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4.2 Plio-Quat of W Cyprus (Miocene-Pliocene boundary (Unconformity btwn…
4.2
Plio-Quat of W Cyprus
W Flank
Polis Graben
Brow of hill after Kathikas
3 fault blocks
Beds dip increasingly toward Polis Graben moving E
hilltops = displaced downward moving E
Limestone
Interp:
Backtilting of a half graben by normal faulting
From W to E:
Block 1:
Horiz bedding
Block 2: Dipping into block 1 (W)
Block 3: Dips toward Polis Graben
(forward dipping fault block)
Polis Graben
(ANYA)
Comprises 2 structures
2 phases of faulting due to crustal extension
E Polis Graben
Formed: Late Miocene
Driver: Plate boundary btwn Turkish & Arab plates
Pegeia
Half-Graben
Formed: Plio-Quat
Synthetic faulting
NNW - SSE ∴ dips into Polis Graben
After Quaternary - faulting diminished
Graben
= asymmetrical trending NW-SE
terminates @ transform to South
Faulting on 3 scales
Grabens
Steep fault
one fault block can move down without much def
no space problem
faulting accomodates downward motion
fault block can rotate into graben
Lower
angle fault
Space problem arises
Footwall constrains hanging wall
as h.w. moves down
What happens?
H.W. drags along fault
Syncline forms @ fault as beds near fault plane = buckled down
Tight syncline beside fault
Wider implications
Large anticlinal structure formed 'rollover anticline'
as a result of localised space problem
E Flank Polis Graben
= characterised by rollover structures
Evretou Dam
Miocene-Pliocene boundary
Marine - non-marine boundary
Non marine conglom (Messinian ~5Ma)
Calcarenite (Tortonian)
Marl (Pliocene ~2Ma)
Unconformity btwn Messinian & Tortonian
~ 3 Ma gap
Shows it took a while for sealevel to rise up to reach flanks
∴ took 3 Ma to go from Messinian to Pliocene rocks
Messinian non-marine facies unconformably overlie Tortonian calcarenite
Faulted block creates space for infill
Pliocene calcturbidites infill the graben
Well bedded marl beneath?
Calcarenite ~1.6-1.7 Ma
= last marine deposit
Polis Graben Age
= Neotectonic graben
Faulting from L. Miocene -> Present
Oldest on flanks
Youngest sediments in centre
Slab rollback creates new accom space in supra SZ areas