Volatile Recycling at Subduction Zones Terry Plank, Lamont Doherty Earth Observatory The Subduction Factory

Is the Ocean Shrinking?

60% of structurally- bound H 2 O released Hacker (2008) G3; Jarrard (2003) G3 Water Fluxes During Subduction

60% of structurally- bound H 2 O released Hacker (2008) G3 Water Fluxes During SubductionH 2 O Output? H 2 O % in magma Magma Mass Flux

Centam H 2 O (least degassed) wt% Arc Data: 2000 MORBMORB (SubFac Science Plan)

Aleutians Centam Marianas Mexico Tonga Kamchatka H 2 O (least degassed) wt% Arc Data: 2009 MORBMORB 3.9 wt% H 2 O +/- 1.0 (1 stdev)

Average Arc Growth Rates Suyehiro et al. (1996) Science Holbrook et al (1999) Geology ( km 3 /km/Ma) Izu Arc Aleutian Arc (Reymer&Schubert, 1984) (Holbrook et al., 1999) (Dimalanta et al., 2002) (Jicha et al., 2006) Duration: 46 Ma 28 (Reymer&Schubert, 1984) 66 (Suyehiro et al., 1996) (Dimalanta et al., 2002) Duration: 47 Ma

Th input (g/yr) Th output (g/yr) = C Th * Magma Mass Flux Hebert et al (2009) 100 km

60% of structurally- bound H 2 O released Hacker (2008) G3 Water Fluxes During Subduction4 +/- 1 wt% H 2 O arcs 60 +/- 20 km 3 /km/Ma 3.0E8 = 40 +/- 20 % recycled to arc

Millions of years before present Relative sea level change (meters) 70% 40% 50% Subduction of Water Lowering Sea Level 50% water recycled to surface from Rupke et al. (2004)

Millions of years before Present Global Sea Level Variations meters Hallam (1982); and Wallman (2001) Sea level fall over past ~ 600 Ma due to subduction of water??

from Rupke et al, Earth and Planetary Science Letters (2004) Size of Ocean today Ocean growing Ocean shrinking hotter mantle cooler mantle

2% H 2 O in 4 km mantle 5.7

All serpentine- bound H 2 O bypasses arc? Hacker (2008) G3 Water Fluxes During Subduction

2% H 2 O in 4 km mantle 5.7 past arc Lose ocean In 1.7 Ga!

Wiens/Lizarralde MARGINS experiment

Subducting Carbonate and CO 2 Cycling

GLOSS - global subducting sediment Plank & Langmuir (1998) Centam Plank, et al (2002) Geology

Altered oceanic crust Alt figure?? (1999) GCA

CO 2 Output?? Figure from Wallace (2005) JVGR

Melt Inclusions - minimum CO 2 ? Benjamin et al. (2007) JVGR -- Irazu Volcano, Costa Rica

Global Flux Estimates from Wallace (2005) JVGR

C Flux in & out of the mantle (Alt & Teagle, 1999; Sleep & Zahnle, 2001; Jarrard, 2003) Courtesy of M. Hirschmann Input Output 25%

Centam, CO 2 flux from slab Gorman et al (2006) G3

Shaw et al (2003) EPSL Typical CO 2 / 3 He in Centam despite major carbonate subduction

H 2 O Recycling REE/Th CO 2 Recycling 40-60% returned to arc serpentine subduction? 25% returned to arc decarbonation? CO 2 fluxes out volcanoes