Hydrocarbon generation-a possible cause of elevated pore pressures in the Osen-Roa thrust sheet, Norway
1992; Elsevier BV; Volume: 14; Issue: 6 Linguagem: Inglês
10.1016/0191-8141(92)90131-f
ISSN1873-1201
Autores Tópico(s)Geological Studies and Exploration
ResumoThe Osen-Roa thrust is very large (275 km wide in the thrust transport direction), thin (1–4 km thick) and internally shortened by 270 km. Over much of its extent the thrust sheet has moved over autochthonous or para-autochthonous Alum Shales (Cambrian). Such a large and thin thrust sheet is difficult to move as a coherent unit. High pore-fluid pressures are commonly invoked to help explain such problems. The Alum Shales are very rich in organic carbon (5–20 weight percent). They are capable of generating large volumes of hydrocarbons which could have periodically caused elevated pore-fluid pressures. The first event that was likely to have buried the Alum Shales to oil-generating depths was overthrusting during the Caledonian orogeny. Consequently, overpressuring in the Alum Shales due to hydrocarbon generation may help to explain the size of the Osen-Roa thrust sheet.
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