Changes

Tractive structures, product of the movement of bottom currents that form, are abundant and the most common are ripples currents and cross lamination. Some authors propose that flasser and lenticular-like structures characterized this type of deposit and different from others, as they reflect the variation in the intensity of the current, as well as the selection of grain selection (grading) and erosive scars also represent the same processes. Other common structures are horizontally or sinusoidal lamination, parallel lamination, crossbedding, pebblelags, etc. The preservation of these depends greatly on the degree of bioturbation that can reach delete left a massive structure.

Tractive structures, product of the movement of bottom currents that form, are abundant and the most common are ripples currents and cross lamination. Some authors propose that flasser and lenticular-like structures characterized this type of deposit and different from others, as they reflect the variation in the intensity of the current, as well as the selection of grain selection (grading) and erosive scars also represent the same processes. Other common structures are horizontally or sinusoidal lamination, parallel lamination, crossbedding, pebblelags, etc. The preservation of these depends greatly on the degree of bioturbation that can reach delete left a massive structure.

 

Biogenic structures are usually diagnostic features of contourite deposits when conditions favor the benthic life and when the speed of the current cannot erase them. The mottling is the common structure sizes ranging from millimetric to centimetric but also usually appear ichnofacies like fodichnia, pascichnia and domichnia. The factor that primarily affects their absence or abundance is the oxygenation of the ocean floor.

Biogenic structures are usually diagnostic features of contourite deposits when conditions favor the benthic life and when the speed of the current cannot erase them. The mottling is the common structure sizes ranging from millimetric to centimetric but also usually appear ichnofacies like fodichnia, pascichnia and domichnia. The factor that primarily affects their absence or abundance is the oxygenation of the ocean floor.

As for the fossil content, it depends on the parent material reworked, being common remains of planktonic animals.

As for the fossil content, it depends on the parent material reworked, being common remains of planktonic animals.

Gao et al. (1998) propose a facies classification based on grain size and the composition so there are muddy contourites, silty contourites, sandy contourites, gravel-lag contourites and bioclastic contourites, the first three with their calcareous variations (Figure 3). The most common in current deposits is muddy type, in which predominates the clay size with diffuse stratification and parallel lamination, bioturbation and organic traces. Among the most common fossils contourites, are sandy facies wich are well selected and stratified with gradations and bioturbation and organic traces can be abundant predominates.

Gao et al. (1998) propose a facies classification based on grain size and the composition so there are muddy contourites, silty contourites, sandy contourites, gravel-lag contourites and bioclastic contourites, the first three with their calcareous variations (Figure 3). The most common in current deposits is muddy type, in which predominates the clay size with diffuse stratification and parallel lamination, bioturbation and organic traces. Among the most common fossils contourites, are sandy facies wich are well selected and stratified with gradations and bioturbation and organic traces can be abundant predominates.

Another facies classification is proposed by Stow et al (1996). They propose that there clastic contourites (muddy, silty, sandy, gravel lag, micro-brecciated) biogenic (carbonate or siliceous) chemogenic and also the shallow water contourites.

Another facies classification is proposed by Stow et al (1996). They propose that there clastic contourites (muddy, silty, sandy, gravel lag, micro-brecciated) biogenic (carbonate or siliceous) chemogenic and also the shallow water contourites.

The depositional features can be classified into shallow (less than 300m), intermediate (between 300 and 2000 m) and deep drifts (more than 2000m). The most widely used classification (Rebesco, 2005) is based on its morphological, sedimentological and seismic characteristics shown in Figure 3.

The depositional features can be classified into shallow (less than 300m), intermediate (between 300 and 2000 m) and deep drifts (more than 2000m). The most widely used classification (Rebesco, 2005) is based on its morphological, sedimentological and seismic characteristics shown in Figure 3.