 |
| Titel |
Strain rates of opening-mode fractures in deep basinal settings |
| VerfasserIn |
Peter Eichhübl, John N. Hooker, Andras Fall, Stephen E. Laubach |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035124
|
|
|
|
|
|
| Zusammenfassung |
| Long-term strain rates for geologic processes are characteristically in the range of 10-13 to
10-17 s-1 as measured by a variety of techniques, including geodetic techniques, radiometric
dating of tectonic and structural processes, and through stratigraphic correlations. Here,
we present strain rates for populations of opening-mode fractures in sandstone in
deep basinal settings. Fracture strain is obtained by collecting aperture-frequency
data for microfractures along scanlines in weakly deformed sandstone. Opening
durations of individual macrofractures in the same population are then obtained through
detailed microthermometry of fluid inclusions in crack-seal fracture cement, combined
with textural reconstructions of the fracture opening history. Temperature data are
then correlated with known burial history models to obtain the duration of fracture
opening and the fracture opening strain rate. Individual fractures in deeply buried
sandstone of the East Texas basin, a passive margin setting, opened over 48 m.y. with a
strain rate of 2x10-18 s-1to 5x10-19 s-1. Similar strain rates are obtained for
fractures in the Piceance intermontane basin of Colorado. These ultraslow strain
rates compare well to longterm intraplate seismic strain rates suggesting that rates
of fracture opening are controlled by intraplate tectonic deformation processes. |
|
|
|
|
|
|