HG 198.20-198.35 Thin Section

Coarse grained brown sediment with angular-sub-angular grains. Contains mainly medium sized clasts with a few smaller aggregates. A dark organic rich domain can be seen within this sample. Grain crushing (edge-to-edge and into one another) can be seen alongside with grain stacks, and silt caps.

HG 290.45-290.55 Thin Section

Two main domains can be seen in this sample. One is coarse grained with clasts ranging from small to medium in size. The other is very fine grained, and a very dark brown, potentially influenced by organic material. Grain crushing and lineations can be seen in the coarser domain.

HG 177.35-177.45

Dark brown sediment with organic matter. There are two main domains; a coarse grained domain, and a finer grained domain. The coarse grained domain contains grains ranging from small to medium in size, and angular to sub-rounded in shape. In the coarse grained domain, grain crushing/stacking is common, with a few lineations and rotation structures. In the finer grained domain, grains are small and range from sub-angular to sub-rounded in shape. Lineations are abundant in this domain.

Sediment organic matter, grain size, and results of prediction models from northern North Atlantic and Arctic Seas

Sediment samples and hydrographic conditions were studied at 28 stations around Iceland. At these sites, Conductivity-Temperature-Depth (CTD) casts were conducted to collect hydrographic data and multicorer casts were conductd to collect data on sediment characteristics including grain size distribution, carbon and nitrogen concentration, and chloroplastic pigment concentration. A total of 14 environmental predictors were used to model sediment characteristics around Iceland on regional geographic space. For these, two approaches were used: Multivariate Adaptation Regression Splines (MARS) and randomForest regression models. RandomForest outperformed MARS in predicting grain size distribution. MARS models had a greater tendency to over- and underpredict sediment values in areas outside the environmental envelope defined by the training dataset. We provide first GIS layers on sediment characteristics around Iceland, that can be used as predictors in future models. Although models performed well, more samples, especially from the shelf areas, will be needed to improve the models in future.

HG 482.15-482.35

Brown sediment with a coarse grained domain and a few finer grained domains throughout the sample. Clasts range from small to large in size and angular to sub-rounded in shape. In the coarser domain, grain crushing is common. A few rotation structures can also be seen throughout the sample, along with lineations.

PBURWELL #1-87

This sample contains two main domains. One is a light brown sediment domain with mainly small clasts which are clustered together. Only a few larger clasts can be seen in this domain. The other one is dark brown with well dispersed clasts. The light brown domain contains clasts that range from sub-angular to sub-rounded in shape. Lineations can be commonly seen in this domain. Grain crushing is also common with minor amounts of rotation. In the dark brown domain, clasts range from small to medium in size. They range from sub-angular to sub-rounded in shape. A few lineations and rotation structures can be seen in this domain.

HG 196.20-196.30 Thin Section

Brown, coarse grained sediment , with clay material. Clasts range from small to large, and sub-angular to sub-rounded. Organic material can be seen. Lineations are abundant. Grain stacking edge-to-edge grain crushing can also be seen. Organic material can be seen. Edge-to-edge grain crushing is seen throughout the image. Contains the inclusion of a finer domain.

HG 206.85-206.95 Thin Section

Coarse grained sample with sub-angular to sub-rounded clasts. Clasts range from small to medium sized. Major grain crushing seen throughout the sample. Grain stacking and lineations are also present. A dark organic rich domain can be seen within the sample.

HG 215.65-215.75 Thin Section

Brown to dark brown sediment with small to medium sized clasts ranging from sub-angular to sub-rounded. This sample contains a coarse grained domain and a fine grained domain. Clear boundaries can be seen. Grain stacking can be seen in the coarse domain, while lineations are the dominant microstructure in the fine grained domain. Minor grain crushing can also be seen. Some of the coarser domain is rich in clay and organics.

HG 129.65-129.75

Brown sediment with two main domains; a fine grained one rich in organic material and a coarse grained domain. The fine grained domain appears in several areas of the sample, and in one area alternates with the coarser domain. The coarse grained domain contains clasts ranging from small to medium in size, and angular to sub-rounded in shape. Grain crushing and lineations can commonly be seen in this domain.

HG 186.9-187.0 D.E.

Coarse grained sediment with a few fine grained matrices. Brown sediment with small to medium sized clasts. Clasts range from sub-angular to sub-rounded. Organic material present. It contains rotation structures throughout as well as edge-to-edge grain crushing. Fine grained clay domains are present and lineations can also be seen. Minor amounts of grain stacking can also be seen.

HG 225.15-225.25 Thin Section

Dark brown sediment with sub-angular to sub-rounded grains, that range from small to medium in size. Lineations with fractured grains are abundant, and grain crushing can also be seen. Minor rotation can also be seen.

HG 257.55-257.75 Thin Section

Dark brown sediment with clasts that range from small to large. The clast shape ranges from sub-angular to sub-rounded. Lineations are abundant in this sample. Edge-to-edge grain crushing can also be seen. Darker organic rich domains are also present throughout the sample.

HG 305.15-305.30

Dark grey sediment with medium to small sized grains. The grains are sub-angular in shape. Rotation structures and grain crushing are the most common microstructures seen. Dark organic material and lineations can also be seen.

384.85-385.0 DE # 11

Mainly coarse grained with a separate fine grained clay domain occurring throughout the sample. The coarse grained domain contains clasts that range from small to medium in size. The clast shape ranges from angular to sub-angular. Grain crushing is abundant in this sample, along with lineations, and minor amounts of rotation.