Brief outline of the geology of New Caledonia - and the Southwest Pacific - Julien COLLOT (SGNC) - Ifremer
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Brief outline of the geology of New Caledonia
and the Southwest Pacific
Julien COLLOT (SGNC)
Martin PATRIAT (IFREMER)
Ifremer/JAMSTEC Workshop Subsea observatory in the South Pacific
Nouméa, 19 Septembre 2019
PNG SALOMON
Coral
Basin SAMOA
WF
North Fidji Lau
Zealandia
Basin FIDJI Basin
TONGA
NC
Lord Howe Hotspot
South Fidji
Tasmantid Hotspot
Basin Pacific
Ocean
AUSTRALIA
Tasman
Basin
NZ
La situation actuelle
Collot et al., EOS, 2012
PNG SALOMON
Coral
Basin SAMOA
WF
North Fidji Lau
Basin FIDJI Basin
TONGA
NC
Lord Howe Hotspot
South Fidji
Tasmantid Hotspot
Basin Pacific
Ocean
AUSTRALIA
Tasman
Basin
NZ
Geodynamic evolution
Bache et al., EPSL, 2012
NC
AUS
NZ
Gondwana
ANT
200‐100 Ma 100 Ma
100‐50 Ma 50 Ma
50‐0 Ma
Collot et al., Tectonics, 2008 Cluzel et al., Tectonophy., 2001
15‐0 Ma
Olivet & Aslanian, pers. Comm., 2000
Schellart et al., ESR., 2006
-6000 -5000 -4000 -3000 -2000 -1000 0
[m]
Carbonate platforms Oceanic crust
seafloor spreading
Obducted mantle
Abyssal depths
-7300 m
10
Hotspot Sedimentary basins Subduction zone / volcanic arcExceptional geodiversity
A few ideas for OBSERVATORIES
(not exhaustive !)
12Volcanism and hydrothermal systems
Patriat et al., G3, 2015
Patriat et al., EPSL, 2019
100 km
13Subduction/collision seismicity
2 subductions se faisant face !
2012-2019 seismicity
ORSNET network
Soulèvements des Loyautés
Dubois et al., JGR, 1974
Lebellegarde, pers comm, 2019Sea level rise and present day vertical land motions
Geodetic Vertical land motion measurements
Garcin & Lecozannet,
OBLIC annual report,
2017
Ballu et al., GJI, 2019
15Past-
vertical
motions
subsidence
and
uplift
Past sea-level
Cabioch, Sedimentary Geology,
162003
Sevin et al., GSL, in pressCoastal dynamics
Islet morphodynamics 2007 - 2014
Garcin et al., Cont. Shelf Res., 2016
Lagoonal hydrodynamics
Douillet, Zoneco Report, 2011 17Serpentinisation and weathering processes
impacts on mineral resources, energy and extreme life
CO2, H2O
H2
Carbonates
Peridotites
Carbonatation of peridotites
Hydrogen emanations
Ni, Co, Cr mineralisations
Archael and eubacterial communities
Aiguilles de Prony
Photo: IatokNew Caledonia Drilling Project
IODP : International Ocean Drilling Program
ICDP : International Continental Drilling Program
H2
Modified after Monnin et al., Biogeoscience, 2014 Patriat et al., Tectonics, 2018
Pre‐proposal 2020 www.newcaledoniadp.wordpress.com 19Abrupt margins and slope instabilities
Etienne et al., 2019
20
Collot et al., Tectonics, 2017Source to sink sediment transfers
Rouillard et al., Basin Research, 2017 Tournadour et al., Sedimentology, in rev
Solid vs dissolved transported particules Source to lagoon to deep basin
Carbonate vs siliciclastics Sedimentation rates, climate change, anthropisation 21MERCI !
Laurent, MSc thesis, 2011
2223
NCDP sites + prony + serpentinisation + H2 + carbonatation …
Stockage de CO2
Equation de carbonatation des peridotites
Olivine + CO2 ‐> Magnésite + Silice
et
Olivine + pyroxène + CO2 + H2O ‐> Serpentine + magnesite + calcite
Carbonatation sur résidus (ex: carboscorie) ou in‐situ (ex: Islande)
25Production d’hydrogène
Silicates FeMg + H2O ‐> Silicate FeMg hydraté + oxyde de fer + H2
Production d’énergie
Intérêt manifeste de plusieurs grands groupes (Total, Engie, GEO4U…)
26Peridotite Serpentinite
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