Myanmar1

Myanmar Offshore

This NW-SE schematic geological cross-section suggests the more likely geological context of the Andaman geographic basin, i.e., the plunging of Pacific lithospheric plate forming B-Type subduction zone with formation, in the overriding plate of a trench fill, an accretionary wedge, a forearc basin, a volcanic arc, interarc basins with oceanization covered by non Atlantic-type divergent margins, a backarc basin, in which a rifting and sag phases can be individualized, and intracratonic rift-type basins. Notice that if the lengthening of the backarc basin is big enough, an oceanization (breakup of the continental crust) occurs and a non Atlantic-type divergent margin is deposited and covered by a marginal sea. The knowledge of such a geological context strongly help the tentative interpretation of the Canvas autotraces of the seismic lines of the area. In fact, at least in the oil companies, it is well known that an interpreter (geoscientist in charge of the tentative interpretations of the seismic lines) just recognize, on a seismic line, what he knows. For instance, if he does not know, a priori, what is forearc or an accretionary wedge he can send hours or weeks observing a seismic line, but he never recognizes it. The large majority of the geoscientists follow Karl Popper, i.e., they believe that Theory precedes Observation (Karl Popper, 1934) and not the opposite. Therefore, the knowledge of the location of a seismic line of the autotrace is an indispensable step for, a coherent tentative geological interpretation, i.e., a tentative difficult to falsify, as illustrated on the next plate.

This tentative interpretation of a Canvas autotrace of a seismic line, located eastward of the volcanic arc, illustrates a backarc basin without oceanization, that is to say, that the lengthening of the continental crust behind the volcanic arc was not enough to breakup the continental crust at this place. However, eastward of this backarc basin, the continental crust broke-down by lengthening opening a marginal sea (recognized, clearly, on the Google location map), allowing the deposition of a non Atlantic-type divergent margin looking eastward, which onlaps over the backarc basin illustrated on this tentative interpretation.