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Main facies
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Subfacies
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Facies
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Description
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Marine microfossils
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Lithostratigraphic unit
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Tentative depositional
environment/diagenesis
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Mud
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Massive mud with lonestones
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F1a
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(Dark) gray to (dark) greenish gray;
Facies thickness from 2.5 cm to 9.64 m
Varying amounts of lonestones from dispersed to abundant;
Mostly none to slight bioturbation, occasionally moderate to heavy bioturbation;
Occasional color banding and lamination;
Occasional occurrence of black mottles and silt/sand patches (<1 cm diameter);
Interbedded with Facies F1c, F1d, F2a, F2b, F3a, F4a, F4d, F5a, F5b, F5c, F6, and F7
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Rare diatoms
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I, IA, IIA, IIB, IIC, IID, III
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Suspension fall-out, ice rafting, or sediment gravity flows
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Massive mud without lonestones
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F1b
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(Dark) gray to (dark) greenish gray;
Facies thickness from 2 cm to 5.72 m
Mostly massive, occasional silt laminae;
Occasional color banding;
Rarely inclined;
Absent lonestones;
Mostly none to slight bioturbation, rarely moderate to heavy bioturbation;
Occasional occurrence of black mottles and silt/sand patches (<1 cm diameter);
Interbedded with Facies F1a, F1d, F2a, F2b, F3a, F4a, F4d, F5a, F5b, F5c, F6, F7, and F8
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Rare diatoms
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I, IA, IIA, IIB, IIC, IID, III
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Suspension fall-out or sediment gravity flows
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Laminated/Bedded mud
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F1c
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(Dark) gray to (dark) greenish gray;
Facies thickness from 5 mm to 4.85 m;
Mostly none to slight bioturbation;
Lamination resulting from slight color variations, presumably related to minor changes in grain size and/or geochemical variations
Lamination mostly from submillimeter to 0.5 cm, occasional very thin bedding (<2.5 cm) possible;
Mostly gradational contacts, very rarely sharp;
Rare lonestones;
Interbedded with Facies F1a, F1c, F2a, F2b, F3a, F5c, and F8
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Not documented
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IIB, IIC, IID, III
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Suspension fall-out, ice rafting, or sediment gravity flows
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Silt
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Silt
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F2a
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Gray to very dark gray;
Facies thickness from 2 mm to 7 cm;
Sharp to gradational upper and lower contacts;
Often normally graded;
Occasionally volcaniclastic bearing;
Separated from interbedded silt with mud because of relatively large bed thickness and interbedding with other facies than mud;
Interbedded with Facies F1a, F1c, F1d, F2b, F3a, F5a, F5b, and F7
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Not documented
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I, IIA, IID, III
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Sediment gravity flows
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Interbedded/Interlaminated silt and mud
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F2b
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Dark gray to very dark gray;
Facies thickness from 3 cm to 10.67 m;
Silt laminae interbedded in mud;
Most laminae <5 mm thick, up to 50 laminae per section;
Spacing from 2 mm to 17 cm;
Occasional color banding, dispersed lonestones are present;
None to slight bioturbation;
Most silt laminae with same color as matrix but sometimes lighter;
Mostly sharp lower contacts of the silt laminae, sharp to gradational upper contacts;
Occasionally calcareous, diatom, and volcaniclastic bearing;
Interbedded with Facies F1a, F1c, F1d, F2a, F3a, F4a, F5a, F5b, F6, F7, and F8
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Diatoms
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I, III
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Mud: suspension fall-out from surface water plumes and sediment gravity flows
Silt: sediment gravity flows
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Sand
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Very fine to coarse sand
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F3a
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Gray to very dark gray;
Mostly medium to (very) fine sand, occasionally muddy;
Very rarely coarse sand;
Mostly 1 to 11 cm thick, one 38 cm interval heavily disturbed (irregular occurrence of sand patches in mud);
Mostly normally graded;
Mostly erosive lower contacts;
Sharp and gradational upper contacts;
Often poorly sorted;
Occasionally with diatoms and volcanic ash;
Composition includes quartz, hornblende, and opaque grains;
Interbedded with Facies F1a, F1c, F1d, F2a,F2b, F5a, F5b, and F7
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Occasionally with diatoms
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I
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Sediment gravity flows
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Diamict
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Muddy diamict
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F4a
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Dark gray, very dark gray, and very dark greenish gray;
Muddy matrix, mostly clast poor, clasts up to pebble size;
Facies thickness from 2 cm to 14.35 m;
Mostly massive but occasionally some centimeter-thick intervals with (<5 mm) thick laminae;
Lower contacts either sharp or characterized by gradual increase in clast numbers;
Upper boundary either gradational or sharp due to drop in amounts of clasts;
Variations between intervals with higher and lower clast content within the facies
may occur;
Mostly not bioturbated, but intervals in lower parts of Hole U1418F are moderately bioturbated;
Some color banding may occur;
May very rarely contain volcaniclastic ash;
Clast types include quartz, feldspar, and biotite, as well as granitoid rocks, meta-sediment, black, red and white chert (partly with quartz veins), rhyolite, (black) siltstone, granodiorite to gabbro and basalt, and rip-up clasts of mud;
Interbedded with Facies F1a, F1c, F2b, and F7
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Not documented
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IIA, IIB, IIC, IID, III
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Suspension settling and ice rafting (icebergs and/or sea ice)
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Interbedded mud and diamict
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F4d
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Dark gray to very dark gray;
Facies thickness from 12 cm to 4.41 m
Lamination (in muddy intervals) and color banding to lighter gray possible;
None to slight bioturbation;
Diamicts mostly ~5 mm to ~4 cm thick, contain matrix of mud to very fine sand and mostly clasts of coarse sand to granules, rare clasts up to 2 cm, often associated with darker parts of color banding;
Gradational contacts between muddy and diamict intervals;
Interbedded with Facies F1a, F1c, F5b, and F7
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Not documented
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IIA, IIB
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Suspension settling and ice rafting (icebergs and/or sea ice)
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Diatom ooze
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F5a
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Dark greenish gray or very dark grayish brown;
Facies thickness from 3 cm to 2.91 m;
Sharp to gradational upper and lower contacts;
Occasionally with volcanic ash;
Mostly moderate to heavy bioturbation;
Lonestones are occasionally present and black mottles occur frequently;
Interbedded with Facies F1a, F1c, F2a, F2b, F3a, F5b, and F7
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Diatoms and other biosiliceous material (e.g., sponge spicules)
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I, IIB, IIC
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High-productivity environment and/or low terrigenous input and/or better preservation
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Biosiliceous ooze; biosiliceous-rich/bearing mud and sand; mud with diatoms/biosilica
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F5b
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Dark greenish gray;
Ooze or rich/bearing with diatoms, sponge spicules, foraminifers, nannofossils;
Facies thickness from 23 to 53 cm (ooze), 51 cm to 1.5 m (diatom rich), 40 cm to 4.5 m (diatom bearing), 20.5 cm to 2.62 m (mud with biosilica)
Slight to heavy bioturbation;
Few lonestones;
Often with volcanic ash;
Interbedded with Facies F1a, F1c, F2a, F2b, F3a, F4d, F5a, F5c, F7, and F8
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Diatoms, sponge spicules, foraminifers, nannofossils
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I, IIA, IIB, IIC
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Temporarily increased productivity and/or reduced suspension settling and/or better preservation
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Calcareous/ carbonate-bearing/rich mud
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F5c
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Gray, dark gray, very dark gray, dark greenish gray, and very dark greenish gray;
Facies thickness from 1 mm to 1.96 m;
Mostly slight to moderate but occasionally absent bioturbation;
Lonestones occasionally present;
Scattered foraminifer tests;
Occasionally in intervals with parallel lamination, tilted beds, or volcanic ash;
Gradational contacts;
Interbedded with Facies F1a, F1c, F1d, F5b, F7, and F8
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Foraminifers; occasionally diatoms
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I, IIB, III, IID
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Temporarily increased productivity and/or reduced suspension settling and/or better preservation
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Ash
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Volcanic ash
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F6
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Usually gray to brown;
Facies thickness from 1 to 5 cm;
Sharp lower contacts;
Sharp to gradational upper contacts;
Primarily vitric shards (glass);
Some intervals affected by moderate to heavy bioturbation, consequently, distinct ash layers are occasionally no longer visible, but the material is included in burrow fill;
Often interbedded with Facies F1a, F1c, F2b, and F7
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Not documented
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I, III
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Suspension settling after subaerial eruptions
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Volcaniclastic mud, sand, diamict, and/or ooze
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F7
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Gray, dark gray, very dark gray, and dark greenish gray;
Volcaniclastic-rich/bearing or trace amounts of volcanic ash;
Facies thickness from 5 mm to 5.58 m;
Mostly slight to moderate but occasionally absent bioturbation;
Lonestones present;
Occurrence in massive, color-banded, and laminated intervals;
Often in association with mud with higher amounts of biosiliceous and calcareous components;
Gradational and sharp contacts;
Interbedded with Facies F1a, F1c, F2a, F2b, F3a, F4a, F4d, F5a, F5b, F5c, and F6
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Biosiliceous and calcareous microfossils
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I, IIA, IIB, IIC, III
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Volcanic detritus either bioturbated or reworked/ redeposited by sediment gravity flows
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Rock
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F8
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Light to very dark gray siltstone and sandstone, most often with calcite cement;
Thickness from 1 to 6 cm, generally covering the entire core width, partly “flame structures” intruding into surrounding mud
Often interbedded with Facies F1c, F1d, F2b, F5b, and F5c
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Not documented
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III
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In situ carbonate cementation
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Intrastratal contorted mud and diamict
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F9
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Very dark greenish gray mud mixed with very dark greenish gray clast-rich muddy diamict;
Facies thickness is 7.79 m (limited to Cores 341-U1418F-70R through 72R);
Clasts include quartz, sandstone, metasediment, and greenstone;
Intrastratal contortion and normal faults occur;
Bioturbation is absent;
Only in contact with fall-in sandstone
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Not documented
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IV
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Sediment gravity flow
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