Models of passive margin inversion: implications for the Rhenohercynian fold-and-thrust belt, Belgium and Germany

Abstract. Foreland fold-and-thrust belts (FTBs) record long-lived tectono-sedimentary activity, from passive margin sedimentation, flexuring, and further evolution into wedge accretion ahead of an advancing orogen. Therefore, dating fault activity is fundamental for plate movement reconstruction, resource exploration, and earthquake hazard assessment. Here, we report U–Pb ages of syn-tectonic calcite mineralizations from four thrusts and three tear faults sampled at the regional scale across the Jura fold-and-thrust belt in the northwestern Alpine foreland (eastern France). Three regional tectonic phases are recognized in the middle Eocene–Pliocene interval: (1) pre-orogenic faulting at 48.4±1.5 and 44.7±2.6 Ma associated with the far-field effect of the Alpine or Pyrenean compression, (2) syn-orogenic thrusting at 11.4±1.1, 10.6±0.5, 9.7±1.4, 9.6±0.3, and 7.5±1.1 Ma associated with the formation of the Jura fold-and-thrust belt with possible in-sequence thrust propagation, and (3) syn-orogenic tear faulting at 10.5±0.4, 9.1±6.5, 5.7±4.7, and at 4.8±1.7 Ma including the reactivation of a pre-orogenic fault at 3.9±2.9 Ma. Previously unknown faulting events at 48.4±1.5 and 44.7±2.6 Ma predate the reported late Eocene age for tectonic activity onset in the Alpine foreland by ∼10 Myr. In addition, we date the previously inferred reactivation of pre-orogenic strike-slip faults as tear faults during Jura imbrication. The U–Pb ages document a minimal time frame for the evolution of the Jura FTB wedge by possible in-sequence thrust imbrication above the low-friction basal decollement consisting of evaporites.

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Controls on the evolution of passive-margin salt basins: Structure and evolution of the Salina del Bravo region, northeastern Mexico

Geological Society of America Bulletin ◽

10.1130/b35283.1 ◽

2019 ◽

Vol 132 (5-6) ◽

pp. 997-1012 ◽

Cited By ~ 3

Author(s):

Michael R. Hudec ◽

Tim P. Dooley ◽

Frank J. Peel ◽

Juan I. Soto

Keyword(s):

Seismic Data ◽

Passive Margin ◽

Salt Tectonics ◽

Structural Systems ◽

Thrust Belt ◽

Entire Region ◽

Fold And Thrust Belt ◽

Gravity Driven ◽

Northeastern Mexico ◽

Uplift History

Abstract Passive-margin salt basins tend to be much more deformed than their nonsalt equivalents, but they are by no means all the same. We used seismic data to study the Salina del Bravo region, northeast Mexico, to investigate the ways in which margin configuration and postsalt uplift history can influence passive-margin salt tectonics. The Salina del Bravo area contains four main structural systems, all of which trend NNE across the entire region. These structures are the Bravo trough, Sigsbee salt canopy, Perdido fold-and-thrust belt, and BAHA high. Gravity-driven deformation did not begin until more than 130 m.y. after salt deposition, because of buttressing against the BAHA high. We suggest that deformation was ultimately triggered in the Cenozoic by Cordilleran uplift that tilted the margin seaward and created a major sediment source terrane. Sediments shed from the uplift expelled salt seaward to form the Sigsbee canopy. At the same time, tilted and loaded sediments were translated seaward on the Louann salt until they were buttressed against the BAHA high, forming the Perdido fold-and-thrust belt. A physical model was built to test this hypothesis. The model was able to reproduce most of the major structures in the region, suggesting that the hypothesis is reasonable. The Salina del Bravo region shows how a downdip buttress can inhibit gravity-driven salt deformation in passive-margin salt basins. Furthermore, the area also shows the importance of postsalt uplift, which can destabilize a margin through a combination of tilting and sedimentation.

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Accretion of a rifted passive margin: The Late Paleozoic Rhenohercynian fold and thrust belt (Middle European Variscides)

Tectonics ◽

10.1029/98tc02763 ◽

1999 ◽

Vol 18 (1) ◽

pp. 75-91 ◽

Cited By ~ 95

Author(s):

O. Oncken ◽

C. von Winterfeld ◽

U. Dittmar

Keyword(s):

Passive Margin ◽

Late Paleozoic ◽

Thrust Belt ◽

Fold And Thrust Belt ◽

European Variscides

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The Lamu Basin deepwater fold-and-thrust belt: An example of a margin-scale, gravity-driven thrust belt along the continental passive margin of East Africa

Tectonics ◽

10.1002/2015tc003856 ◽

2016 ◽

Vol 35 (3) ◽

pp. 491-510 ◽

Cited By ~ 9

Author(s):

Francesco Cruciani ◽

Massimiliano R. Barchi

Keyword(s):

East Africa ◽

Passive Margin ◽

Thrust Belt ◽

Fold And Thrust Belt ◽

Gravity Driven

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The Franklinian Composite Tectono-Sedimentary Element, North Greenland

Geological Society London Memoirs ◽

10.1144/m57-2020-6 ◽

2021 ◽

pp. M57-2020-6

Author(s):

John R. Hopper ◽

Jon R. Ineson

Keyword(s):

Heat Flow ◽

Passive Margin ◽

Thrust Belt ◽

Reservoir Properties ◽

Good Source ◽

Petroleum Potential ◽

The North ◽

Fold And Thrust Belt ◽

North Greenland ◽

Mixed Carbonate

AbstractThe Franklinian margin composite tectono-sedimentary element (CTSE) in North Greenland is dominated by Neoproterozoic - lowermost Devonian sedimentary strata that include early syn-rift through passive margin TSEs of mixed carbonate and siliciclastic facies. The sedimentary successions are well exposed in much of northern Greenland, but locally were strongly affected by the Ellesmerian Orogeny, resulting in a fold and thrust belt that deformed the northernmost exposures. An exposed palaeo-oilfield attests to the petroleum potential of the basin. Several formations have good source potential and several others have good reservoir properties. Palaeo-heat flow indicators show that temperatures increase to the north, where much of the basin is over-mature. Because of the remoteness of the area and the restricted locations where petroleum potential is likely to remain, the basin is not currently a target for exploration.

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Mid-crustal detachment beneath southern Timor-Leste: seismic evidence for Australian basement in the Timor collision complex (and implications for prospectivity)

10.29118/ipa21-g-98 ◽

2021 ◽

Author(s):

T. R. Charlton

Keyword(s):

Seismic Data ◽

Passive Margin ◽

Petroleum Exploration ◽

Seismic Survey ◽

Normal Faults ◽

Thrust Belt ◽

Collision Complex ◽

Fold And Thrust Belt ◽

Timor Leste ◽

Seismic Sections

Seismic data originally acquired over SW Timor-Leste in 1994 shows two consistent seismic reflectors mappable across the study area. The shallower ‘red’ reflector (0.4-1s twt) deepens southward, although with a block-faulted morphology. The normal faults cutting the red marker tend to merge downward into the deeper ‘blue’ marker horizon (0.5-2.8s twt), which also deepens southward. Drilling intersections in the Matai petroleum exploration wells demonstrate that the red marker horizon corresponds to the top of metamorphic basement (Lolotoi Complex), while the blue marker horizon has the geometry of a mid-crustal extensional detachment. We see no indications for thrusting on the seismic sections below the red marker horizon, consistent with studies of the Lolotoi Complex at outcrop. However, surficial geology over much of the seismic survey area comprises a thin-skinned fold and thrust belt, established in 8 wells to overlie the Lolotoi Complex. We interpret the fold and thrust belt as the primary expression of Neogene arc-continent collisional orogeny, while the Lolotoi Complex represents Australian continental basement underthrust beneath the collision complex. In the seismic data the basal décollement to the thrust belt dips southward beneath the synorogenic Suai Basin on the south coast of Timor, and presumably continues southward beneath the offshore fold and thrust belt, linking into the northward-dipping décollement that emerges at the Timor Trough deformation front. The same seismic dataset has been interpreted by Bucknill et al. (2019) in terms of emplacement of an Asian allochthon on top of an imbricated Australian passive margin succession. These authors further interpreted a subthrust anticlinal exploration prospect beneath the allochthon, which Timor Resources plan to drill in 2021. This well (Lafaek) will have enormous significance not only commercially, but potentially also in resolving the long-standing allochthon controversy in Timor: i.e., does the Lolotoi Complex represent ‘Australian’ or ‘Asian’ basement?

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