Magnetic fabric of a basaltic dyke swarm associated with Mesozoic rifting in northeastern Brazil

Archanjo, Carlos José; Trindade, R. I.; Macedo, J.W.P.; Araújo, Marcelus G

doi:10.1016/s0895-9811(00)00023-7

Cited by 40 publications

(28 citation statements)

References 24 publications

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“…The kinematics of lava emplacement recorded in the solidified rock as foliation and lineation, gives information on the end of fabric history (Fernandez and Laporte, 1991) and flow direction in dikes (Archanjo et al, 2000). Dike emplacement in a given tectonic setting has to record differential stress involving the combined effect of both external and internal stress fields (Correa-Gomes et al, 2001).…”

Section: Kinematics Of Lava Flowmentioning

confidence: 99%

Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Féménias

Diot

Berza

et al. 2004

Journal of Structural Geology

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Section: Kinematics Of Lava Flowmentioning

confidence: 99%

Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Féménias

Diot

Berza

et al. 2004

Journal of Structural Geology

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“…Determining magmatransport directions in dykes and/or sills is one of the most important steps forward in our under standing of magmatic plumbing systems. There are several case studies exhibiting this application (Rochette et al 1991, Archanjo et al 2000, Herrero-Berrera et al 2001, Gil et al 2002.…”

Section: Dykes and Sillsmentioning

confidence: 99%

“…the flow plane and/or direc tion, of these rocks has been demonstrated in volcanic formations throughout the world (e.g. Dragoni et al 1997, Le Pennée et al 1998, Smith 1998, Varga et al 1998, Archanjo et al 2000, Canon-Tapia & Pinkerton 2000. The method favours great acceptance because: it exhibits high sensitivity, is non time-consuming and can be applied to a variety of formations -lava flows, pyroclastic deposits, ash and tuff flows, ignimbrites, sills and dykes.…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of Magnetic Susceptibility (Ams) in Volcanic Formations: Theory and Preliminary Results From Recent Volcanics of Broader Aegean.

Zananiri

Kondopoulou

2004

geosociety

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The anisotropy of magnetic susceptibility (AMS) is a physical property of rocks widely used in petrofabric studies and other applications. It is based on the measurement of low-field magnetic susceptibility in different directions along a sample. From this process several scalar properties arise, defining the magnitude and symmetry of the AMS ellipsoid, along with the magnetic foliation, namely the magnetic fabric. Imaging the sense of magma flow in dykes is an important task for volcanology; the magnetic fabric provides a fast and accurate way to infer this flow direction. Moreover, the AMS technique can be used in order to distinguish sills and dykes, a task that is almost impossible by using only field observations. Finally in the case of lava flows, the method can be applied to define the local flow conditions and to indicate the position of the "paleo" source region. However, this technique is quite new in Greece. Some preliminary results from volcanic formations of continental Greece and Southern Aegean are presented (Aegina, Almopia, Elatia, Gavra, Kos, Patmos, Samos, Samothraki and Santorini).

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“…Their preservation would have been made possible by the formation of an E-W crustal sag or topographic depression south of the future Potiguar rift zone. Such a depression might have been linked to the magmatic activity (E-W dyke swarms) and the related crustal deformation that occurred between 145 and 130 Myear (Carneiro et al 1989;Oliveira and Gomes 1996;Archanjo et al 2000).…”

Section: The Araripe Basin a Keystone For Understanding Postcenomanimentioning

confidence: 99%

Stepped Surfaces, Palaeolandforms and Morphostratigraphy: Reconstructing the Long-Term Landscape Evolution Since the Mesozoic

Peulvast

Bétard

2015

Landforms and Landscape Evolution of the Equatorial Margin of Northeast Brazil

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The present relief reflects a juxtaposition of highly contrasting elements of various ages. The landscape formed in the context of a fluctuating but continuously falling base level since the Cenomanian. After formation of the transform passive margin in Aptian times, landscape development was further driven by regional swell-like uplift. The seaward flank of this broad monocline was eroded, whereas the post-Cenomanian uplift caused an inversion of the Cretaceous basins and generated a landscape in which the most elevated landforms correspond either to resistant Mesozoic sedimentary caprock, or to eroded stumps of syn-rift Cretaceous footwall uplands. Some topographic surfaces at low elevations are Mesozoic land surfaces that became re-exposed in Cenozoic times. Denudation in the last 90 Myear never exceeded mean rates of 10 m Myear −1 and exhumed various Cretaceous stratigraphic unconformities. Obtained by morphostratigraphic methods, these results differ significantly from published AFT-derived estimates reported from Palaeozoic and Mesozoic sandstones of the Araripe basin, implying burial by a considerable thickness of younger section and, later, 1.5 km of post-rift denudation, i.e. two to three times as much as our maximum 0.6-0.7 km estimation. The likelihood of such a scenario is discussed, in the light of the exhumation of surrounding basement surfaces, which probably began very early, as shown to the northwest of the Chapada do Araripe by the presence of widespread laterites of probable Paleogene age. The distribution of these paleosoils indicates an early beginning of the basin topographic inversion, which might correspond to the first post-rift denudation episode reported by the AFTA. The second one, in the Oligocene and later, would correspond to the major stage of river incision and basin inversion. The origin of the discrepancy between the two sets of results is discussed, as well as the causes and exact timing of post-Cenomanian crustal upwarping.

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Magnetic fabric of a basaltic dyke swarm associated with Mesozoic rifting in northeastern Brazil

Cited by 40 publications

References 24 publications

Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Anisotropy of Magnetic Susceptibility (Ams) in Volcanic Formations: Theory and Preliminary Results From Recent Volcanics of Broader Aegean.

Stepped Surfaces, Palaeolandforms and Morphostratigraphy: Reconstructing the Long-Term Landscape Evolution Since the Mesozoic

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