| 1. |
|
|
| 2. |
|
|
| 3. |
- Bahroudi, A, et al.
(författare)
-
Effect of ductile and frictional decollements on style of extension
- 2003
-
Ingår i: Journal of Structural Geology. - 0191-8141 .- 1873-1201. ; 25:9, s. 1401-1423
-
Tidskriftsartikel (refereegranskat)abstract
- Scaled analogue models were used to study the effect of frictional and ductile detachments on thin-skinned extension. Models consisted of two halves; one half is the ductile and the other has a frictional detachment. Extension occurred above two different basal configurations: a stretchable rubber sheet and a folded, banded sheet intended to produce homogeneous and heterogeneous extension, respectively. Model parameters varied systematically and included the brittle/ductile thickness ratio, rheologies, and bulk strain. Structures in the two halves are compared in profiles and plan views. A series of graben developed above both halves of models extended above a banded sheet, although there were differences in style, propagation rate and width of the deformation zone between the two halves. Different rates of propagation of structures in the two halves led to the formation of an accommodation or transfer zone parallel to the extension direction. Most relay ramps and inflection of normal faults in this zone indicate differential extension between the two halves.In contrast, in models extended above a stretchable rubber sheet, extensional structures such as horst and graben developed only above the ductile detachment. Model results indicate that heterogeneous mechanical stratigraphy and displacement rate have no effect on extensional structure above a rubber sheet. However, above 20% bulk extension, deformation becomes heterogeneous along multiple sets of conjugate faults oblique to the extension direction.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Hessami, Khaled, et al.
(författare)
-
Progressive unconformities within an evolving foreland fold-thrust belt, Zagros Mountains.
- 2001
-
Ingår i: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 158:6, s. 969-981
-
Tidskriftsartikel (refereegranskat)abstract
- A major angular unconformity between the Bakhtyari conglomerates and the underlying Agha Jari Formation has long been interpreted as indicating that orogeny in the Zagros Simply Folded Zone took place in Plio-Pleistocene times. This study uses field evidence of unconformities between older units in conjunction with geological maps and cross sections to argue that the front of the Zagros Simply Folded Zone has propagated in time and space. These unconformities indicate that deformation started as early as end Eocene in the northeast of the Simply Folded Zone and propagated progressively to the southwest, where unconformable contacts are only seen between younger units. As shortening continued, the southwest migration of the deformation front drove the foreland basin in front of it to its present position along the Persian Gulf and Mesopotamia. The climax of orogeny took place at end Pliocene time when the most extensive unconformity in the Zagros Simply Folded Zone developed between the (upper) Bakhtyari Formation and older units. Active seismicity and documented present uplift imply that the Simply Folded Zone is still propagating southwestward.
|
|
| 7. |
|
|
| 8. |
- Langer, M., et al.
(författare)
-
Editors introduction to special issue on geosciences and nuclear waste isolation.
- 2001
-
Ingår i: Engineering Geology. - 0013-7952. ; 61, s. 69-73
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Crustal roots formed beneath mountain belts are gravitationally unstable structures, which rebound when the lateral forces that created them cease or decrease significantly relative to gravity. Crustal roots do not rebound as a rigid body, but undergo int
|
|
| 9. |
- Pan, M., et al.
(författare)
-
Crustal movements in Skane, Sweden, between 1992 and 1998 as observed by GPS
- 2001
-
Ingår i: Journal of Geodynamics. - 0264-3707 .- 1879-1670. ; 31:3, s. 311-322
-
Tidskriftsartikel (refereegranskat)abstract
- We estimate a network of crustal deformations in Skane, southern Sweden, using observations of the Global Positioning System (GPS) from 1992, 1996 and 1998. The network straddles the Tornquist zone, potentially one of the most active fault zones in Sweden. In addition to two stations of the Swedish permanent GPS network (Onsala and Hassleholm), it includes seven GPS sites spaced approximately 80 km apart. The precisions of the relative horizontal components for these stations are described by repeatabilities with approximately 3 mm in the north-south direction and about 2 mm in the east-west direction in the campaigns in the reference frame ITRF96. About 70% of the GPS integer carrier phase ambiguities were resolved for the three campaigns. Three stations south of the Tornquist zone moved with a rate of 5+/-0.2 mm/a toward the SW-SE, and two other stations further to the east with a rate of 2+/-0.2 mm/a toward the SE, relative to station Onsala. The displacements mean that a lateral strike-slip transtensional fault exists within the Tornquist zone, and the relative motion between the two sides along the zone was about 2 mm/a. The old fault is still active, which is consistent with geological results. The station Stavershult closest to Onsala moved NE with about 1.5+/-0.8 mm/a relative to the station Onsala. This may imply a transtensional fault between Stavershult and Onsala. If we assume that Stavershult represents the Baltic shield, Onsala has moved 1.5 mm/a toward the southwest with respect to the Baltic shield, which was confirmed by data of Very Long Baseline Interferometry (VLBI) and Satellite Laser Ranging (SLR) from 1976 to 1997 (Argus, D.F., Peltier, W.R., Watkins, M.M. Glacial isostatic adjustment observed by Very Long Baseline Interferometry and Satellite Laser Ranging geodesy. JGR 1999;104(B12);29077-93).
|
|
| 10. |
- Sokoutis, Dimitrios, et al.
(författare)
-
Indentation of a continent with a built-in thickness change : experiment and nature
- 2000
-
Ingår i: Tectonophysics. - 0040-1951 .- 1879-3266. ; 320:3-4, s. 243-270
-
Tidskriftsartikel (refereegranskat)abstract
- Orogens oblique to the direction of plate convergence are currently attributed to obliquity between the margins of one or both of the sutured continents to their direction convergence. We use a single analogue experiment and natural examples to illustrate a potential additional factor: variations in strength of the indented continent at a high angle to the convergence direction. The wavelengths of structures in laterally shortened lithosphere depend on the strength of the most competent layers. Lateral variations in crustal thickness must therefore lead to structures oblique to any applied lateral compression.An analogue experiment was performed to explore this phenomenon. A two-layer ‘indented continent’ was modelled by a brittle upper crust of sand above a lower crust of high-viscosity polymer floating on a single layer of low-viscosity syrup representing the mantle. The well-known strike-slip structures allowing lateral escape to distant weak boundaries were hindered by lateral boundaries in front of the indenter. This allowed us to focus on the effects of a thickness change built into the ‘indented continent’ along a zone parallel to the direction in which a vertical rigid wall advancing at a steady rate represented the indenter. Vertical escape led to an ‘orogenic belt’ oblique to the advancing wall; this obliquity influences subsequent lateral escape. Model scaling and interpretations are based on Extended Thin Sheet Approximation (ETSA) and standard theories of faulting.Four sectors of the Alpine–Himalayan orogen (Iran, Tunisia, the Eastern Alps and the Himalaya) are oblique to the continental convergence direction, and we point to thickness changes at high angles to the suture that may account for this geometry. As crustal thicknesses north of oblique sectors of the Himalayas are not yet known, we speculate on them.We infer from the main difference between our experiment and all our examples chosen from nature that vertical orogenic escape was oblique to our model suture but can be parallel to natural sutures.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
- Talbot, C. J.
(författare)
-
Weak zones in Precambrian Sweden
- 2001
-
Ingår i: Geological Society, London, Special Publications. ; 186, s. 287-304
-
Tidskriftsartikel (refereegranskat)
|
|
| 18. |
- Tunlid, Anders, et al.
(författare)
-
Genomics of parasitic and symbiotic fungi
- 2002
-
Ingår i: Current Opinion in Microbiology. - 1879-0364. ; 5:5, s. 513-519
-
Forskningsöversikt (refereegranskat)abstract
- Complete and partial genome sequence information is underway in several parasitic and symbiotic fungi that infect humans, other animals and plants. Comparative analyses of these sequences will provide new insights into the genomic plasticity and evolution of parasitism and mutualism in fungi.
|
|
| 19. |
|
|
