Summary of Physical and Chemical Characteristics
of the Focus Arc-Trench Systems
This is an evolving compilation/worksheet; those wishing to add or correct information should contact the Editors for this section Gray Bebout and Tim Elliott.
Sources of Data:
Jarrard (1986); von Huene and Scholl (1991, 1996); Kirby et al. (1991, 1996); Plank and Langmuir (1998).
| Arc-Trench System |
Convergence Rate (mm/year) |
Age of Subducting Oceanic Lithosphere (Ma) |
Thermal Parameter (Phi)** |
Sediment Thickness (m) |
Sediment Type(s) |
Sediment Confidence Level (1-5)† |
| Izu-Bonin-Mariana (IBM) | ||||||
| Izu-Bonin | 50 | 135 | ~600 | drilling planned 1999 | 4 | |
| Mariana | 47.5 | 165 | 400-500 | pelagic brown clay, chert and porcellanite ± limestone volcaniclastic turbidites | 1 | |
| Central America (w/Mexico) | ||||||
| Central America | 77 (70-90) |
22-23> | 425 | hemipelagic, diatome-rich mud, pelagic carbonate | 1 | |
| Mexico | 52 | 15 | 200 | hemipelagic muddy silt, brown pelagic clay | ||
| Tonga | ||||||
| Tonga | 164-240 | 120 ± 20 | <100 | pelagic brown clay, chert, porcellanite (Site 595/596) | 1 | |
| Aleutians | ||||||
| Aleutians | 62 | 54 (50-65) | 350 | diatom ooze, greenish gray clay, silty clay | 1 | |
| Cascadia | ||||||
| Cascadia | 35 | 8 | 1500 | volcaniclastic fan deposits and more distal turbidites | 4 | |
| Banda | ||||||
| Banda | 67 | ~160 | 500-900 | carbonate turbidites clay, radiolarian clay | 1 | |
| Lesser Antilles | ||||||
| N. Antilles | 24 | 68 | 200- 1000's | ashy mud, radiolite clay, zeolite clay, and calc, ferruginous claystone | 2 | |
| S. Antilles | 24 | 68 | 1750 | |||
| Andes | ||||||
| Peru | 100 | 45 | 125 | clay, brown pelagic clay (Site 321) silicic green clay, nanno ooze | 3 | |
| North Chile | 100 | 82 | ? | 5 | ||
| Central Chile | 98 | 48 | ? | 5 | ||
| South Chile | 97 | 40-5 | ? | 5 | ||
**Thermal parameter from Kirby et al. (1991, 1996). Phi = (age of subducting lithosphere) x (vertical descent rate).
†Sediment confidence levels from Fig. 14 of Plank and Langmuir (1998).