AAPG/GSTT HEDBERG CONFERENCE
“Mobile Shale Basins – Genesis, Evolution and Hydrocarbon Systems”
Turtles structures created by extension in a thin detachment setting
Joshua Creviere Turner
structures are generally regarded to be the result of passive or extensional
collapse of underlying salt bodies.
However subsurface examples, in the
I propose the term extensional turtles to denote a class of turtle structures at the opposite end of the spectrum from traditional turtles where a mock turtle lies between. Extensional turtles are generated purely by extension, unlike mock turtles. Even so, they commonly have some mobile-rock withdrawal, as they are always associated with a very weak detachment. The distinguishing feature of such structures is that they are bound by a kinematically linked set of regional and counter-regional large-offset listric normal faults. Local complications may occur where younger regional faults repeatedly cut the counter-regional fault, resulting in the counter-regional fault becoming reset down-dip. The counter-regional fault may then remain active, resulting in multiple turtle anticlines. Counter-regional rollover followed by regional rollover on opposing arcuate listric faults produces four-way plunging turtles.
AAPG Search and Discovery Article #90057©2006 AAPG/GSTT Hedberg Conference, Port of Spain, Trinidad & Tobago