Sequence Stratigraphy of the South Texas
Oligocene: Understanding the
Relationship Between Shale Tectonism
and Lowstand Deposition
R. Treviño, L.F. Brown, R. Loucks, and U. Hammes
Bureau of Economic Geology
Jackson School of Geosciences
The University of Texas at Austin
A New Depositional Model for
the Frio / Vicksburg
Overview
• Location
• South Texas Growth-Faulted Subbasins
• Stratigraphy – Structure Interplay
• Dynamic Model
• Exploration Potential
Location Map
20 Miles
30 Km
Outer Limit of
Texas State Waters
Salt Domes
Corpus Christi
Corpus
Christi
Bay
Seismic Line in Corpus Christi Bay
Schematic representation - successive
growth-faulted intraslope subbasins
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Organization of sands
(after Mitchum and Van Wagoner, 1991)
~1000 ft
~1 mi
1
2
?
Origin of Growth-Faulted Subbasins
Related to the interaction of:
- gravity tectonics,
- relative sea-level changes,
- and sediment supply.
Wireline-log sequence stratigraphy
Basin-floor fans
T1
?
Wireline-log sequence stratigraphy
Slope fans
?
Wireline-log sequence stratigraphy
Lowstand
TS
prograding
T1
wedge
TS
T1
TS
?
Wireline-log sequence stratigraphy
Lowstand prograding wedge
TS
LST:pw
T1
TST
LST:pw
T1
HST
mfs = mcs
TS
TS
Organization of sands
~1000 ft
~1 mi
1
2
?
Early Lowstand Systems Tract
Incised valleys commonly
erode at fault intersections
LST Prograding Wedges
Pelagic deposition
Depositional systems after Galloway et al., 1982
Schematic representation of successive growthfaulted intraslope subbasins
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Dynamic Depositional Model
Conclusions
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
?
5
•
Offshelf Lowstands overload slope
•
Growth-faulted subbasins younger
basinward
•
Similar log facies, different subbasins =
different time
•
Deep Potential
Acknowledgements
Western Geco – Seismic
Sabco
IBC (now Boss Exploration)
STARR PROGRAM
State of Texas
Advanced Resource Recovery
Organization of sands
(after Mitchum, 1991)
~1000 ft
~1 mi
1
2
?
Organization: Seismic view
Oakville ivf system
Miocene
A n a h u a c HS T
2-order mfs
Anahuac TST
Frio on-shelf HST’s/TST’s
3-order TS + 3-order mfs
Base of shelf
4 - o r d e r L S T: p w # 3
4 - o r d e r L S T: p w # 2
4 - o r d e r L S T: p w # 1
4-order to 6-order sf’s =
3-order sf system
Shale ridge
Schematic representation of successive growthfaulted intraslope subbasins
Organization
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
NW
Regional dip
cross section
using S5 logs
APPROXIMATE
Benthic
Microfossil
Biozones
SE
2
SP
Robulus chamborsi
3
Res.
SP
Res.
4
5
SP Res.
SP Res.
4000
Marginulina
21.53 Ma ascensionensis
23.19 MaLenticulina jeffersonesis
23.97 Ma
Discorbis gravelli
24.39 Ma
24.54 Ma
24.78 Ma
25.20 Ma
25.59 Ma
25.98 Ma
Heterostegina sp.
o
Bolivina perca
Marginulina
idiomorpha
M. vaginata
M. howei
Camerina "A"
Miogypsinoides
"A"
5000
o
o
5E
Cyclammina sp.
26.62 Ma
6000
6
Cibicides
hazzardi
5D
Marginulina
texana
27.33 Ma Bolivina mexicana
27.51 Ma
6
3
o
4 TS
7000
5C
6
Nonion struma
5B
5E
8000
5D
5
28.26 Ma
Nodosaria blanpiedi
28.58 Ma
1
TEXAS
29.01 Ma
2
Discorbis "D"
Anomalina
cocoaensis
Textularia
(mississippiensis)
seligi
CORPUS
CHRISTI
o
5
4
5C
3
5B
5E
9000
o
10000
5D
LST 3
PORTLAND
4
5C
11000
o
?
LST 4
Anomalina bilateralis
3
3
12000
Textularia tumidula
5B
o
LST 2
3
Textularia
mississippiensis
(heavy keel)
Aransas Pass
Oso Bay
13000
2
4
o
LST 1
4
32.4 Ma
o
Textularia warreni
3
Grass
Flats
Laguna Madre
1
3
5A
PADRE ISLAND
PORT ARANSAS
15000
3
3
5
6
4
2
MUSTANG ISLAND
14000
LST
5
1
2
1
6
0
0
Paleo control
5 mi
5 km
16000
?
Faults cutting Frio Fm.
are generalized
17000
?
QAd2176c
?
BASINWARD
18000
Isochron map of lowstand prograding wedges
Sediment input (incised valleys) axes
0
2
Miles
C.I. = 40 ft
pw = lowstand
prograding wedge
Isopach map of lowstand prograding wedges
Sand “40”
net sandstone
isopach
Incised valley feeder systems
U
D
1 mi
1 km
Isopach map of lowstand incised-valley fills
0
1 mi
?
29- Sand
0
1 mi
?
30- Sand
Cross section of incised-valley fills (lowstand)
SE
NE
470 Atlantic 45-47
No. 4
470 Atlantic 45-47
No. 6
445 Getty
No. 1
446 Getty
No. 1
421 Energy/Getty
No. 1
395 Atlantic
No. 1
396 Atlantic
No. 8
349 Operator
No. 7
Feet
TVD
Feet
TVD
Feet
TVD
Feet
TVD
Feet
TVD
Feet
TVD
Feet
TVD
Feet
TVD
ivf
29 sand
ivf
30 sand
Cross section in axes of incised valleys
Cross section is perpendicular to incised valleys
~
From Brown, Loucks, Trevino
(2002)
Wireline-log sequence stratigraphy
Lowstand incised-valley fill,
transgressive, and highstand
systems tracts
?
Wireline-log sequence stratigraphy
Lowstand incisedvalley fill,
transgressive, and
highstand systems
tracts
TST
LST:ivf
HST
TST
LST:ivf
TS
T1
mfs = mcs
TS
T1
HST
Red Fish Bay
S5-Benchmark Chart
Age of
Stratal surfaces (Ma)
Approximate
microfossil biozones+
(benthics)
(All absolute ages [Ma] are
approximate. T1’s after Hardenbol
et al. [1998] and mfs’s after
Wornardt [2000])
Vertical time axis is not time linear
Berggren (1985); recalibrated
to Berggren et al (1995)
2
TST
Textularia “W”
12.5 Ma
12.7 Ma
13.21 Ma
12.7 Ma
13.15 Ma
Depositional sequences,
systems tracts, and surfaces
2nd order
13.4 Ma
14.92 Ma
Cibicides opima
Amphistegina "B"
Robulus "L"
Operculinoides
Gyroidina “6”
Robulus chambersi
2
LST
Minor shale
wedge
15.6 Ma
16.2 Ma
15.8 Ma
16.27 Ma
16.7 Ma
16.4 Ma
HST
1000
17.1 Ma
LST:pw
o
2 T1
1500
HST
TST
3
mfs = mcs
TS
T1
TS
16.8 Ma
2000
pw
mfs = mcs 3
17.21 Ma
17.71 Ma
LST:pw
3 TST
2 TS
o
Pay zones
500
HST
TST
mfs = mcs 3
TS
o
14.7 Ma
Harang Unconformity
14.8 Ma
Log
section
selected
from well
Res.
LST:pw
mfs = mcs
Bigenerina humblei
SP
3 TST
TS
T1
T1
13.6 Ma
14.2 Ma
Composite
log
3rd order# with some
component 4th orders
Based on local subbasin
(T/R cycles)
mfs = mcs
18.6 Ma
18.7 Ma
TS
T1
HST
pw
T1
17.3 Ma
18.0 Ma
HST
2500
3 TST
18.22 Ma
HST
M1
TST
M2
mfs = mcs 3 HST
2
HST
20.52 Ma
21.3 Ma
Siphonina davisi
3
3500
T1
19.5 Ma
19.95 Ma
21.53 Ma
3000
mfs = mcs
& dls
Minor shale
wedge
19.1 Ma
Marginulina
ascensionensis
pw
4000
TST
T1
HST
3 TST
mfs = mcs
21.6 Ma
TS
22.2 Ma
T1
22.9 Ma
23.2 Ma
mfs = mcs
23.6 Ma
T1
M3
4500
pw
5000
HST
22.19 Ma
Lenticulina jeffersonensis
& Liebuselia sp.
M4
TST
TS
23.97 Ma
Discorbis gravelli
24.39 Ma
Heterostegina sp.
24.57 Ma
Bolivina perca
24.78 Ma
Marginulina idiomorpha,
M. vagulata, H. howei
25.2 Ma
Lithostratigraphic
“Anahuac” boundaries
are diachronous
6000
HST
6
M5
3
2 mfs = mcs
& dls
24.57 Ma
2nd-order maximum
flooding and downlap
surface
M6
TST
TS
25.2 Ma
25.38 Ma
T1
Camerina sp.
25.59 Ma
25.98 Ma
10A
10B
9
8
HST
LST:ivf
4 TST
LST:ivf
2
TST
Cibicides hazzardi
26.62 Ma
T1
5E
5
HST
3
5D
LST:ivf
T1
HST
4
5C
LST:ivf
4 HST
27.49 Ma
27.51 Ma
Hackberry unconformity
5B
mfs = mcs
3\4
28
29
30
Base of Shelf
2 TS
32
8500
9000
9500
33
34
35
TST
T1
7500
8000
14 15
17 18
19 20
21
22
31
27.33 Ma
7000
7
6
23
25
27
TST
TS
6500
13
mfs = mcs
4 TST
Marginulina texana
Bolivina mexicana
5500
LST:ivf
23.8 Ma
Miogupsinoides
3
10,000
36
37
4 & 5 pw’s
3 LST:pw
38
39
40
10,500
41
42
Nonion struma
3
4 & 5 pw’s with
thin distal 4 HST’s
and TST’s
43
11,000
44
top sf and local mcs
28.0 Ma
11,500
45
28.26 Ma
4
3 LST:sf
4 & 5 slope
fans = 3 sf
28.58 Ma
T1
28.5 Ma
13,500
50
3 LST:sf
14,000
4 & 5 slope
fans = 3 sf
3
51
(leveed slope
channels)
14,500
T1?
29.4 Ma
2
(Abreu & Haddad, 1998)
3
53
54
30.2 Ma
T1?
31.0 Ma
top bff and local mcs
3 LST:sf
Subbasin
floor
Textularia tumidulm
48
Distal HST
top sf & mcs
Textularia seligi
(mississippiensis)
Anomalina bilateralis
12,500
13,000
3 LST:bff
29.01 Ma
30.4 Ma
12,000
top bff and local mcs
28.4 Ma
28.6 Ma
Discorbis “D”
Anomalina “F” cocoaensis
47
2
LST
Lithostratigraphic
“Frio” boundaries
are diachronous
Subbasin
floor
28.5 Ma
46
(leveed slope
channels)
Nodosaria blanpedi,
Discorbis “D”
&
Anomalina “F”
cocoaensis
1
3 LST:bff
T1
32.0 Ma
32.47 Ma
56
15,500
3 Distal HST
top sf and mcs
16,000
57
58
3 LST:sf
32.4 Ma
15,000
55
3
4 & 5 slope
fans = 3 sf
16,500
(leveed slope
channels)
Textularia warreni
59
17,000
?
3rd- and 4th-order systems tracts
TST
HST
LST:ivf
Transgressive
systems tract
Highstand
systems tract
LST:sf
Lowstand
systems tract:
incised-valley fill
LST:bff
*Supersequence (second-order) boundaries vary slightly from
those of published charts, perhaps because local subbasin
tectonic cycles perturbate global second-order sea-level signals.
+Ages of some benthonic biozones do not agree with some
planktonic and nanofossil zone ages.
# Most on-shelf higher frequency sequences and tracts not
delineated on this chart. See cross sections.
Lowstand
systems tract:
prograding wedge
Lowstand
systems tract:
slope fan
Lowstand
systems tract:
basin-floor fan
LST:pw
o
# Oligocene 3
sequence
designations
Sequence surfaces
T1
mfs = mcs
TS
top sf or bff
M34
o
5E
Designated 4
o
sequences (no. 5 A-E)
in order of deposition
S5-benchmark log showing composite log and sequence stratigraphy of the Redfish Bay area, Texas.
sf
T1
mcs
bff
mcs
Sequence boundary: type 1
(on-shelf intervalley ravinement = TS)
Maximum flooding surface =
condensed section
Transgressive ravinement surface
with coastal onlap
Top slope or basin-floor fan
surface
Marker Bed (top of sandstone bed)
Local autocyclic condensed section
(overlying sf or bff)
Downlap surface (dls)
(progradational HST or LST: pw)
QAd2125c
Section of Red Fish Bay S5-Benchmark Charts
Approximate
microfossil biozones
(benthics)
Age of
Stratal surfaces (Ma)
Depositional sequences,
systems tracts, and surfaces
2nd order
Based on local subbasin
(T/R cycles)
Composite
log
3rd order# with some
SP
component 4th orders
Log
section
selected
from well
Res.
7000
24.78 Ma
Marginulina idiomorpha,
M. vagulata, H. howei
25.2 Ma
6
3
TS
25.2 Ma
25.38 Ma
T1
Camerina sp.
Miogupsinoides
Cibicides hazzardi
26.62 Ma
HST
10A
10B
9
8
LST:ivf
4 TST
LST:ivf
2 TST
25.59 Ma
25.98 Ma
TST
T1
mfs = mcs
5E
T1
Marginulina texana
3
4
TS
7
6
8000
13
HST
4 TST
5
5D
LST:ivf
HST
TST
14 15
17
19 18
20
21
22
23
25
27
5C
LST:ivf
28
29
30
31
4 HST
Bolivina mexicana
27.33 Ma
27.49 Ma
27.51 Ma
Hackberry unconformity
5B
mfs = mcs
3\4T1
TST
Base of Shelf
2 TS
7500
4 & 5 pw’s
3 LST:pw
32
8500
9000
9500
33
34
35
10,000
36
37
38
39
40
10,500
41
42
Nonion struma
3
4 & 5 pw’s with
thin distal 4 HST’s
and TST’s
top sf and local mcs
28.0 Ma
43
11,000
44
11,500
45
28.26 Ma
4
46
12,000
4 & 5 slope
fans =3 sf system
Nodosaria blanpedi,
Discorbis “D”
&
Anomalina “F”
cocoaensis
28.5 Ma
47
Lithostratigraphic
“Frio” boundaries
are diachronous
Subbasin
floor
28.58 Ma
2 LST
13,000
top bff and local mcs
28.4 Ma
28.6 Ma
12,500
28.5 Ma
T1
3 LST:bff
Distal HST
48
13,500
Pay zones
Regional correlations of sands
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
?
5
~1000 ft
~1 mi
So, how do you correlate between subbasins?
Regional dip
cross section
using S5 logs
1
TEXAS
2
CORPUS
CHRISTI
PORTLAND
3
3
Aransas Pass
Oso Bay
4
4
Grass
Flats
Laguna Madre
MUSTANG ISLAND
PADRE ISLAND
PORT ARANSAS
5
6
0
0
5 mi
5 km
Faults cutting Frio Fm.
are generalized
QAd2176c
Site-Specific Sequence-Stratigraphic Section
Benchmark Charts (S5 Benchmark Charts)
• Composite logs with
• Sequence stratigraphy
• additional data
• summarize subbasin geology
• Promote accurate correlations
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Stage in development and filling of growth-faulted
intraslope subbasins: Stage 1
Stage 1: Late highstand systems tract
Shelf edge
LST
Slumped
shelf
edge Prodelta
HST
LST
LST
Maximum relative highstand of sea level
Previous LST tract
Older
shale ridge
Slumped distal
HST muds
~3000-4000 ft
plumes
+/-1000 ft
HST
mfs
TST
HST
HST
SL
Pelagics
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 2
Stage 2: Initial lowstand systems tract:
maximum erosion and basin-floor fan
HST
LST
HST
LST
LST
Maximum rate of relative fall of sea level
Previous HST
fluvial entrenchment
SL
Turbidity flow
Basin-floor fans
Initial
LST
SL
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 3
Stage 3: Early lowstand systems tract:
HST
initial slope fan
HST
LST
LST
LST
Diminishing rate of relative fall of sea level
Previous HST
Subaerial
shelf
SL
Turbidity flow
Slopes fans
Early
LST
SL
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 4
Stage 4: Mid-lowstand systems tract: slope fan and fault activation
HST
HST
LST
LST
LST
Initiation of growth fault, maximum rate
of slope-fan deposition, and maximum
positive accommodation rate near growth fault
Intraslope subbasin
Turbidity flow
Slopes fans
Mobilized basinal shales forming
incipient shale ridge
?
Gravity faluting with major expansion
MidLST
SL
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 5
Stage 5: Late lowstand systems tract:
prograding wedge and decelerating fault movement
Prograding
Incised
valleys Lowstand- wedge
shelf
edge
HST
HST
LST
LST
LST
Maximum lowstand and early relative rise of
sea level and diminishing accommodation rate
Late
LST
SL
Intraslope subbasin
Termination of slope Starved basin MidLST
fan deposition
SL
Pelagics
?
Mobilized basinal
shales
?
?
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 6
Stage 6: Late transgressive systems tract
and maximum flooding
HST
LST
HST
LST
LST
Maximum rate of relative rise of sea level
Transgressive systems tract
Submerged shelf
Maximum
flood SL
Intraslope subbasin
Prograding
wedge delta complex
Starved basin
MidPelagics LST
SL

ivf
?
?
?
Stage in development and filling of growth-faulted intraslope
subbasins: Stage 7
Stage 7: Early highstand systems tract
HST
HST
LST
LST
LST
Decelerating rate of relative rise of sea level
Early HST
Delta front
Transgressive systems tract
mfs & mcs
HST
SL
LST ramp
MidLST
LS

?
?
Schematic representation of successive shifting LST depocenters
Subbasin 2
Shoreline
(old highstand)
Incised
valley
LST 2
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Schematic representation of successive shifting LST depocenters
Subbasin 3
LST 3
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Schematic representation of successive shifting LST depocenters
Subbasin 4
LST 4
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Schematic representation of successive shifting LST depocenters
Subbasin 5
LST 5
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?
Schematic representation of successive shifting LST depocenters
Protosubbasin 6
LST 6
6
Shingled turbidites
on clinoform toes
Incipient intraslope
subbasin no. 6
1
?
?
2
~1000 ft
~1 mi
?
?
?
Unexpanded
older deep-water systems
?
?
?
3
4
5
?