispersed Grímsvötn layers found on the SE Greenland shelf and the north Iceland shelf between 9.9 and 10.4 cal kyr BP. </p

Nuclear_sequence_alignments

Non-partitioned multiple sequence alignments for various nuclear loci in FASTA format (.fasta)

MrBayes_inputs

Input nexus files (.nex) used for Bayesian phylogenetic inference for various datasets (mt=mitochondrial, nuc=nuclear, nt=standard coded (nucleotide), ry=ry-coded, m3=mitochondrial third codon positions, loops=mitochondrial rRNA loops

RaxML_inputs

Input phylip files (.phy) and partition files (_part.txt) used for maximum likelihood tree generation in RaxML for various data sets (mt=mitochondrial, nuc=nuclear, ry=ry-coded, m3=mitochondrial third codon positions, loops=mitochondrial rRNA loops). Note that RY coded bases are given by a 0 (R) or 1 (Y)

MCMCTree_inputs

Inputs in phylip format (.phy) for molecular dating analysis conducted in MCMCTree for several datasets (mt=mitochondrial, nuc=nuclear, nt=standard coded (nucleotide), ry=ry-coded, m3=mitochondrial third codon positions). Note that RY-coded data are represented by R and Y. Tree topologies (.trees) used as input are shown: for mitochondrial and combined mitochondrial/nuclear datasets, two topologies were tested, one in which moa/tinamous are sister to the remaining notopalaeognathae, and one where rheas are sister to the remaining notopalaeognathae. For the nuclear dataset, the topology derived from phylogenetic inference on the nuclear data alone was used. MCMCTree control files (.ctl) are not shown as parameters used are described in text

FASTQ

Total shotgun NGS (combined Ion Torrent Proton, Ion Torrent PGM, and MiSeq data as well as enriched and non-enriched libraries) reads (trimmed, quality filtered and unfiltered) in FASTQ format (.fastq)