Sedimentary System Analysis
| Courses and exams | |
|---|---|
| Prof | Gerardus Weltje |
| Courses | Lectures, practicals and 1 excursion |
| Examen | Assignments and written exam |
| Background | |
| Credits | 6 |
| When? | Master, 1st semester |
| Skip? | Possible |
| ECTS | Link |
Weltje is the most weird man ever. Everything he does seems made up at the moment he tells it. You will do some well-logging on a digital borehole. He is really proud of it. Excursion is really muddy, so be prepared! This is a new course (2023). Questions are from a previous course: Generation and Architecture of Sedimentary Basin Fills.
January 2025
- System tracks
- Draw the base level cycle and give extra attention to the sequence boundary (chapter 1, slide 62).
- What is the difference of the definition of the sequence boundary between the 'Exxon slug' with three system tracks and the enhanced model with four system tracks?
- Fluvial systems
- Picture given. Which surfaces (1-4) can you see? Which system tracks can you see between the surfaces? Which system track is missing and why? How can you distinguish the system track between 2 and 3 from the other two?
- Do the Carboniferious cyclotherms work according to the river sequence stratigraphy?
- Grain-size analysis
- Give three examples of how you can perform grain size analysis. For each example, is there a link with their density or shape?
- Explain how and why this is important for reservoir geology.
- Delta's
- Three types of deltas (river, wave-and tidal dominated) and there link with the spatial distribution of mud and sand.
- ...
January 2025 Question 2: Stratigraphic architecture of fluvial depositional sequence
January 2024
- A question about deltas: three types of deltas (river, wave-and tidal dominated) and there link with the spatial distribution of mud and sand.
- Do the Carboniferious cyclotherms work according to the river sequence stratigraphy?
- Give three examples of how you can perform grain size analysis. For each example, is there a link with their density or shape?
- Give three examples of when turbidites can occur in highstand.
- Give the four system tracks and their stacking pattern in the correct order.
- Give the five steps of how you should prepare ... (something of the last lesson).
- Briefly explain three examples of event-stratigraphy (For example tephrostratigraphy).
- Explain the physical and chemical functioning of the dipmeter and its succesor FMI and their operational conditions. Additionally, give three examples (structural geology and sedimentology) of how they can be used.
January 2021
De curves (die van de eerste lessen) die zeespiegelschommelingen met accommodatie en sedimentatie combineert met systems tracks uitleggen was vraag 1, verder een vraag over barrier islands, een vraag over event stratigrafie, cyclotherms en het verschil tussen processed based en geostatiatical models
January 2018
The first five questions are about the part of professor Weltje and the last question is from the part given by professor Speijer. This was an oral exam aside from that last question.
- Draw a relative base-level cycle (as a function of time) and clearly indicate the positions of the systems tracts and their bounding surfaces. Also include the corresponding shoreline movements using the appropriate terminology. For convenience you may assume a constant sediment supply.
- Describe the process of avulsion. What is its role in sequence stratigraphy? (He was looking for crevasse splay and isochron)
- Parasequence and Sequence
- Give definitions
- Can you think of a (hypothetical) situation in which a sequence passes laterally into a parasequence? Hint: Think of the dimensionless ratio
- Give the definition of Walther's Law and explain how it relates to the two different methods of correlation being used. Can it be used to predict facies changes across unconformities?
- Tropical Carbonate factories and the main sediment production and export (to the deep-sea)
- Describe and compare to the siliciclastic sediment export (in terms of HST or FSST+LST)
- Do the unconformities form in the same way? (Looking for drowning unconformity)
- Describe the main differences in depositional style between the tropical carbonate factory and the other two carbonate factories. (looking for reef gradient etc.)
- Tephrostratigraphy
- Describe the main principles of tephrostratigraphy
- Give the advantages and disadvantages (and any problems) that could occur with correlation
January 2016
The first five questions are about the part of professor Weltje and the last question is from the part given by professor Speijer. This was an oral exam aside from that last question.
- Draw a base-level cycle as a function of time and clearly indicate the positions of the systems tracts and the bounding surfaces.
- In longitudinal sections through a depositional system(parallel to the main sediment transport direction), each systems tract is characterized by a shoreline trajectory. Each shoreline trajectory may be explained in terms of stacking patterns.
- List the systems tracts of the enhanced sequence model in their correct order.
- Describe the shoreline trajectories and stacking patterns within each systems tract.
- Does the enhanced sequence model differ from the classic sequence model with respect to the location of the sequence boundary? Explain your answer.
- This figure (see right side of the page) represents a cross section ofa fluvial valley, showing a large number of stacked channel fills encased in fine-grained floodplain deposits.
- Name the bounding surfaces (numbered 1 to 4) and the three systems tracts they enclose. Explain why one systems tract is missing (which one?).
- A geologist who has studied these deposits claims that the channel fills located between surf aces 2 and 3 are different from the other channel fills. What could he/she be referring to? NB: Feel free to be witty at this point, even though an answer such as "The colour: they are blue" is unlikely to count towards your final mark.
- Is the above sequence model applicable to Carboniferous cyclothems such as those exposed in Kentucky? Explain your answer.
- What is the relation between planform geometries ofturbidite channels as observed on the ocean floor and their equilibrium profile (base level)?Explain your answer by drawing the planforms together with expected cross sections (parallel and perpendicular to the slope) of the turbidite channels.
- Throughout a relative sea-level cycle, tropical carbonate factories display a characteristic pattern of sediment export to deep water. The same may be said of siliciclastic systems.
- What is the timing of maximum and minimum sediment export in each of the two systems?
- Suppose that a deep basin is bordered by a tropical carbonate factoryanda siliciclastic shelf, which export the same volumes of sediment when summed over an entire relative-sea-level cycle. How do you expect that the composition ofthe sediment (expressed as relative contributions of carbonate versus siliciclastic material) in the deep basin bordering these systems changes throughout the cycle?
- Do unconformities in carbonate systems always form under the same conditions as in siliciclastic systems?
- Discuss what is shown in the graph below (see right side of the page) and reconstruct the geological history on the basis of the information given.