5/12/2023 0 Comments Submarine canyon![]() The vertical resolution of standard logging measurements can be much larger than the lithology change scale of the submarine channels, which can cause inaccurate formation evaluation results. Fig. 1.30 illustrates the typical depositional model for deep water mudrock-rich turbidites formations. The submarine channels because of gravity-flow often are highly heterogeneous and have thin-bed channels or layers, and the lithology of the associated leveed channels changes rapidly at centimeter scale ( Basu et al., 2007). Above that feature, there are very smooth circular depressions (pockmarks) with a diameter of about 900 m ( Figure 19).ĭeep water turbidites formations, which consist mainly of the submarine channels and depositional lobes, can have large amounts of hydrocarbon in-place interbedded with shaly-sand and shale layers. That erosion scar is arranged in a northwest-southeast direction, generates a relief of about 170 m and has declivity of 8 degrees and reaches the edges of both canyons previously mentioned. ![]() At the base of the slope, at a depth of approximately 1,184 m, the escarpment of an erosion scar stands out as the main irregularity of the area. The region of the slope between the Almirante Câmara Canyon and the Tabajara Canyon has a smooth convex profile with declivity varying from 2 to 3 degrees. Both channels branch off into several intertwined small channels in front of the canyon mouth. The scars alternate in the opposite sites of the channel edge, conferring the high sinuosity of the inner channel talweg.įrom 830 m water depth onwards, a second, still incipient, channel emerges from the base of the left wall and extends, with very low sinuosity, into the central portion of the trough and parallel to the main inner channel, which, from that region on, runs along the right edge of the canyon trough. Throughout its length, Almirante Câmara Canyon inner channel is bordered by steep semicircular scars formed by the collapse of the channel edges. The average value of the channel width is 820 m. The width of the channel varies from 1,230 m next to the canyon’s head and decreases to 615 m at the mouth. The average declivity along the talweg line is about 6 degrees. The average declivity of the wall of the left margin is 23 degrees and, of the right margin, 24 degrees. The average relief of the left margin wall is 144 m, and of the right margin, 124 m. The cross-sectional profile of the channel has no significant asymmetry. The wall gradient varies from 80 m to 255 m (134 m average). The envelope of this inner channel has moderate sinuosity (1.2), accompanying the sinuosity of the canyon however, its talweg has a higher sinuosity (1.3). From there, it turns to the southeast to divert from a halokinetic diapir in the São Paulo Plateau and meets the Tabajara Canyon, to form the channel complex of the Almirante Câmera System, downstream. This long channel is sinuous while inside the canyon and becomes straighter outside of it, from 1,450 m water depth onwards. The submarine channel inside the submarine valley of Almirante Câmara Canyon extends from the canyon’s head to beyond the mouth ( Figure 19). Anderson Gomes de Almeida, Renato Oscar Kowsmann, in Geology and Geomorphology, 2016 5.2 Almirante Câmara Canyon inner channel
0 Comments
Leave a Reply. |