Hukum Original Horizontality vs Clinoform

Scr tradisionil sedimen di endapkan dlm keadaan horisontal, atau
tdk // dng lapisan atau dasar cekungan yg ada di bwhnya. (hk
Steno-3 ≈ Original Horizontality of strata).

Dlm sikuen stratigrafi adanya pengendapan yg miring pd
clinoform, krn keadaan ini mengendalikan sedimentasi & urutan
stratigrafi pd umum-nya, walaupun masih mengenali pengendapan
dlm keadaan horisontal yg mrpkn prinsip dasar
mal
mal
Unconformity & Bounding Surface
#1
#2
G
F
G
#3
G
F
B
Dis-Con
F
C
A
Ang-Unc
D
B
A
A
B
E
G
C
F
E
Correlative-ConD
C
G
F
E
D
C
B
A
#1
#2
#3
G
G
G
F
F
F
E
E
E
D
D
C
C
C
B
B
B
A
A
A
D
hiatus
GEOLOGI TIME
B
A
LITHOSTRATIGRAPHY & CHRONOSTRATIGRAPHY
Hypothetical Cross Section
n+2
T0
n+0
n+1
T1
T2
n+3
T3
T4
T5
n+5
n+4
T5
Basement
Alluvial Plain
Coastal Plain
Lithostratigraphy
“A” Sand
Nonmarine Member “X”
“B” Sand
Shale “Z”
Foreshore/ Upper Shoreface
Shoreface/ Shelf
Chronostratigraphy
Unconformity & correlative conformity
Downlap surface & correlative conformity
Unit 1
Unit 2
Unit 3
Correlation Styles
1
2
3
4
5
6
7
8
9
10
11
12
7
8
9
10
11
12
Lithostratigraphic Correlation
1
2
3
4
5
6
Chronostratigraphic Correlation
Alternative Packages
Lithofacies
Regional Seal
Res Sandstone
Shale / Limestone
Sequences
Systems Tracts
TST
HST
HST
LST wedge
BfF
mfs
ts
sb
Controls on Stratigraphic Architecture
EUSTATIC SEA
LEVEL CHANGES
SEDIMENT SUPPLY
BASEMENT
SUBSIDENCE
TECTONIC
EUSTASY
Rise
Uplift
Subsi
dence
∆ Eustacy
∆ Relative
Sea Level
A-S
GEOLOGIC TIME
Fall
RELATIVE SEA LEVEL
(Accomodation Space)
A-S
20m
0m
-20m
300m
0m
300m
100m
0m
10
0 -10
20 10
0
(3)
BALANCED TERRIGENEOUS INFLUX-STATIONARY SHORELINE
final
Relative facies & bedding plane
relationships for balanced.
Sediment influx during a relative
rise of sea level
AGGRADATIONAL
Stationary shoreline
Nonmarine coastal deposit
Lithoral deposit
Marine deposit
Relative sea
level rise
initial
HIGH TERRIGENEOUS INFLUX-REGRESSION
final
Relative sea
level rise
initial
REGRESSION
Shoreline regresses/ advanced seaward due to
deposition relative fall of sea level. Sediment
input > accomodation. Facies sequence shallows up
LOW TERRIGENEOUS INFLUX-TRANSGRESSION
Coastal
agradation
final
Coastal encreament
TRANSGRESSION
Shoreline trangresses/ retreat
landward due to relative rise of sea
level. Accomodation space >
sediment input. Facies deepens up
Relative sea
level rise
initial
(4)
(A) TRANSGRESSION Sea level rise with zero sediment flux
SL time-1
accommodation
INCREASING SEDIMENT FLUX
SL time-0
Transgresion
C. AGGRADATION
(B) RETROGRADATION Sea level rise with low sediment flux
Sea level rise with sediment flux ≈ rate of sea level rise
(D) PROGRADATION Sea level rise with high sediment flux
Regression
PROGADATIONAL PARASEQUENCE SET
DEPOSITIONAL
> ACCOMMODATION
WELL-LOG
RESPONSE
RES
SP
4
3
2
1
RETROGRADATIONAL/ Backstepping PARASEQUENCE SET
DEPOSITIONAL < ACCOMMODATION
SP
RES
SP
RES
BASINWARD
4
3
2
1
AGGRADATIONAL PARASEQUENCE SET
DEPOSITIONAL
≈ ACCOMMODATION
4
3
2
1
Coastal-plain
Sandstone & mudstone
Shallow marine
Sandstone
Shelf mudstone
1-4 individual parasequences
CU
FU
Illustrasi Sik-Pengendapan (batas bawah & atasnya dicirikan adanya SB, (didlm unit
SP tsb didpt bid diskontinuitas lainnya spt TS & MFS.)
Berdsrkan ciri2 dominasi FU atau CU, PS tsb dng mekanisme scr progradasi, retrogradasi yg scr sistim tract td unit HST, TST, & LST, yg masing2 dipisahkan oleh TS, MFS)
Sequence boundary (SB) Type 1,
FS
Tipe 1, m.a.l turun lebih cepat drpd penurunan dasar cekungan
(Van Wagoner, 1990).
TST
HST
MFS
TS
Fluvial or eustarin SS in incised valleys
LST
Coastal plain SS & MS
Shallow marine SS
SB
Shelf & slope MS & thin SS
Submarine-fan & levee-channel SS
Tipe 1 SB, terbentuk pd saat relative sea level fall di grs pantai
tanpa memperhatikan bentuk cekungannya. Sikuen atas dibatasi
oleh bid unc ke arah daratan pd saat kondisi lowstand. Tipe ini
akan tersusun oleh lowstand system tract.
Sequence boundary (SB) Type 2,
Kecepatan penurunan cekungan lebih cepat drpd m.a.l (Van Wagoner, 1990)
FS
MFS
TST
Shelf MS
SMST
HST
Coastal plain SS & MS
Shallow marine SS
HST
HST
TS
SB
Tipe 2 SB, terbentuk tanpa adanya relative sea level fall. Sikuen
pengendapan tipe ini mrpkn suatu siklus regresif - transgresif
tanpa pengaruh dr lowstand system tract. Sikuen ini tdk dibatasi
oleh bid unc. Batas sikuen nya berada pd permukaan regresi maks
yg terletak pd batas antara pola tumpukan (stacking patterns)
fasies regresif & transgresif
Transgressive Surface
FS
TST
HST
MFS
TS
Fluvial or eustarin SS in incised valleys
Coastal plain SS & MS
LST
Shallow marine SS
Shelf & slope MS & thin SS
Submarine-fan & levee-channel SS
SB

Transgressive Surface (TS) adlh flooding surface (FS) yg terbentuk stlh
jangka waktu regresi maks pd top dr Lowstand System Tract (LST)

Dlm skala regional, TS ini memisahkan parasequence progradational atau
aggradational LST yg terletak di bwhnya dgn parasikuen Backstepping
transgressive system tract yg terletak di atasnya.

TS berasosiasi dgn suatu fasies discontinuity, yg dicirikan oleh pendalam
an mendadak yg memotong bid batas. Penggabungan TS dg sequence
boundary (SB) dlm suatu arah menuju daratan akan menyebabkan endapan2 Transgressive System Tract (TST) mengendap scr langsung di
atas endpn Highstand Sytem Tract (HST) yg terletak di bawahnya
FS
Maximum flooding surface
TST
HST
MFS
TS
Fluvial or eustarin SS in incised valleys
Coastal plain SS & MS
LST
Shallow marine SS
Shelf & slope MS & thin SS
Submarine-fan & levee-channel SS
SB
• Maximum flooding surface (MFS) adlh marine flooding surface (top parasikuen) yg
terbentuk pd waktu transgresi maks. Pd kondisi transgresi, laju kenaikan m.a.l relatif akan melebihi laju suplai sedimen ke dlm cekungan. Kenaikan m.a.l relatif ini
akan mencapai maks & kmdn mengalami penurunan shg sistem pengendapan berubah dr yg semula ke arah cekungan (basinward) menjadi ke arah darat (landward).
• MFS membentuk top TST, & memisahkan backstepping parasequence (parasikuen
lebih muda di endapkan jauh ke daratan) yg terletak di bawahnya dgn progradational parasequence (parasikuen lebih muda diendapkan jauh ke cekungan) di
atasnya.
• Bidang MFS bersifat synchronous & mempunyai kenampakan yg paling mudah
diidentifikasi shg baik sbg marker korelasi yg mewakili kesamaan waktu.
Depositional System
Depositional System
Depositional System
LOWSTAND CLASTIC STACKING
FLUVIAL, DELTA & SHELF MARGIN SETTINGS
CHANNEL-POINT BAR
Alluvial or Fluvial
PROGRADING
COASTAL PLAIN
5m
Proximal Fan
Basement
PROGRADING DELTA
MARGIN
25 m
Near Shore
Marine Shale
25 m
Fluvial
stacking
erosion
C-U
SEA LEVEL & SYSTEM TRACT
S.M.S.T
PROXIMAL
H.S.T
SLOPE
CHANNEL
H.S.T
T.S.T
S.M.S.T
H.S.T
F.S.ST
stacking
L.S.T
25 m
T.S.T
DEEP SEA SETTINGS
INNER FAN
CHANNEL
MIDDLE FAN
CHANNEL
SUPRA-FAN
LOBES
DISTAL
BASIN PLAIN
Transgressive Clastic Stacking
CLASTIC MARINE SETTINGS
PROXIMAL
Near Shore
Marine Shale
Proximal Fan
Basement
DISTAL
TRANSGRESSIVE MARINE SHELF
F-U
25 m
Fluvial
lag
C-U
SEA LEVEL & SYSTEM TRACT
S.M.S.T
H.S.T
T.S.T
L.S.T
H.S.T
T.S.T
S.M.S.T
H.S.T
F.S.ST
DELTA BORDER TRANSGRESSIONINE SHELF
Highstand Clastic Stacking
FLUVIAL, DELTA & SHELF MARGIN SETTINGS
C-U
SEA LEVEL &
SYSTEM TRACT
S.M.S.T
H.S.T
T.S.T
L.S.T
H.S.T
T.S.T
S.M.S.T
H.S.T
25 m
PROGRADING DELTA
MARGIN
stacking
Proximal Fan
Basement
PROGRADING
COASTAL PLAIN
25 m
Near Shore
Marine Shale
CHANNEL-POINT BAR
Alluvial or Fluvial
5m
Fluvial
Shoreline Evolution during an
Accommodation Cycle
Depositional Sequence in Space & Time
SB2
DEPTH
TST
SB1
INCISED
VALLEY
(lvf)
TS
CANYON
mf/co
lsf
fls
mf/co
SMW
HST
TST
SHALLOW
DEEP
SB2
SB1
SUBSIDENCE
Time
pgc
lst
EUSTASY
HIGH
LSW
DISTANCE
tfs
fc
ft
Depositional Sequence in Space & Time
SMW
HST
TST
LSW
SB1
SB2
SB1
INCISED
VALLEY
(lvf)
TS
CANYON
mf/co
lsf
fls
Time
tfs
DEEP
SHALLOW
SUBSIDENCE
SB2
TST
mf/co
pgc
HIGH
lst
EUSTASY
DEPTH
In DEPTH
fc
ft
In GEOLOGIC TIME
UNC
Correlative
conformity (≈SB)
SMW
SB2
HST
GEOLOGIC TIME
TS
lvf
UNC
SUBAERIAL HIATUS
SB1
HST
DISTANCE
CONDENSED SECTION
pgc
Correlative
conformity (≈SB)
lsw
mfs
TST
tmf/co
mf/co
tfs
LST
fc
fl
lsf
MAJOR SEQUENCE STRATIGRAPHIC & CHONOSTRATIGRAPHIC SURTACES
DEPTH
SP
10
100
50
21
23
20
22
200
150
24
25
19
8
26
1
2
3
4
5
6
7
9
10 11
27
28
29
30
18
16 17
12
13
14
15
24
CU
FU
The boundaries & surfaces used to characterize sequences & their Systems Tracts are: The enveloping sequence
boundaries (SB) of a sequence lieing between the Highstand Systems Tract (HST) and the Falling Stage Systems
Tract (FSST); upper boundary of Falling Stage Systems Tract (FSST) (Plint and Nummedal, 2000) (also known as
the Early Lowstand Systems Tract (ELST) (Posamentier and Allen, 1999); Transgressive surface (TS) that lies
over the Lowstand Sytem Tract (LST) and the Transgressive Systems Tract (TST); and Maximum Flooding
surface (mfs).
Coastal Onlap Curve
9
0
8
7
6
5
HIATUS
3
20
D
4
10
2
10
CHRONOSTRATIGRAPHIC CHART
5
15
11
1
C
B
A
25
CHRONOSTRATIGRAPHIC APPLICATIONS
11
400
9
0
58
15
COASTAL ONLAP
CURVE
meter
10
-100
0
E
COASTAL TOPLAP
7 8
6
BCD
5
Fall
COASTAL
AGGRADATION
20
1
25
HIGHSTAND
SUPER
CYCLES
D
4
2
CYCLES
C
3
B
SHELF EDGE
BASIN SEA
10
TIME (Ma)
5
200
A
RELATIVE CHANGE of SEA LEVEL FALL
LOWSTAND
E
± 263 Feet
Outcrop to Seismic Comparison
Parasequence (1m to 10 m)
Flooding
Surface /
Parasequence
Boundary
parasequence, terdapat daur berfrekuensi tinggi (order 4 atau lebih), maupun
berfrekuensi rendah (order 3 sampai ke 1)
Salah satu daur yang penting dalam stratigrafi sikuen disebut sequence, dimana
batas-batasnya merupakan unconformity yg merupakan sedimentasi dalam 1 cyclus
turun naiknya muka laut.
Bagian-bagian dari daur itu disebut system tracts yang terbagi dalam lowstand (LST),
trangressive(TST) dan higstand system tracts (HST).
Satu system tract terdiri a set parasequence, yg merupakan satu genetically related
units yang ditafsirkan pula sebagai daur kecil, yang dibatasi apa yang disebut marine
flooding surfaces (MFS). Setiap siklus kecil ini dapat dikenal dalam setiap urutan
stratigrafi, dan merupakan daur order ke 4 s/d ke 6, sedangkan penyebabnya
ditafsirkan perubahan iklim dan muka laut secara kecil-kecilan yang dikaitkan dengan
gejala astronomis yang berdaur seperti axial oblixity dan orbit eccentricity dan disebut
Milankovich cycles.
Namun demikian stratigrafi sikuen memperhatikan pula adanya gejala geologi lainnya
yang mempengaruhi urutan yg bersifat cyclic, seperti gejala tektonik (orogenesa) yang
bersifat perulangan (repetitive) dan gejala proses sedimentasi yang bersifat episodic.
Jelas stratigrafi sikuen telah memberikan pengertian mengenai klasifikasi baru yg lain
sama sekali dengan apa yang kita kenal dalam stratigrafi tradisionil seperti satuan
lithostratigrafi (formasi, anggota, kelompok), dan kronostratigrafi (stage, epoch dsb),
dimana kelihatannya tidak ada hubungannya sama sekali antar satuan stratigrafi
tersebut, karena konsep atau cara kita mengamati gejala stratigrafinya sudah lain