Search > Namibia VERNOB-03 Survey > Namibia VERNOB-03 - another profile from the continental margin Regional Project > Shallow section with faulted clinoforms - offshore Namibia Scene


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Seismic stratigraphy exercise Interpretation

VSA Author: Julien Moreau
Date Created: 2013-09-12

Correction of a seismic interpretation exercise I gave. The interpretation is uniquely based on reflection termination picking which indicate bounding surfaces. No model is involved. Colours between two successive bounding surfaces have no genetic meaning they only give a sort of chronology through the repetition of a colour cycle (blue, pink, green,yellow) . The objective of the exercise is to emphasize the technical rigour which in turns allow in-depth interpretations. The drastic changes in the platform geometry are quite impressive. In particular the collapse events are spectacular in the sense that few of the fallen material remains locally and has been reworked probably downslope (or laterally by oceanic bottom currents). After the students have done the seismic stratigraphy of profile scene, I have printed my interpretation (as above) on A0 paper. The students then cut out each sequence and organise them in a way that sequences do not overlap vertically. By doing so, a Wheeler diagram is created which is a temporal and spacial representation of the filling of the basin. This is available via the docs and links to this interpretation. The students can then measure the minimum available space evolution through sequences as well as an estimate of the sedimentary supply (by counting the number of phases/sequence). In addition a coastal onlap curve can be produced (not shown here). The combination of the 3 curves allows to constrain and understand the dynamic of the basin. There are profound changes affecting this margin which inculde palaeoceanographic and climate modifications which can be evidenced and discussed with the students. By observing these signals, the students can get a grasp on how sequence stratigraphy models have been originally created. They also learn by the example the limitations and inaccuracies of these models.





Details:

  • Interpretation Administrator:
    • Julien Moreau
  • VSA Author:
    • Julien Moreau

Geological Interpretation

Deformation Structures
Normal Faults

Seismic Stratigraphy
Erosional truncation, Toplap, Downlap, Onlap

Depositional Architecture
Erosional, Channel / Channel Levee, Clinoform, Sheet deposit

Depositional Environment
Shelf, Upper, Fluvial / Alluvial

Depositional Processes
Turbidites, Hemipelagic Fallout, Mass Wasting and Transport

Sediment Composition
Siliciclastics

Geological Context

Plate Settings and Margins
Passive

Tectonics
Gravity, Strata-bound

Basin Setting
Passive Margin

Geographic Context

Physical Geography
Shelves, Fans (Submarine)

Political Geography
Namibia, Republic of

Seismic Oceanography

Oceans
S Atlantic

Processes
Along Slope Flows

Geophysics

Data Presentation
Vertical Scale - Time, Amplitude

Image Type
Vertical Profile