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Table 2 Description and interpretation of event lithotypes including photo of core section (origin of line scan is indicated in the lower right corner of core photos, scale is in cm). Yellow double arrows indicate the vertical extent of described event layer

From: Postglacial evolution of Lake Constance: sedimentological and geochemical evidence from a deep-basin sediment core

Event lithotypes

Description

Interpretation

Core photo

LE1: mm-scaled coarser oxidized sandy layers and patches. These layers occur at the base of fining upwards event layers or isolated

Rusty colour indicates high concentration of iron-sulphide minerals. Minerals may be of allocthonous origin (event deposits) or more likely of post depositional origin, in particular in the isolated finer layers and patches. Not clear, if oxidation was pre- or post-drilling

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LE2: fining upwards brown to grey-brown layers at cm-scale with occasional wavy structures and slight brightening towards top. Sometimes base with initial coarsening-upward trend. Layers with gentle erosive basal contact. One prominent layer (8.9–9.02 mcd) reaches a thickness of ~ 10 cm. Maximum grain size reaches up to middle sand in the thickest layer, otherwise silt to maximal fine sand

Turbiditic event deposit, thickness variation due to the intensity and distance to the event. Lack of coarser grains at the base hints to a more distal source. The colour indicates an allochthonous source rather than remobilised lake deposits. The waving and graded internal structure hints towards a slow-event deposition under rarely increasing and the decreasing energy condition, typical for flood events

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LE3: grey to dark grey silt layers at a mm to cm-scale. Homogeneous darker lower part, with a fining upwards and brightening-up top part. With a partly erosive basal contact

Turbiditic event deposit, variation in thickness is related to the size and distance to the event. Lack of coarser fractions at the base hints towards a distal source. The mostly homogeneous structure and bright clay caps indicate a fast deposition, typical for mass movement deposits, and therefore mainly remobilised lake-sediments

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LE4: structureless bright yellowish-beige clay layers in a mm- to cm-scale

Interpreted as aeolian transported loess deposits, colour change may indicate a difference origin of the loess or a higher concentration then in LB7 (Niessen et al., 1992; Wessels, 1995, 1998a, 1998b, 1998c)

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LE5: mud-clast conglomerate: mixture/melange of beige fine- to middle-sand, with beige silty mud-, yellowish-beige clay-, and grey clay-clasts. With an average CaCO3-content of ~ 30%

Mass movement deposit formed in subaquatic channel

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LE6: Fining-upward dark grey to brownish fine- to occasionally middle-sand sequence. Thickness of individual sequences in a mm- to dm-scale. Occasionally, high concentration of terrestrial organic material and/or a high mica concentration in the fine fraction. Average CaCO3-content (15–20%)

Distal subaquatic channel deposits, the fining upward sand sequences represent the active states of the channel. The thickness of the sand-sequences is controlled by the size and the distance of the event. The terrestrial material in the sand sequences indicates at least partly terrestrial sand source. Deposited in deep water and medium- to high-energy conditions

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LE7: massive unstructured dark grey to brownish middle- to coarse-sand. Thickness of individual layers range from dm- to m-scale. Average CaCO3-content (15–20%)

Proximal main subaquatic channel deposits, each graded sequence represents a single event. Deposited under deep-water and high energy conditions

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