Page 630 - Economia Azul - versão: inglês

Figure 1y (A) Location map showing the gons show the location of plumes, whi- From the seafloor mapping, several gas hydrates is dispersed nodules in the
position of the Foz do Amazonas Fan le green stars represent locations where submarine mounds were identified with mud matrix, massive layers 10 cm thick have
(red line) and the multibeam echo soun- piston gas hydrates (piston colors) were relief between 10-20 m in height, in water also been recovered (KETZER et al., 2018).
der survey area (black polygon), red dots recovered. The black line C–C’ indicates depths of 1000-1800 m (Figure 3y). These
indicate locations drilled during ODP 155 the position of the seismic line at C. (C) features are located near the edge of the Figure 3y: Seafloor images generated
from a multibeam echo sounder survey,
(PIPER et al., 1997). The -600 m isobath SW-NE seismic profile cutting the NW-SE gas hydrate stability zone and associated illustrating zones of seafloor fluid leaks
line (in red) represents the approximate direction structures and a detail showing with faults; in one of them the gas hy- associated with gas plumes in the water
depth of the edge of the methane hydra- the BSR reflector (yellow line) and detail drate samples were recovered. Deep-sea column: (A) Plumes aligned NW- SE illus-
te stability zone in the area. (B) Detail of of the deep faults that reach the detach- trating the variation in height according
the multibeam survey area: black hexa- ment surface (red line). mounds are often associated with gas to the increase in water depth; the red
seeps (plumes) recognized in the water
Studies on the occur- column (KETZER et al., 2018, 2019). Seeps dashed line corresponds to the C-C’ seis-
mic line (Figure 1y);
rence of gas hydrates gained located near the edge of the gas hydrate (B) Set of aligned plumes, associated with
greater interest from 2010 stability zone may be linked to hydrate dis- the upper limit GHSZ (dashed yellow
onwards, with the launch sociation related to contemporary ocean line), isobath ~600m, note the presence
of the Tucuxi project in the warming (KETZER et al., 2019). Although of submarine mounds (arrows).
Foz do Amazonas Basin. This the most common form of occurrence of Source: Authors elaboration, (2022)
project included mapping
the seafloor of the upper Fan
using a hull-mounted multi-
beam echo sounder (MBES)
(first mission in 2012) and
sampling the substrate us-
ing a 6 m long piston core
(second mission in 2015). In
the first mission, numerous
active gas escape plumes
were identified in the water
column and pockmarks on
the seabed. From this infor-
mation, the second mission
was formulated to sample
core sediments in specific
targets, previously identified Figure 2y: Photograph of piston core
with MBES data. 10 cores collected in the Foz do Amazonas
were collected that resulted Fan – fine sediments with gas hydrate
in the first recovery of gas nodules (black arrow).
hydrate in deep waters (Fig-
ure 2y) in the Brazilian Equa- Source: Rodrigues et al., (2019).
torial Margin (RODRIGUES et
al., 2019).

628 BLUE ECONOMY State of the Art of Gas Hydrate Occurrences 629