Table T3. Summary of stratigraphic units at Site 1173 and correlation with equivalent units at Site 808 (from Shipboard Scientific Party, 1991).

Unit Sub-unit Facies name Interval (cm)   Depth (mbsf)
Thickness (m) Stratigraphic
age		 Lithologic
description		 Processes
of formation		 Tectonic and
physiographic
setting		 Stratigraphic
correlation with Site 808
Top
Bottom
Top
Bottom



190-1173A- 190-1173A-









I IA Outer-trench wedge 1H-1, 0 10H-1, 23
0.00 83.37
83.37 Quaternary Silty clay, sand, silt, and rare volcanic ash Turbidity currents, hemipelagic settling, rare settling of ash Outer-trench wedge Units IIB, IIC

IB Trench to basin transition 10H-1, 23 12H-1, 0
83.37 102.14
18.77 Quaternary Silty clay, abundant volcanic ash, rare thin silt Hemipelagic settling, settling of ash, rare turbidity currents Trench to basin transition Unit III
II
Upper Shikoku Basin 12H-1, 0 37X-3, 3
102.14 343.77
241.63 Pliocene to Quaternary Silty clay, abundant volcanic ash Hemipelagic settling and frequent settling of volcanic ash Shikoku Basin closer to trench; volcanism in Kyushu/Honshu Unit IVA
III
Lower Shikoku Basin 37X-3, 3 73X-2, 15
343.77 687.99
344.22 middle Miocene to early Pliocene Silty claystone, calcareous claystone, siliceous claystone Hemipelagic settling, rare settling of ash, and diagenetic alteration Shikoku Basin distal from trench Unit IVB
IV
Volcaniclastic 73X-2, 15 77X-CC, 25
687.99 724.89
36.90 Probable middle Miocene Siliceous claystone, silty claystone Acidic volcanism, hemipelagic settling, and diagenetic alteration Japan Outer Zone volcanism - triggered by ridge subduction Unit V
V
Basalt basement 77X-CC, 25 77X-CC, 26
724.89 724.90
0.01 Probable middle Miocene Basalt Formation of igneous crust at spreading ridge Oceanic basement of Shikoku Basin Unit VI