Article ID Journal Published Year Pages File Type
4678892 Earth and Planetary Science Letters 2009 9 Pages PDF
Abstract
We here present results from a series of heated (20 °C, 100 °C, 150 °C) uniaxial consolidation experiments up to effective normal stresses of ca. 70 MPa. The main finding is a positive correlation between temperature and pore space reduction. Based on in-situ temperature information from earlier scientific drilling, our study suggests that temperature has an influence on the consolidation state of underthrust sediments along the Nankai Margin. Together with secondary consolidation, thermal consolidation serves to explain steep log-linear consolidation curves of the incoming Lower Shikoku Basin sediments. The onset of diagenesis in this realm led to the transition of smectite to illite and to a different consolidation behaviour. Estimated in-situ pore pressures based on in-situ temperature data result in up to ∼ 1 MPa smaller overpressures than those previously estimated from drilling data alone. Those values, which imply underconsolidation at drill sites near the frontal Nankai accretionary complex, are further believed to facilitate frictional sliding along the subduction thrust.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth and Planetary Sciences (General)
Authors
, ,