Slope failure of chalk channel margins: implications of an Upper Cretaceous mass transport complex, southern England
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Slope failure of chalk channel margins : implications of an Upper Cretaceous mass transport complex, southern England. / Gale, A.; Anderskouv, Kresten; Surlyk, Finn; Whalley, J. .
I: Journal of the Geological Society., Bind 172, 2015, s. 763–776.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Slope failure of chalk channel margins
T2 - implications of an Upper Cretaceous mass transport complex, southern England
AU - Gale, A.
AU - Anderskouv, Kresten
AU - Surlyk, Finn
AU - Whalley, J.
PY - 2015
Y1 - 2015
N2 - The importance of mass transport and bottom currents is now widely recognized in the Upper Cretaceous Chalk Group of Northern Europe. The detailed dynamics and interaction of the two phenomena are difficult to study as most evidence is based on seismic data and drill core. Here, field observations provide evidence for recurring margin collapse of a long-lived Campanian channel. Compressionally deformed and thrust chalk hardgrounds are correlated to thicker, non-cemented chalk beds that form a broad, gentle anticline. These chalks represent a slump complex with a roll-over anticline of expanded, non-cemented chalk in the head region and a culmination of condensed hardgrounds in the toe region. Observations strongly suggest that the slumping represents collapse of a channel margin. Farther northwards, the contemporaneous succession shows evidence of small-scale penecontemporaneous normal faulting towards the south, here interpreted as gravitational settling of the chalk immediately adjacent to the channel margin. Detailed biostratigraphic studies and sedimentological observations provide evidence for at least two discrete collapse events and suggest the slumping to be the result of channel margin oversteepening rather than evidence for a regional tectonic phase. The described example thus serves as an analogue for processes commonly only inferred from subsurface data.
AB - The importance of mass transport and bottom currents is now widely recognized in the Upper Cretaceous Chalk Group of Northern Europe. The detailed dynamics and interaction of the two phenomena are difficult to study as most evidence is based on seismic data and drill core. Here, field observations provide evidence for recurring margin collapse of a long-lived Campanian channel. Compressionally deformed and thrust chalk hardgrounds are correlated to thicker, non-cemented chalk beds that form a broad, gentle anticline. These chalks represent a slump complex with a roll-over anticline of expanded, non-cemented chalk in the head region and a culmination of condensed hardgrounds in the toe region. Observations strongly suggest that the slumping represents collapse of a channel margin. Farther northwards, the contemporaneous succession shows evidence of small-scale penecontemporaneous normal faulting towards the south, here interpreted as gravitational settling of the chalk immediately adjacent to the channel margin. Detailed biostratigraphic studies and sedimentological observations provide evidence for at least two discrete collapse events and suggest the slumping to be the result of channel margin oversteepening rather than evidence for a regional tectonic phase. The described example thus serves as an analogue for processes commonly only inferred from subsurface data.
U2 - 10.1144/jgs2014-124
DO - 10.1144/jgs2014-124
M3 - Journal article
VL - 172
SP - 763
EP - 776
JO - Journal of the Geological Society
JF - Journal of the Geological Society
SN - 0016-7649
ER -
ID: 160614906