José Carlos Kullberg

A review of Alpine tectonics in Portugal: Foreland detachment in basement and cover rocks

Abstract The Alpine foreland in Portugal was deformed by compressional tectonism during the Miocene. In the NNE-SSW oriented Lusitanian Basin, most folds and thrusts in the Meso-Cenozoic cover are oriented ENE-WSW, parallel to the Alpine front in the Betic Cordillera, and verge towards the north-northwest and south-southeast. The thrusts are connected by lateral ramps: most of these are oriented NNE-SSW to N-S and show sinistral movement, and some are transpressional. The lateral ramps result from reactivation of older extensional faults related to crustal thinning of the continental margin. In the E-W oriented Algarve Basin a simpler basin inversion occurred, with older E-W normal faults reactivated as essentially pure thrusts. In both basins Alpine structures formed above decollements in the Hettangian evaporite-clastic complex. Variscan basement was also deformed by ENE-WSW reverse faults during Miocene time. The similarity in orientation and style of the basement structures to those in the cover suggests that they also occurred by detachment, but their larger scale indicates that the detachment is deep and involves much of the crust. Thus, we interpret the Central Cordillera, in which basement rocks are thrust over Miocene sediments on both sides, as a “pop-up” of crustal scale, elevated above downward-flattening faults that dip towards each other and merge into a single deep detachment. Alpine structures in the Iberian foreland are therefore similar in structural style to those of the Appalachian and Laramide forelands of North America and the Alpine foreland of northwest Europe.

Compressive Episodes and Faunal Isolation during Rifting, Southwest Iberia

Evidence for three short‐lived compressive episodes of late Carixian, late Callovian–early Oxfordian, and Tithonian‐Berriasian ages that lasted <5 m.yr. and occurred during the process of rifting of the Algarve Basin is presented. These tectonic‐inversion episodes are described at outcrop and cartographic scales and have been dated with the accuracy provided by the ammonoid scale. An uplift event of late Toarcian–Aalenian age of undetermined tectonic origin is also described. We show that these four tectonic episodes coincide in time with important ecological events, such as the onset of migration and/or the segregation of Boreal and Tethyan ammonite species and the confinement of the Algarve Basin. Stratigraphic and paleoecological data from the Algarve and Lusitanian Basins are compared and discussed together with eustatic and tectonic information. We propose that the tectonic‐inversion episodes that caused uplift are the origin of the Mesozoic sedimentary gaps and the intermittent opening and closure of the seaway located offshore the SW corner of Iberia between the Algarve and Lusitanian Basins (i.e., a seaway between the Boreal and Tethyan realms). Three tectonic mechanisms for the origin of these short‐lived compressive episodes are presented after comparing the tectonic setting of the Algarve Basin with other geological provinces of the world where similar phenomena also occurred.

New evidence of shared dinosaur across upper jurassic proto-North Atlantic: stegosaurus from Portugal

More than one century after its original description by Marsh in 1877, we report in this paper the first uncontroversial evidence of a member of the genus Stegosaurus out of North America. The specimen consists of a partial skeleton from the Upper Jurassic of Portugal, herein considered as Stegosaurus cf. ungulatus. The presence of this plated dinosaur in the upper Kimmeridgian–lower Tithonian Portuguese record and synchronic levels of the Morrison Formation of North America reinforces previous hypothesis of a close relationship between these two areas during the Late Jurassic. This relationship is also supported by geotectonic evidences indicating high probability of an episodic corridor between the Newfoundland and Iberian landmasses. Together, Portuguese Stegosaurus discovery and geotectonic inferences could provide a scenario with episodical faunal contact among North Atlantic landmasses during the uppermost Kimmeridgian–lowermost Tithonian (ca. 148–153xa0Ma ago).

Flat-pebble conglomerates: a local marker for Early Jurassic seismicity related to syn-rift tectonics in the Sesimbra area (Lusitanian Basin, Portugal)

Flat-pebble conglomerates have been identified in the Lower Toarcian (Levisoni Zone) carbonates of the Sesimbra region (30 km south of Lisboa, Portugal) and related to submarine mass movements. Their origin is explained through a three-stage model based on the comparative analysis of potential generating mechanisms taking into account timing and type of geodynamic evolution in the Lusitanian Basin: (a) differential lithification of thin carbonate and non-bioturbated horizons embedded within a more argillaceous matrix; (b) disruption by seismic shocks related to active extensional faulting and block tilting; and (c) gravity sliding mixing material resulting from broken lithified horizons. This sequential process originated flat-pebble conglomerates during early Jurassic phases of syn-rift evolution in the southern Lusitanian Basin. q 2001 Elsevier Science B.V. All rights reserved.

The Paleogene and Neogene of Western Iberia (Portugal): A Cenozoic Record in the European Atlantic Domain

The Portuguese mainland, located in western Iberia, represents a key area for understanding the evolution of the European Atlantic margin during the Cenozoic and the establishment of relations with the Mediterranean, in particular through the transition area between those two oceans which is well documented in the Algarve region.

Palaeogeographical Evolution of the Lusitanian Basin (Portugal) During the Jurassic. Part I: The Tectonic Constraints and Sedimentary Response

In this paper, we present the general tectonic framework that conditioned the evolution of the Lusitanian Basin during the Jurassic, when most of the filling of the basin was accumulated. The rifting episodes and the evolution of the basin’s geometry are presented and their close relationship with the main basin-wide unconformities is discussed. The unconformity-bounded sequences are briefly presented as a basis for understanding the evolution of the sedimentary environments. This constitutes the basic geological information to construct the palaeogeographical maps presented in Part II of this paper (this volume).

Gravimetric and magnetic fabric study of the Sintra Igneous complex: laccolith-plug emplacement in the Western Iberian passive margin

The geometry and emplacement of the ~u200996xa0km2, Late Cretaceous Sintra Igneous complex (SIC, ca. 80xa0Ma) into the West Iberian passive margin is presented, based on structural data, gravimetric modeling, and magnetic fabrics. A granite laccolith (~u200976xa0km2, <u20091xa0km thick, according to gravimetric modeling) surrounds a suite of gabbro–diorite–syenite plugs (~u200920xa0km2, ~u20094xa0km deep) and is encircled by cone sheets and radial dykes. Anisotropy of Magnetic Susceptibility was interpreted from 54 sites showing fabrics of para- and ferro-magnetic origin. Most fabrics can be interpreted to have a magmatic origin, according to the scarcity of solid-state deformation in most part of the massif. Magnetic foliations are shallowly dipping in the granite laccolith and contain a sub-horizontal ENE–WSW lineation. The gabbro–syenite body displays concentric magnetic foliations having variable dips and steeply-plunging lineations. The SIC can be interpreted to be intruded along an NNW–SSE, 200xa0km-long fault, perpendicular to the magnetic lineation within the laccolith, and was preceded by the intrusion of basic sills and plugs. The SIC intruded the Mesozoic series of the Lusitanian Basin during the post-rift, passive margin stage, and its geometry was only slightly modified during the Paleogene inversion that resulted in thrusting of the northern border of the intrusion over the country rocks.

Soft skills for science and technology students: A pedagogical experience

In the academic year 2012-2013, the Faculty of Science and Technology of the New University of Lisbon (FCT/UNL) conducted a complete revision of its curriculum, with the goal of enhancing the training of its students and increasing the employability of its graduates. In its new profile, the FCT/UNL now includes three distinct teaching periods in an academic year, with the introduction of a five-week period between the two traditional semesters. During this period, several transferrable skills courses are taught in an intensive regimen. In this article, we present the motivations that led to the creation of the course entitled “CTCT - Transferable Skills for Science and Technology”, its incorporation into the new curricular profile of the FCT/UNL, its main objectives, and its syllabus. We also present the methods used in the allocation of students to classes and groups and the feedback from teachers and students participating in the course.

Palaeogeographical Evolution of the Lusitanian Basin (Portugal) During the Jurassic. Part II: The Slow-to-Fast Transformations of Sedimentary Infilling

In this paper we present the first palaeogeographical maps of the Lusitanian Basin during the Jurassic. We also present the methodology used to produce these maps and discuss the close relationship of the temporal and spatial distributions of facies with the sequence of tectonic events in the basin (already discussed in Part I of this study, this volume). One of the main conclusions is that the main bordering N–S-trending faults were the main tectonic structures that conditioned the facies geometry but only during paroxysmal events; during those short intervals, “instant” modifications of the facies geometry occurred. The other main conclusion is that in the time intervals between the paroxysmal events, the structures that conditioned the facies distribution were the main transfer faults, oriented ENE–WSW, and the sedimentary environments gradually rotated from N–S to ENE–WSW.

Prospecção interactiva de endocarso através duma aplicação SIG

GIS APPLICATION FOR INTERACTIVE PROSPECTION OF ENDOKARST. The parameters that affect the development of karst erosion at depth – endokarst - are complex and difficult to understand, due to both their diversity and the difficulty of quantifying the actual contribution of each of them. This work presents a methodology developed in a GIS environment with the aim of identifying the areas in which endokarst is most likely to occur. This case study was conducted within a sample area located to the west of Sesimbra where several of these structures have been identified, with a special emphasis on the caves of Zambujal and Frade. The suggested model is based on the interactive combinatory analysis of the dependent variables according to skillful criteria, taking into account their relative contributions to the development of endokarst. One of the main goals of this study is the development of an interactive software application enabling to test and evaluate the relative importance of the selected parameters. A decision was made to use a simple classification of the supervised or skillful type, in which the variables, their inter-relations and their relations with the surrounding areas are conveyed under the summarised form of a ranking of their relative relevance, as measured by their expected contribution to karstification. The output of the model consists of a set of maps that indicate the likelihood of the occurrence of endokarst at any given point. The hierarchical relevance of each variable, the selection of larger or smaller buffer areas for fractures and fracture intersections, the choice of appropriate variables and their subdivision into a number of categories allow for scrutiny to be applied at a series of different levels, rendering possible the skillful calibration of the results to all the places where the predominant geology is of the carbonate type. At the same time, the comparative analysis of these results provides an excellent opportunity for us to understand the parameters that most contribute to the formation of endokarst. The suggested model was tested interactively and the latter analysis and validation of the results allowed for the positive identification of the appropriate sequence of those variables that most affect the formation of endokarst