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1. 11/29/21, 5:04 AM Growth fault - Wikipedia
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Fig. 1. Sketch showing a well-developed growth fault and
accompanying structures.
Growth fault
Growth faults are syndepositional or syn-
sedimentary extensional faults that initiate
and evolve at the margins of continental
plates.[1] They extend parallel to passive
margins that have high sediment supply.[2]
Their fault plane dips mostly toward the
basin and has long-term continuous
displacement. Figure one shows a growth
fault with a concave upward fault plane that
has high updip angle and flattened at its
base into zone of detachment or
décollement. This angle is continuously
changing from nearly vertical in the updip
area to nearly horizontal in the downdip
area.
Sedimentary layers have different geometry
and thickness across the fault. The footwall
– landward of the fault plane – has
undisturbed sedimentary strata that dip
gently toward the basin while the hanging wall – on the basin side of the fault plane – has folded
and faulted sedimentary strata that dip landward close to the fault and basinward away from it.[3]
These layers perch on a low density evaporite or over-pressured shale bed that easily flows away
from higher pressure into lower pressure zones.[3] Most studies since the 1990s concentrate on the
growth faults' driving forces, kinematics and accompanied structures since they are helpful in
fossil fuel explorations as they form structural traps for oil.
Growth fault dynamics
Accompanied structures
Driving force
Importance of growth faults
Future work
References
Growth faults maturation is a long term process that takes millions of years with slip rate ranges
between 0.2-1.2 millimeters per year.[4][5] It starts when sedimentary sequences are deposited on
top of each other above a thick evaporite layer (fig. 2).[6] A growth fault is initiated when the
evaporite layer can no longer support the overlying sequences. The thicker and denser portion
applies much more pressure on the evaporite layer than the thin portion.[6] As a result, a flow
within the evaporite layer is initiated from high pressure areas toward low pressure areas causing
Contents
Growth fault dynamics

2. 11/29/21, 5:04 AM Growth fault - Wikipedia
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Figure 2. Sketch showing evolution stages of three growth
faults. The black arrow shows the direction of evolution.
growth ridges to form below the thin
portion. Also, sinking zones are noticed
among these ridges at areas where thicker
and denser layers form(fig. 2).
Consequently, the passive margin
experience unequal subsidence across the
continental shelf.[7] Both the new-created
accommodation spaces and the thickness of
the new-deposited sedimentary layers are
greater above the sinking zones than above
the growth ridges. The new added layers are
thicker within the footwall than within the
hanging wall [7](fig. 2). These variations
result in an increasing of differential load
intensities - unequal distribution of
sediments load - across the shelf with time
as more sediment layers are added(fig. 2).
Therefore, the rate by which the pressure
increases upon the evaporite layer below the
sinking zone are much more than the rate of
pressure increase upon the same evaporite
layer at the growth ridges. So, the flow rate
within the evaporite layer is progressively
increasing as deferential load intensifies(fig.
2). The growth ridges end up with salt
diapir when the sinking zone sequences
weld to the base of the evaporite layer. [1]
As the fault grows upward, it cuts through
the newly formed sedimentary layers at the
top. Therefore, the overall displacement
along the fault plane is not the same.[5]
Further, the lowermost layer has higher
displacement than the uppermost layer
while the intermediate layer displacement lies in between (fig. 2).[1] Because the fault plane
flattens into décollement, the downthrown block moves basinward and the displaced sedimentary
layer of the downthrown block bends close to the fault plane forming rollover anticline, synthetic
and antithetic faults.[7] Figure 3 is an E-W seismic line at Svalbard area showing footwall, hanging
wall and the geometry of sedimentary layers around the fault plane.[8]
Growth faults have two blocks. The upthrown block – the footwall – is landward of the fault plane
and the downthrown block – the hanging wall – is basinward of the fault plane. Most deformations
occur within the hanging wall side. The downthrown block slips downward and basinward relative
to the upthrown block. This is caused due to the differential load of the overlying sediments and
the high mobility of the lowermost low density layer.[7]
As a result, the sedimentary layers collapse forming synthetic and antithetic dip-slip faults that dip
in the same direction or in the opposite direction of the main growth fault respectively or bend
forming rollover anticlines close to the fault plane.[7] Those structures are usually formed
simultaneously and are thought to be created as a result of sediments filling the gap that is formed
Accompanied structures

3. 11/29/21, 5:04 AM Growth fault - Wikipedia
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Fig. 3. Seismic line showing sedimentary layers, footwall and hanging wall of a
growth fault: Modified after Bjerkvik, 2012
hypothetically by the
basinward movement
of the downthrown
block.[9]
The main driving
forces of the growth
faults are the
deferential sediments
load and the low
density layers -
evaporites or over-
pressured shale - that
are formed during or
right after the rifting
process.[10] Growth
faults are located mainly within passive margin sedimentary wedges where tectonic forces have
minimum or no effect. These passive margins receive millions of tons of sediments every year
which are concentrated on the continental shelf below base level and above areas where the water
velocity is no longer supporting the particles weight.[11] This zone is called depositional center
(depocenter for short) and has higher sediments load.
Evaporites and/or high-pressured shale layers have the ability to flow because of their high
mobility and low viscosity characteristics. Rift zones are partially restricted and have limited
access to open oceans during rifting period. they are affected by sea level changes and climatic
variability.[12] Thick layers of evaporites are formed due to continuous water evaporation and fill
of the rift basin.
Shale beds that are deposited during the rift-drift stage have high porosity and low permeability.
This encloses much fluid which under pressure causing the whole shale bed to turn into a viscous,
low density, high mobility layer. The over-pressured shale layers trigger and initiate the growth
faults in the same way as the evaporite layers does.[6]
Earthquakes arise and result from the release of the force along the growth fault plane.[12] The
depocenter's exact location continuously changes because eustatic and relative sea level are
continuously changing as well. As a result, many different growth faults are created as sediment
loads shift basinward and landward.[10]
Growth faults have great significance for stratigraphy, structural geology and the petroleum
industry. They account for relative and eustatic sea level changes and accommodation space left
for new sediments.[1] Likewise, growth faults are connected directly to the subsidence in the
coastal and continental shelf areas.[3][7] Moreover, they explain lateral thickness variation of
sedimentary sequences across these faults.[1] The updip area on the downthrown block is the main
target of oil and gas exploration because it has synthetic and antithetic faults and rollover
anticlines. These are considered as structural traps preventing oil and gas from escaping.[1]
Driving
force
Importance of growth faults

4. 11/29/21, 5:04 AM Growth fault - Wikipedia
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The offset of sand and shale beds occurring along fault planes bring sand and shale layers in
contact to each other. This blocks oil and gas lateral movements and enhances vertical
movements.[1][9] At shallow depths, growth faults and their accompanying synthetic and antithetic
faults are considered as vertical pathways for groundwater to flow and mix between different
groundwater reservoirs.[9] At deeper areas, these conduits help geologists track petroleum
migration up to their final destinations.[1] Oil and gas exploration is usually concentrated very
close to these faults in the downthrown block because these are considered as structural traps
preventing oil and gas from escaping.
Because the growth faults and their accompanied structures control both horizontal and vertical
migration of the underground fluids, most of the current and future studies focus on constructing
three-dimensional models in order to understand geometry and kinematics of these structures.
This will unravel the mystery behind the groundwater contamination due to reservoir mixing, and
track the oil and gas migration pathways.
1. Cazes, C. A.; 2004. "Overlap Zones, Growth Faults, and Sedimentation: Using High
Resolution Gravity Data, Livingston Parish, LA.". Faculty of the Louisiana State University and
Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of
Master of Science in The Department of Geology and Geophysics; Louisiana State University,
Thesis": 147.
2. Schlische, R.W.; Anders, M.H. (1996). "Stratigraphic effects and tectonic implications of the
growth of normal faults and extensional basins. In: Berata, K. (Ed.), Reconstructing the History
of the Basin and Range Extension using Sedimentology and Stratigraphy". Geological Society
of America. 303: 183–203. doi:10.1130/0-8137-2303-5.183 (https://doi.org/10.1130%2F0-8137-
2303-5.183).
3. Doglioni, C.; D’Agostino, N.; Mariotti, G. (1998). "Normal faulting versus regional subsidence
and sedimentation rate". Marine and Petroleum Geology. 15: 737–750. doi:10.1016/s0264-
8172(98)00052-x (https://doi.org/10.1016%2Fs0264-8172%2898%2900052-x).
4. Gagliano, S.M.; Kemp, E.B.; Wicker, K.M.; Wiltenmuth, K.S. (2003). "Active geological faults
and land change in southeastern Louisiana". Prepared for U.S. Army Corps of Engineers, New
Orleans District,. Contract No. DACW 29-00-C-0034.
5. Yeager, K. M.; Brunner C. A.; Kulp, M. A.; Fischer, D.; Feagin e; Schindler K. J.; Prouhet, J.;
Bera, G. (2012). "Significance of active growth faulting on marsh accretion processes in the
lower Pearl River, Louisiana". Geomorphology. 153–154: 127–143.
doi:10.1016/j.geomorph.2012.02.018 (https://doi.org/10.1016%2Fj.geomorph.2012.02.018).
6. Yuill, B.; Lavoie, D.; Reed, D.J. (2009). "Understanding subsidence processes in coastal
Louisiana". Journal of Coastal Research. 10054: 23–36. doi:10.2112/si54-012.1 (https://doi.or
g/10.2112%2Fsi54-012.1).
7. Kuecher, G.J; Roberts H. H; Thompson, M. D.; Matthews, I. (2001). "Evidence for active
growth faulting in the Terrebone delta plain, south Louisiana: implications for wetland loss and
the vertical migration of petroleum". Environmental Geosciences. 2 (8): 77–94.
8. Bjerkvik, A. S. (2012). "Seimic analysis of Carboniferous rift basin and Triassic growth-fault
basins of Svalbard; analysis of seismic facies patterns with bearing on basin geometry and
growth-strata successions (Doctoral dissertation, Norwegian University of Science and
Technology". Earth Sciences and Petroleum Engineering.
9. Losh, S.; Eglinton, L.; Schoell, M.; Wood, J. (1999). "Vertical and lateral fluid flow related to a
large growth fault, South Eugene Island Block 330 Field, offshore Louisiana". American
Association of Petroleum Geologists. 83 (2): 244–276.
Future work
References

5. 11/29/21, 5:04 AM Growth fault - Wikipedia
https://en.wikipedia.org/wiki/Growth_fault 5/5
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10. Verge´s, J.; Marzo, M.; Muñoz, J. A. (2002). "Growth strata in foreland settings". Sedimentary
Geology. 146: 1–9. doi:10.1016/s0037-0738(01)00162-2 (https://doi.org/10.1016%2Fs0037-07
38%2801%2900162-2).
11. Gawthorpe, R.L.; Fraser, A.J.; Collier, R.E.L. (1994). "Sequence stratigraphy in extensional
basins: implications for the interpretation of ancient basin-fills". Marine and Petroleum
Geology. 11: 642–658. doi:10.1016/0264-8172(94)90021-3 (https://doi.org/10.1016%2F0264-8
172%2894%2990021-3).
12. Gawthorpe, R. L.; Leeder, M.R. (2000). "Tectono-sedimentary evolution of active extensional
basins". Basin Research. 12: 195–218. doi:10.1111/j.1365-2117.2000.00121.x (https://doi.org/1
0.1111%2Fj.1365-2117.2000.00121.x).