Lithosphere 1 - the Wilson cycle Flashcards
What did Wilson produce in 1968?
Six-stage Wilson Cycle of opening & closing of basins
What are the three tectonic cycles part of the Wilson cycle?
Ocean opening
Ocean closing
Cratonic
What are the 3 stages of ocean closing on the Wilson cycle?
4- Declining ocean
5- Terminal ocean
6- Continental orogen
What are the 3 stages of ocean opening on the Wilson cycle?
1- embryonic rift
2-Young ocean
3- mature ocean
What are the 2 stages of cratonic on the Wilson cycle?
7- Relic scar/ geosuture
8- Intercratonic sag basin
What is an example of embryonic rift?
Gulf of Suez Egypt
What is an example of young ocean?
Red Sea
What is an example of mature ocean?
Atlantic ocean
What is an example of declining ocean?
Pacific ocean
What is an example of terminal ocean?
Black sea
What is an example of continental orogen?
Indus line in the Himalayas
What is an example of relic scar/ geosuture?
Australia
What is an example of Intracratonic sag basin?
West Siberia Russia
What are the dominant crustal motions and drivers in the embryonic rift?
Rapid basin subsidence (Crustal thinning)
Localised uplift (thermal)
What are the dominant crustal motions and drivers in the young ocean ?
basin subsidence (thermal)
divergence/spreading (ridge push?)
What are the dominant crustal motions and drivers in the mature ocean ?
basin subsidence (thermal)
divergence/spreading (ridge push?)
What are the dominant crustal motions and drivers in the declining ocean ?
Shrinking/subduction
local subsidence (flexure and slab pull?)
What are the dominant crustal motions and drivers in the Terminal ocean ?
Shrinking/subduction
Local uplift (compression)
subsidence (flexure)
What are the dominant crustal motions and drivers in the Continental orogen?
Regional uplift (crustal shortening)
What are the dominant crustal motions and drivers in the relic scar/ geosuture ?
Stable onshore continental setting
What are the dominant crustal motions and drivers in the Intracratonic sag basin ?
Slow/gradual basin Subsidence (thermal?)
What are the Geological and geomorphic
characteristics of embryonic rift?
Rift valleys
What are the Geological and geomorphic
characteristics of young oceans ?
Narrow seaways with central depression
young active spreading ridge
What are the Geological and geomorphic
characteristics of mature ocean?
Large ocean basins with active spreading ridge
What are the Geological and geomorphic
characteristics of declining ocean ?
Island arcs and deep ocean trenches round
ocean margins
What are the Geological and geomorphic
characteristics of ?
What are the Geological and geomorphic
characteristics of terminal ocean?
Young mountains and restricted seaways
What are the Geological and geomorphic
characteristics of Continental orogen?
Young, extensive, high mountains, foreland
basins
What are the Geological and geomorphic
characteristics of Relic scars/ geosuture?
Extensive plains and low relief topography
What are the Geological and geomorphic
characteristics of intracratonic sag basin?
Wide, shallow basins in terrestrial to shallow marine setting
What are the igneous rock types in embryonic rift ?
Tholeitic basalts, alkali basalt centres (hot
spots)
What are the igneous rock types in young ocean?
Tholeiitic basalts (inc. MORB), alkali basalt
centres (hot spots)
What are the igneous rock types in mature ocean?
Tholeiitic basalts (inc. MORB), alkali basalt
centres (hot spots)
What are the igneous rock types in declining ocean?
Andesites, granodiorites at margins
What are the igneous rock types in terminal ocean?
Volcanics, granodiorite at margins
What are the igneous rock types in continental orogen?
Minor
What are the igneous rock types in relic/geosuture ?
Minor
What are the igneous rock types in intracratonic sag basin?
Limited
What are the sedimentary systems within a embryonic rift?
Minor sedimentation,
terrestrial (fluvial, alluvial, lacustrine) to
shallow marine setting
What are the sedimentary systems within a young ocean?
Shelf and basin deposits; evaporites common
What are the sedimentary systems within a mature ocean?
Abundant shelf to deep marine deposits
What are the sedimentary systems within a declining ocean?
Abundant deposits derived from island arcs
What are the sedimentary systems within a terminal ocean?
Abundant deposits derived from island arcs; evaporites possible
What are the sedimentary systems within a continental orogen?
Extensive terrestrial (aeolian red beds) and
marine clastic systems
What are the sedimentary systems within a relic scar/ geosuture?
Terrestrial (aeolian red beds)
What are the sedimentary systems within a intracratonic sag basin?
Regionally extensive sedimentary systems in a Paralic setting
What metamorphism occurs in a embryonic rift?
Negligible
What metamorphism occurs in a young ocean?
Minor (local low grade/thermal)
What metamorphism occurs in a mature ocean?
Minor (local low grade/thermal)
What metamorphism occurs in a declining ocean?
Locally extensive (moderate)
What metamorphism occurs in a terminal ocean?
Locally extensive (moderate -high)
What metamorphism occurs in a continental orogen?
Extensive (high)
What metamorphism occurs in a relic scar/ geosuture?
Minor
What metamorphism occurs in a intracratonic sag basin?
Negligible
What cycle does continental landmass go through?
between super continent and fragmentation
What happens over time to mountains in continental orogen?
exposed to erosional processes
What is a passive margin?
when continental and oceanic crusts meet but arent partaking in any tectonic processes
What can happen to a passive margin?
can become active if denser oceanic plate begins to subduct
What does the subduction oceanic plate promote?
Slab pull as the gravitational force of the plate “pulls” the plate at the mid ocean ridge
What is the flip side of oceanic closing?
Continental assembly
What can cause variations in hydrological and terrestrial ecosystems?
tectonic situation
What is icehouse earth?
Cooler period, continental ice sheets
(lots of collision)
What is greenhouse earth?
warmer period, no continental ice sheets
lots of rifting
