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Figure 1y
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                                                                                                                                      •  IODP _ 155



                Figure X3: Discoveries of the occurrence    PROJECT*) and Rio Grande Cone, Pelotas
                of GH in Brazilian territory: Amazon    Basin (CONEGAS Project*) *Projects de-
                                                                                                                                                                   '=D
                Fan, Foz do Amazonas Basin (TUCUXI      veloped by IPR/PUCRS.                                                                    o               o  o  '  o
                                                              Source: Adapted from Ketzer et al., (2021).                                              100    200
                                                                                                                                                                km
               The Foz do Amazonas  Deep-sea Fan Gas Hydrates Province
                 The Foz do Amazonas Cone is approxi-   about the sediments deposited there were
               mately 250 km from the mouth of the Am-  cored and profiled (FLOOD et al., 1995).                                                                               - 3 0 0 0
               azon River. This sedimentary Fan extends    The movement of this thick sequence of                                                                                   -2800
               for 700 km seaward, from the outer edge   sediments, predominantly composed of mass
               of the continental shelf to water depths   wasting and turbidite deposits (channel-le-
               of more than 4,000 m in the Demerara     vee), caused the gravitational collapse of the
               Abyssal Plain (Fig. 1y). It occupies an area   region, resulting in the establishment of ex-
               of  330,000 Km² and 9 km of sedimentary   tensional dynamics in the proximal part and

               thickness (SILVA et al., 1999; DAMUTH and   compressive in the distal part, with the conse-
               KUMAR, 1975). This feature began its for-  quent formation of normal faulting and fold-
                                                                                                                                      •
               mation in the Lower Miocene, through the   ing systems, responsible for the formation of                               *   Gas Plums
               accumulation of sediments whose source   gaps of up to 500 m in the seabed (FLOOD                                          Gas Hidrates
               area is attributed to the uplift of the Andes   et al., 1991; REIS et al., 2010, 2016; SILVA et                            10km                                                         10 km
               Mountains and the consequent reversal of   al., 2016). The triggering of giant mass wast-                         1.00
               the direction of the Amazon River to the   ing events (BTMs) has been associated with
               northeast (FIGUEIREDO  et al., 2009). The   variations caused by climate during sea level                       �  2.00
                                                                                                                               1-
               IODP mission #155 made important contri-  changes (MASLIN et al., 2005). More recent-                             3.00
               butions to the knowledge concerning the   ly, during the Neogene, BTMs are associated
               tectono-sedimentary evolution of this area.   with tectonic activity within the upper part of                     4.00
               17 wells with up to 450 m of information   the slope (REIS et al., 2016).                                                                                     Source: Modified from Ketzer et. al., (2018).


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     626   BLUE ECONOMY                                                                                                                                                               State of the Art of Gas Hydrate Occurrences 627
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