Draut, Amy E. and Clift, Peter D. (2006): Sedimentary processes in modern and ancient oceanic arc settings; evidence from the Jurassic Talkeetna Formation of Alaska and the Mariana and Tonga arcs, Western Pacific

Leg/Site/Hole:
ODP 135
ODP 135 840
ODP 135 841
Identifier:
2006-056461
georefid

10.2110/jsr.2006.044
doi

Creator:
Draut, Amy E.
University of California at Santa Cruz, Santa Cruz, CA, United States
author

Clift, Peter D.
University of Aberdeen, United Kingdom
author

Identification:
Sedimentary processes in modern and ancient oceanic arc settings; evidence from the Jurassic Talkeetna Formation of Alaska and the Mariana and Tonga arcs, Western Pacific
2006
Journal of Sedimentary Research
Society for Sedimentary Geology, Tulsa, OK, United States
76
3-4
493-514
Sediment deposited around oceanic volcanic areas potentially provides the most complete record of the tectonic and geochemical evolution of active margins. The use of such tectonic and geochemical records requires an accurate understanding of sedimentary dynamics in an arc setting: processes of deposition and reworking that affect the degree to which sediments represent the contemporaneous volcanism at the time of their deposition. We review evidence from the modern Mariana and Tonga arcs and the ancient arc crustal section in the Lower Jurassic Talkeetna Formation of south-central Alaska, and introduce new data from the Mariana Arc, to produce a conceptual model of volcaniclastic sedimentation processes in oceanic arc settings. All three arcs are interpreted to have formed in tectonically erosive margin settings, resulting in long-term extension and subsidence. Debris aprons composed of turbidites and debris flow deposits occur in the immediate vicinity of arc volcanoes, forming relatively continuous mass-wasted volcaniclastic records in abundant accommodation space. There is little erosion or reworking of old volcanic materials near the arc volcanic front. Tectonically generated topography in the forearc effectively blocks sediment flow from the volcanic front to the trench; although some canyons deliver sediment to the trench slope, most volcaniclastic sedimentation is limited to the area immediately around volcanic centers. Arc sedimentary sections in erosive plate margins can provide comprehensive records of volcanism and tectonism spanning <10 My. The chemical evolution of a limited section of an oceanic arc may be best reconstructed from sediments of the debris aprons for intervals up to approximately 20 My but no longer, because subduction erosion causes migration of the forearc basin crust and its sedimentary cover toward the trench, where there is little volcaniclastic sedimentation and where older sediments are dissected and reworked along the trench slope.
English
Serial
Coverage:Geographic coordinates:
North:62.1500
West:-175.4456East: -147.0000
South:-22.1316

Sedimentary petrology; Alaska; breccia; clastic rocks; Copper River basin; igneous rocks; Jurassic; Leg 135; Lower Jurassic; Mariana Islands; Mariana Trough; marine sedimentation; Matanuska Valley; Mesozoic; Micronesia; North Pacific; Northwest Pacific; Ocean Drilling Program; Oceania; ODP Site 840; ODP Site 841; Pacific Ocean; Polynesia; processes; pyroclastics; sedimentary rocks; sedimentation; Southern Alaska; submarine volcanoes; Talkeetna Formation; Tonga; tuff; United States; volcanic breccia; volcanic rocks; volcaniclastics; volcanoes; West Pacific;

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