I. Define the following (14 marks)
1. Parasequence (7
marks)
2. Sequence Boundary (SB) (7 marks)
Modal
answer
1. Parasequence
Relatively conformable
depositional units bounded by surfaces of marine
flooding, surfaces that separate older strata
from younger and show
an increase in water depth in successively younger strata.
Relatively conformable (that is, containing no major unconformities),
genetically related succession of beds or bedsets bounded by marine-flooding
surfaces or their correlative surfaces.
2. Sequence
Boundary (SB)
The sequence boundary is an
unconformity updip and a correlative conformity downdip. The sequence boundary
is an unconformity updip and a correlative conformity downdip. Where it is an
unconformity, it is a surface of subaerial exposure and erosion.
II. Write short note on each of the
following: (14 marks)
1. Incinced Valley (4 marks)
2. Depositional sequence
(5 marks)
3. Systems Tracts (5 marks)
Modal answer
1.
Incinced Valley
Incised valleys are entrenched fluvial
systems extending their channels basinward and eroding into underlying strata
in response to a relative fall in sea-level. An incised valley is a type-1
sequence boundary.
2.
Depositional sequence
Stratigraphic unit bounded at its top and base by
unconformities or their correlative conformities, and typically embodies a
continuum of depositional environments, from updip (continental) to downdip
(deep marine). Normally it consists of Lowstand systems tracts (LST), Transgressiver
systems tracts (TST) and Highstand systems tracts (HST).
3. Systems
Tracts
Subdivisions of sequences that consist of discrete
depositional units that differ in geometry from other systems tracts and have
distinct boundaries on seismic
data. Different systems tracts are considered to represent different phases of eustatic
changes. They comprise Lowstand systems tracts
(LST), Transgressiver systems tracts (TST), Highstand systems tracts (HST),
Shelf margin systems tracts (SMST), Regressive Forced systems tracts (RFST) and
Mid-stand systems tracts (MSST).
III.
Complete the following (14 marks)
1. Parasequence
stacking pattern are ………………….……………………..
and …………………………………………...
2. Parasequence types include are
…………………………………, and……...
…………………….. .
3. The
main types of systems tracts are …………………………., ……………
………… ,…………………….., …………………… and ………………….
4. The
main bodies of lowstand systems tracts are ……………….., ………….
…………………, …………………, ….………… and ……………………..
5. Condensed section is ……………………………………………………….
6. The sedimentary
basin is …………………………………………………….
…………………………………………………………………………………
………………………………………………………………………………..
7. Basin components include ……………, …………………, …………….
………………………,……………………………,…………………………. ………………………, …………………………and ……………………….
8. The main basins controls are
………………………, ……………………
……………………………………….and ……………….............................
9. Upstream
in the sequence stratigraphy of the fluvial systems include .
……………………, ………………………, …………………………….,
…………………………………., and
…………………………………
10. Down
stream in the sequence stratigraphy of the fluvial systems
include…………………………………., and …………………………
Modal answer
1. Parasequence stacking pattern are progradational stacking,
aggradational Stacking, retrogradational stacking patterns
2. Parasequence types include are Coarsening
(swallowing) upward, and fining (deepening) upward parasequences
3. The main types of
systems tracts are Falling Stage Systems Tract
(FSST) , Lowstand Systems Tract (LST),
Transgressive Systems Tract (TST), Highstand
Systems Tract (HST), and Regressive System
Tract (RFST).
4. The main bodies of
lowstand systems tracts are Lowstand fans, basin floor fans, lowstand
wedge, mid fans and distal fans
5. Condensed section
is a thin marine stratigraphic interval characterized by very slow
depositional rates (<1-10 mm/yr).
6. Sedimentary basin
is geologically depressed area with thick
sediments (sedimentary rocks) in the interior and thinner sediments at the
edges. A depression, created as a consequence of subsidence, that fills with
sediments.
7. Basin components include Backarc basins, Forearc basins, passive
margin basins, Epicontinental basins, Extensional basins, subduction realated
basins, rift basins, foreland basins (peripheral) and transform
fault (pull apart) basins.
8. The main basins controls
are sediment supply, regional tectonics, sea level changes and climate
9. Upstream in the sequence stratigraphy of the fluvial systems include Climatic
discharge, geology load, tectonic tilting, faulting and drainage basin.
10.
Down stream in the sequence
stratigraphy of the fluvial systems include
Eustasy and
subsidence rate.
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