Page 636 - Economia Azul - versão: inglês

Figura Z2
Figure Z2: Pockmark PC22, Rio Grande Cone. autonomous submarine vehicle (AUV) mul-
A) Bottom backscatter image (side scan and tibeam bathymetry, providing a detailed
multibeam sonar – AUV data) associated understanding of the ocean floor, allowing
with water column data, illustrating the
association between bottom features and the location of pockmarks and outcropping
fluid escape (plumes). B) Detail of the faults. Data were also collected from the wa-
PC22 pockmark and its relief where several ter column that allowed the identification
piston cores were recovered. Source: of plumes (MILLER et al., 2015) associated
Authors elaboration, 2022 with pockmarks (Figure Z2). Samples of gas
As of 2010, the knowledge of the RGC hydrates and free gas associated with fluid
has been greatly advanced through the ex- escape zones (chimneys) were recovered in
ecution of the CONEGAS Project (PUCRS/ more than a dozen locations and sampling
PETROBRAS scientific cooperation term). points by piston core and gas collection by
During a decade, six oceanographic cruises submarine vehicle - ROV, in d-column ‘water
were carried out to collect geological and between 500 and 1500 m deep. RGC gas
geophysical information at different posi- hydrates occur as sheets, nodules dissemi-
tions in the RGC. The central region of the nated in the mud matrix, tubes and massive
cone was mapped with hull-mounted and layers (up to 25 cm thick; Figure Z3).

Figure Z3: Examples of
the different forms of
hydrates recovered in
RGC cores. (a) laminate
between 3 and 3 cm
thick); (b) Granules
disseminated in muddy
deposits (red arrows); (c)
massive nodules (2-3 cm
in diameter); (d) pipes
(1-2 cm in diameter);
(e) solid layers up to
25 cm thick; (f) orange
flames resulting from
the combustion of gas
hydrates.

Source: Adapted from Miller,
(2015))

Source: Authors elaboration (2022)

634 ECONOMIA AZUL State of the Art of Gas Hydrate Occurrences 635
634 BLUE ECONOMY