Site U1595 (proposed Site CSK-08B) is located in the southern basin of the Santorini caldera at 291 meters below sea level (mbsl) (Figure F1). It was drilled in three holes (U1595A–U1595C) to a maximum recovery depth of 127.0 meters below seafloor (mbsf) (all depths below seafloor are given using the core depth below seafloor, Method A [CSF-A], scale, except in Operations where the drilling depth below seafloor [DSF] scale is used). Average hole core recoveries range 46%–77%. Site U1594 addresses the same drilling objectives and lies northeast of Site U1595. Two additional sites (U1596 and U1597) lie in the northern caldera basin.
Four seismic units (S1–S4) were previously recognized in the Santorini caldera (Johnston et al., 2015; Nomikou et al., 2016) (Figure F2). Seismic Units S1–S3 were thought to consist of muds and sands from cliff mass wasting (Unit S1); compacted (possibly lithified) sandy volcaniclastics from Kameni Volcano (Unit S2); and consolidated coarse blocky intracaldera tuffs, landslide debris, and/or flood gravels (Unit S3). Unit S4 was thought to be intracaldera tuff from the Late Bronze Age eruption. The four caldera sites were planned to sample Units S1–S3; test the published correlations between the two caldera basins; penetrate below Unit S3 into Unit S4; and address scientific Objectives 1, 4, 5, and 7 of the Expedition 398 Scientific Prospectus (Druitt et al., 2022). By drilling both caldera basins and exploiting our dense seismic reflection coverage, we gained access to the 3D architecture of the entire caldera fill. We also targeted the question of why the northern basin is 100 m deeper than the southern one. Finally, we tested whether Unit S3 consisted of flood debris from the caldera flooding event (Nomikou et al., 2016) or whether it was Late Bronze Age intracaldera tuff (Johnston et al., 2015). The intracaldera sites were used for microbiological work of Objective 7.
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This content will become publicly available on July 30, 2025
Site U1594
Site U1594 (proposed Site CSK-07B) is located in the southern basin of Santorini caldera at a water depth of 291 meters below sea level (mbsl) (Figure F1). It was drilled to a maximum recovery depth of 50.1 meters below seafloor (mbsf) in a single hole (U1594A) with 93% recovery before hole instability set in and the hole was terminated (all depths below seafloor are given using the core depth below seafloor, Method A [CSF-A] scale, except in Operations where the drilling depth below seafloor [DSF] scale is used). Site U1595 addresses the same drilling objectives and lies southwest of Site U1594. Two additional sites (U1596 and U1597) lie in the northern caldera basin.
Four seismic units have been recognized in the caldera (Johnston et al., 2015; Nomikou et al., 2016) (Figure F2). They were thought to consist of muds and sands from cliff mass wasting (Seismic Unit S1); compacted (possibly lithified) sandy volcaniclastics from Kameni Volcano (Unit S2); and consolidated coarse blocky intracaldera tuffs, landslide debris, and/or flood gravels (Unit S3). Unit S4 was thought to be intracaldera tuff from the Late Bronze Age eruption. The four caldera sites were planned to sample Units S1–S3; test the published correlations between the two caldera basins; penetrate below Unit S3 into Unit S4; and address scientific Objectives 1, 4, 5, and 7 of the Expedition 398 Scientific Prospectus (Druitt et al., 2022). By drilling both caldera basins and exploiting our dense seismic reflection coverage, we gained access to the 3D architecture of the entire caldera fill. We also targeted the question of why the northern basin is 100 m deeper than the southern one. Finally, we tested whether Unit S3 consisted of flood debris from the caldera flooding event (Nomikou et al., 2016) or was Late Bronze Age intracaldera tuff (Johnston et al., 2015). The intracaldera sites were used for microbiological work of scientific Objective 7.
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- Award ID(s):
- 1326927
- PAR ID:
- 10528195
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- International Ocean Discovery Program
- Date Published:
- Journal Name:
- Proceedings of the International Ocean Discovery Program Expedition reports
- Volume:
- 398
- Issue:
- 108
- ISSN:
- 2377-3189
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Site U1596 (proposed Site CSK-06B) is located in the northern basin of the Santorini caldera (Figure F1). It lies at 382 meters below sea level (mbsl) and has a maximum recovery depth in two holes (U1596A and U1596B) of 40.6 meters below seafloor (mbsf) with 87%–91% core recovery (all depths below seafloor are given using the core depth below seafloor, Method A [CSF-A], scale, except in Operations where the drilling depth below seafloor [DSF] scale is used). Site U1597 addresses the same drilling objectives and lies southeast of Site U1596. Two additional sites (U1594 and U1595) lie in the southern caldera basin. Four seismic units were previously recognized in the Santorini caldera (Johnston et al., 2015; Nomikou et al., 2016) (Figure F2). They were thought to consist of muds and sands from cliff mass wasting (Unit S1); compacted (possibly lithified) sandy volcaniclastics from Kameni Volcano (Unit S2); and consolidated coarse blocky intracaldera tuffs, landslide debris, and/or flood gravels (Unit S3). Unit S4 was thought to be intracaldera tuff from the Late Bronze Age eruption. The four caldera sites were planned to sample Units S1–S3; test the published correlations between the two caldera basins; penetrate below Unit S3 into Unit S4; and address scientific Objectives 1, 4, 5, and 7 of the Expedition 398 Scientific Prospectus (Druitt et al., 2022). By drilling both caldera basins and exploiting our dense seismic reflection coverage, we gained access to the 3D architecture of the entire caldera fill. We also targeted the question of why the northern basin is 100 m deeper than the southern one. Finally, we tested whether Unit S3 consisted of flood debris from the caldera-flooding event (Nomikou et al., 2016) or whether it was Late Bronze Age intracaldera tuff (Johnston et al., 2015). The intracaldera sites were used for microbiological work of Objective 7.more » « less
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Site U1597 (proposed Site CSK-05C) is located in the northern basin of the Santorini caldera (Figure F1). It lies at a water depth of 382 meters below sea level (mbsl) and has a maximum recovery depth of 42.7 meters below seafloor (mbsf) (all depths below seafloor are given using the core depth below seafloor, Method A [CSF-A], scale, except in Operations where the drilling depth below seafloor [DSF] scale is used) with 94% core recovery. Site U1597 addresses the same drilling objectives and lies southeast of Site U1596. Two additional sites (U1594 and U1595) lie in the southern caldera basin. Four seismic units have been recognized in the Santorini caldera (Johnston et al., 2015; Nomikou et al., 2016) (Figure F2). They were thought to consist of muds and sands from cliff mass wasting (Unit S1); compacted (possibly lithified) sandy volcaniclastics from Kameni Volcano (Unit S2); and consolidated coarse blocky intracaldera tuffs, landslide debris, and/or flood gravels (Unit S3). Seismic Unit S4 was thought to be intracaldera tuff from the Late Bronze Age eruption. The four caldera sites were planned to sample Units S1–S3; test the published correlations between the two caldera basins; penetrate below Unit S3 into Unit S4; and address scientific Objectives 1, 4, 5, and 7 of the Expedition 398 Scientific Prospectus (Druitt et al., 2022). By drilling both caldera basins and exploiting our dense seismic reflection coverage, we gained access to the 3D architecture of the entire caldera fill. We also addressed the question of why the northern basin is 100 m deeper than the southern one, with a thicker Unit S1 but a thinner Unit S3. Finally, we tested whether Unit S3 consisted of flood debris from the caldera-flooding event (Nomikou et al., 2016) or whether it was Late Bronze Age intracaldera tuff (Johnston et al., 2015). The intracaldera sites were used for microbiological work of Objective 7.more » « less
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