Table 2 Summary of sedimentological, paleontological, and geochemical analysis of the event sand layers (S1 to S10)
Sand unit | Grain size analysis | Computed tomography | Paleontological indicators: marine diatom species/shell fragments | Carbonate content | Magnetic susceptibility | Micro X-ray fluorescence by ITRAX (description for the main core—H02) | X-ray diffraction | Modeled depositional age (2σ) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Grading | Sorting vertical change | Thickness change | Basal contact | Flow structures | Lateral change | Titanium | Rubidium | Ca/Ta (clastic/mud ratio) | Glauconite | ||||
S1 | Massive | No change | Not continuous | Bioturbated | Not visible | – | – | – | No change | Peak | Low-peak | – | 1239–1924 cal BP |
S2 | Massive | No change | Not continuous | Bioturbated | Not visible | – | – | – | No change | Peak | High-Peak | – | 1935–2774 cal BP |
S3 | Massive | No change | Not continuous | Bioturbated | Not visible | – | – | – | No change | Peak | Low-peak | – | 1935–2774 cal BP |
S4 | Massive | Upward increase | Landward thinning | Bioturbated | Not visible | – | 0.1% | Landward decrease | Constant | Constant | High-flat | Yes | 2769–3068 cal BP |
S5 | Upward fining (skewness variation and phi mode change) | Upward sorting decrease—presence of coarse pumice towards the top | Landward thinning | Erosive | Not visible | 1 specie (Fallacia sp.)/shell fragment (Fig. 11) | 0.2% | Landward decrease | Upward reduction | Upward increase | High-upward reduction | Yes | 3020–3499 cal BP |
S6 | Constant | No change | Landward thinning | Planar contact | Not visible | Not recorded | 0% | Landward decrease | Constant | Peak | Low-constant | Yes | 3469–3859 cal BP |
S7 | Upward coarsening at H02 | Upward increase | Landward thinning | Bioturbated | Not visible | 3 species (Adoneis sp.; Fallacia sp.; Melosira moniliformis) | 0% | Landward increase—decrease | Slightly upward increase | Upward decrease | Moderate-upward increase | Yes | 3823–4362 cal BP |
S8 | Upward coarsening—massive—upward fining in H02 Upward finning in H03 and H04 | Upward increase—upward decrease (inclusion of coarse and rounded grains of pumice) | Landward thinning | Erosive.Erosive surface bounding the two subunits | Rip-up clast at the base | 4 species (Adoneis sp.; Delphineis sp.; Diploneis smithii; Melosira moniliformis) | 0% | Landward decrease | Upward increase—upward reduction | Lower unit: upward decrease Upper unit: constant | Low peak in the base, rapid increase, constant in the middle part and upward fining in the last 1/3 | Yes | 4286–4784 cal BP |
S9 | Massive | No change | Landward thickening and thinning | Erosive. Erosive surface bounding the two subunits | Rip-up clast in the interbedding mud-layer, flame structure | 1 specie (Adoneis sp.) | 0.1% | Not significant change | Upward reduction in two pulses | Peak | Low in the base, moderate in the upper part | No | 4677–5012 cal BP |
S10 | Upward fining in the distal core sample (H04) | No change | Landward thinning | Erosive | Not visible | 2 species (Adoneis sp.; Melosira moniliformis) | 0.3% | Landward decrease | Upward reduction, increase and constant | Upward increase | High—Upward reduction | Yes | 4942–5522 cal BP |