The Garzan Formation is a deepening upward marine carbonate
including successions ranging from subtidal to open marine facies deposited
in the Maastrichtian. The Garzan Formation is composed of five microfacies
types / Miliolid Wackestone (subtidal), Orbitoid Miliolid Wackestone, Rudist
Wackestone (backshoal to shoal), Rotalid Miliolid Wackestone (shoal to
foreshoal) and Pelagic Foraminiferal Mudstone (foreshoal to open marine).
These five microfacies are stacked in different combinations consisting
of five types of depositional cycles. The type A and D cycles the building
blocks of transgressive systems tract (retrogradational), whereas type B and
C cycles are deposited during highstand systems tract (aggradational). The
type E cycle is progradational and also corresponds to the highstand systems
tract deposits. The maximum flooding surface is usually located within the
type D cycle towards the top of the formation.
vi
Generally, the base of the Garzan Formation deposition starts with
highstand systems tract deposits (type E and C cycles) and overlain by
transgressive systems tract deposits (type A cycle) in between there is a type
2 sequence boundary. Then deposition continues with highstand systems
tract deposits (alternation of type B and C cycles) which are aggradational in
character. The top of the Formation is characterized by transgressive
systems tract deposits (type D cycle) which usually includes the maximum
flooding surface. The second type 2 sequence boundary is located below the
type D cycle.
There are four of the stacking patterns observed in the Garzan
Formation. The GR values change from relatively high to low API in type D
and A cycles, whereas a relative shift from low to high API is observed in
type E cycle. The GR in the type B and C cycles does not display any relative
change. There is no net movement in the SONIC readings in type A, B, C
and E cycles / however there is a relative shifting from low velocity to high
velocity in type D cycle.
In Garzan deposition opposing the general patterns, a decrease in GR
readings indicates a decrease in energy and relatively deepening. In
carbonate depositional systems predicting the depositional environment from
the logs should only be accomplished with microfacies control, otherwise the
interpretation will be erroneous.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12609648/index.pdf |
| Date | 01 June 2008 |
| Creators | Yildizel, Zeynep Elif Gaziulusoy |
| Contributors | Altiner, Demir |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
Page generated in 0.0023 seconds