1. Kinematics of detachments of
the Chinese margin in Hong
Kong
The University of Hong Kong, Department of Earth Sciences,
Hong Kong
3th March – 31th July 2015
Bibliographical Study
Supervisor: Prof. Lung San ChanIntern: Ugo Nanni
20th February 2015
2. Geographical location
South China Sea
(SCS)
Paleo- South China Sea
(PSCS)
China
Pacific Ocean
IndoChina
N
• Hyper-stretched passive
margin (Vietnam, Iberia)
• Widespread extension (Basins
and Ranges)
Location of study
Chan et al., 2010
Barckhausen et al., 2014
Franke et al., 2013
Taylor and Hayes, 1983
500 km
Bibliographical Study
3. Geographical location
Pearl Delta River zone - Hong Kong geological mapSouth China Sea
(SCS)
Paleo- South China Sea
(PSCS)
China
Pacific Ocean
IndoChina
N
N
• Hyper-stretched passive
margin (Vietnam, Iberia)
• Widespread extension (Basins
and Ranges)
Location of study
Chan et al., 2010
Barckhausen et al., 2014
Franke et al., 2013
Taylor and Hayes, 1983
500 km
10 km
Bibliographical Study
4. Geographical location
Hong Kong geological map
(SCS)
(PSCS)
China
Pacific Ocean
IndoChina
N
N
Chan et al., 2010
Barckhausen et al., 2014
Franke et al., 2013
Taylor and Hayes, 1983
Collapsed cretaceous belt
Very stretched crust
Oceanic crust
• Hyper-stretched passive
margin
Location of study
500 km
10 km
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5. Transition Ocean-Continent
Schematic evolution of a traditional passive
margin
Upper mantle
Lower crust
Upper crust
Stretching Thinning Exhumation C.O
Savva et al., 2013
Manatschal et ., 2004
Cretaceous
syn-extension
Spatial and chronological evolution
30km
5km
- Different
mechanical
behaviour
- SCS: hyper-
thinned margin
Detachement
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6. Structural heritage and physical boundaries:
driving the extension
Mantle
Lower crust
Upper crust
NNW SSE
Hong Kong
Savva et al., 2013
Sliding along granite
Cretaceous
syn-extension
(molasse)
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7. Field observation:
Late cretaceous deposits
• Redbeds: calcareous breccia,
conglomerate, deposit during
cretaceous extension
Onshore, Red beds Kat O formation,
Hong Kong
• Very little deformation
Miki et al., 1990
Civil Engineering and Development
Department (HKSAR)
Lai et al., 1996
Bibliographical Study
8. Offshore, seismic line
• Redbeds: molasse
• Brittle deformation
(extension)
But …
Savva et al., 2013
(SCS)
N
Late Cretaceous
Pliocene
Miocene
Paleogene
BasementCretaceous
Field observation:
Late cretaceous deposits
Bibliographical Study
9. • Ductile deformation in the red beds:
1mm
- Level of stretched pebbles on a
detachment
Courtesy of M.Pubellier
- Stretched pebble
- Thin section of a
cataclasite
between pebbles
Field observation:
Late cretaceous deposits
15 m
Bibliographical Study
"authigenic muscovite and pressure solution shadows of minerals are observed"
Mikki et al., 1990
10. • Ductile deformation in the red beds:
1mm
- Level of stretched pebbles on a
detachment
Courtesy of M.Pubellier
- Stretched pebble
- Thin section of a
cataclasite
between pebbles
Field observation:
Late cretaceous deposits
15 m
Bibliographical Study
"authigenic muscovite and pressure solution shadows of minerals are observed"
Mikki et al., 1990
11. • Ductile deformation in the red beds:
Courtesy of M.Pubellier
- Stretched pebble
Field observation:
Late cretaceous deposits
Hong Kong geological map
N
Tai po
-North to South thrust
2.5 km
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1mm
- Thin section of a
cataclasite
between pebbles
"authigenic muscovite and pressure solution shadows of minerals are observed"
Mikki et al., 1990
12. Structural study of sheared pebbles
1. Field mapping and sampling :
- Characterization of the contact and its geometry
- Delimitation of the area
- Sampling (statistic)
2. Laboratory experiment:
- To determine sense of motion from microstructures (thin sections, )
- To determine the style of deformation
- What mechanism of deformation ?
Link(s) between sheared
pebbles and red beds ?
ISTeP
Bibliographical Study
13. Datation methods
Spontaneous
desintegration
of 238U
Under Tclosure
T° - z
40K 40Ar*
Datation
Exhumation rate
Fission Tracks K-Ar
Modelisation
Glotzbach et al., 2011
Rolland et al., 2008
Seward and Mancktelow, 1994
Bibliographical Study
14. 1. K-Ar dating :
- Collection of samples of micas within the shear zone
2. Fission tracks (FT) :
- Compilation of data (ENS-HKU), working with Xuran Zuo (HKU)
- Calculation of granite exhumation rate (rift shoulders, uplift)
- Estimation of the bassins dynamic
Temporal study of sheared pebbles and exhumation
Datation of the
shear zone
Link with the
structure
FT data: Pubellier, Savva, Chan, Zuo
Bibliographical Study
15. Hypothesis and expected results
Sheared pebbles,
deformation
Extension or
compression ?
Simple shear or
pure shear ?
Timing ?
Spatial
distribution ?
Kinematic ?
• Hyper-stretched
passive margin
• Cretaceous sedimentation
during extension
Bibliographical Study
16. Hypothesis and expected results
Sheared pebbles,
deformation
NNW SSE
?
Extension or
compression ?
Simple shear or
pure shear ?
Timing ?
Spatial
distribution ?
Kinematic ?
Bibliographical Study
17. Sheared pebbles,
deformation
Extension or
compression ?
Simple shear or
pure shear ?
Timing ?
Spatial
distribution ?
?
Mantle
Lower crust
Upper crust
Hypothesis and expected results
Kinematic ?
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18. Sheared pebbles
deformation
?
Hypothesis and expected results
Orogenic collapse Triggering of rifting
Extension or
compression ?
Simple shear or
pure shear ?
Timing ?
Spatial
distribution ?
Kinematic ?
Bibliographical Study
19. Bibliography
Barckhausen, U., Engels, M., Franke, D., Ladage, S., Pubellier, M., 2014. Evolution of the South China Sea: revised
ages for breakup and seafloor spreading. Mar. Petrol. Geol..
Chan, L.S., Shen, W., Pubellier, M., 2010. Polyphase rifting of greater Pearl River Delta region (South China):
evidence for possible rapid changes in regional stress configuration. J. Struct. Geol. 32, 746e754.
Franke, D., Savva, D., Pubellier, M., Meresse, F., Steuer, S., Auxietre, 2013. The final rifting evolution in the South
China Sea. In: Pubellier, M., McIntosh, K.,
Glotzbach, C., van der Beek, P. a. and Spiegel, C., 2011. Episodic exhumation and relief growth in the Mont Blanc
massif, Western Alps from numerical modelling of thermochronology data: Earth and Planetary Science Letters, 304,
p. 417–430, doi: 10.1016/j.epsl.2011.02.020.
Hayes, D., Nissen, S., 2005. The South China Sea margins: implication for rifting contrast. Earth Planet. Sci. Lett. 237,
601e616.
Rolland, Y., Rossi, M., Cox, S.F., Corsini, M., Mancktelow, N.S., Pennacchioni, G., Fornari, M. and Boullier, A., 2008.
40Ar/39Ar dating of synkinematic white mica: insights from fluid-rock reaction in low-grade shear zones (Mont Blanc
Massif) and constraints on timing of deformation in the NW external Alps: Geological Society, London, Special
Publications, 299, p. 293–315, doi: 10.1144/SP299.18.
Bibliographical Study
20. Bibliography
Manatschal, G., 2004. New models for evolution of magma-poor rifted margins based on a review of data and
concepts from West Iberia and the Alps. Int. J.Earth Sci. 93, 432e466.
Miki, T., Matsueda, H., & Yim, W. W. S. (1990). Petrography and geochemistry of Cretaceous (?) red beds in
Hong Kong. Journal of Southeast Asian Earth Sciences, 4(2), 99-106.
Pubellier, M., Chan, L.S., 2006. Structural Map of Cenozoïc Structures of South China and North Vietnam
Coastal. CGMW.
Pubellier, personal contribution
Savva, D., Meresse, F., Pubellier, M., Chamot-Rooke, N., Lavier, L., Wong Po, K.,Franke, D., Steuer, S.,
Sapin, F., Auxietre, J.L., Lamy, G., 2013. Seismic evidences of hyper-stretched crust and mantle exhumation
offshore Vietnam. Tectonophsics .
Seward, D. and Mancktelow, N.S., 1994. Neogene kinematics of the central and western Alps : Evidence from
fission-track dating: Geology, 22, p. 803–806, doi: 10.1130/0091-7613(1994)022<0803:NKOTCA>2.3.CO;2.
Taylor, B., Hayes, D.E., 1983. Origin and history of the South China Basin. In: Hayes, D.E. (Ed.), The Tectonic
and Geologic Evolution of Southeast Asian Seas and Islands, Part 2, Geophys. Monogr. Ser, vol. 27. AGU,
Washington, D.C, pp. 23e56.
Bibliographical Study
22. A brief history of the South China Sea (SCS)
Late Cretaceous -
Late Eocene
Early Oligocene -
Late Oligocene
Early Miocene -
Early Pliocene
Middle Jurassic to Middle Cretaceous: Andean type of volcanic arc
ConvergenceExtension
From Savva et al., 2013
Synrift- sedimentation
Passive margin
Transition orogenic collapse - rifting Slab- pull
Bibliographical Study
23. Stretched pebble
from the tanaron
unit (under la Nappe
de Dignes)
L.Jolivet, M.MoroniBibliographical Study
