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Arc systems play an important role in the elemental budget of the
oceans derived from the lithophere (upper mantle, ocean crust and
sediment coverage) and they have become increasingly recognized as
potential resources of metals. Active seafloor hydrothermal systems
pump acidic and extremely metal-rich high temperature fluids into
the ocean that leads to the formation of one of the most extreme
environments of life on earth.
An exceptional example to study an active Au-Co-Ag-rich
hydrothermal system is the Brothers volcanic center, southern
Kermadec arc, located ~400 km north of New Zealand within New
Zealand’s extended economic zone (EEZ).
With a total length of 22,000 km and typically several hydrothermal
vent sites per 100 km, volcanic arcs are as equally important as mid
ocean ridges in overall hydrothermal mass transfer from the
lithosphere to the mantle. In addition, high concentrations of S
species gases, CO 2 and metals can potentially lead to the formation
of ore deposits of different style/type to those discovered along
mid ocean ridges and be host to unknown microbes. The difference
in the style and type of hydrothermal mineralization along arcs is
essentially a result of the different composition and volatile-rich
nature of the host lava, which contributes magmatic vapors
(including metals) through magma degassing in shallow magma
reservoirs to the expelled fluids.
Recent investigations of arc hydrothermal vents have provided the
first insights into varied magma-hydrothermal-biological feedback
within the systems, but little is known about subseafloor
mineralization and microbial habitats. Furthermore, knowledge on
the potential to form subseafloor ore deposits on hydrothermally
active volcanoes is entirely lacking.
Drilling of the hydrothermal system of Brothers volcano would
provide missing information about the potential to form subseafloor
mineral deposits and will give new insights into unknown microbial
environments at these volcanoes.
Philippines
Graciano P Yumul, Jr. and Dr. C.B. Dimalanta
The Philippine report is by means of a paper, published in the International Research section of this volume.
Portugal
Pedro Ferreira and Ricardo Santos
From mid-August to mid-October 2012, the Task Group for the
Extension of the Continental Shelf (EMEPC) conducted an
oceanographic cruise aboard the Portuguese Navy Vessel NRP
Almirante Gago Coutinho, to the mid-Atlantic ridge axis and off-axis
area located between the Oceanographer and Hayes fracture zones.
As in previous missions led by the EMEPC, the cruise was
The following are current projects:
characterized by a multidisciplinary approach under the scope of
the extension of the Portugal's continental shelf program. A team
of geology, macro and microbiology, oceanography and geophysics
researchers from several national institutes and universities were onboard
to work in-situ with samples and data collected by the Luso, a
6000 m-rated ROV.
Funded by Portuguese National Science Foundation:
Project Title PI Start Date Duration
DEEPFUN - Biodiversity and functioning of the deep-sea
hydrothermal field Menez Gwen- a contribution to management
policies.
CARCACE - Colonization of mAmmal caRCasses in the deep
Atlantic ocEan
TerRiftic project - unraveling melting processes and volcanism on
the Terceira Rift, Azores: a melting inclusion study.
Ana Colaço (IMAR-
DOP/UAç)
01-04-2011 36 months
Ana Hilario- Cesam
(IMAR-DOP/UAç partner)
01-06-2010 36 months
Filipa Marques- 01-03-2011 36 months
CREMINER
INTERRIDGE NEWS 43 VOL.21, 2012