AAPG/GSTT HEDBERG CONFERENCE
“Mobile
Shale Basins – Genesis, Evolution and Hydrocarbon Systems”
Clastic injectites: a comparative analysis of
mud, sand and conglomerate injectites
Mads Huuse1,
Richard J. Davies2, Steve Hubbard3, Joe A. Cartwright4,
Andrew Hurst1
1Department of Geology and Petroleum Geology,
2Department of Earth Sciences,
3School of Earth Sciences,
43Dlab,
Clastic injectites are a long-recognized but
enigmatic type of geological structure straddling the fields of sedimentary and
structural geology. They form by post-depositional remobilization and injection
of clastic sediments and comprise remobilised, diapiric and injected masses of mud, sand, or,
occasionally, conglomerate. Here, we show examples of deca-
to hundred-metre scale mud, sand and conglomerate injectites in outcrop and km-scale mud and sand injectites seen in seismic data. Our comparative analysis
serves to highlight their common occurrence, their similarities and differences
in terms of geometries, fill and geological context in terms of: tectonic
setting, host rock lithology, depth of burial of the injectite
source bed(s), the (inferred) pressure conditions and absence or presence of
hydrocarbons at the time of injection. A global database of observations would
suggest that mud injections are more common in compressional settings, whilst
sand injectites dominantly occur in deepwater slope
and basin settings along relatively passive margins.
AAPG Search and Discovery Article #90057©2006 AAPG/GSTT Hedberg Conference, Port of Spain, Trinidad & Tobago