Geologica acta

Geologica acta 5 records found  Search took 0.01 seconds. 
1.
32 p, 2.0 MB The Parautochthonous Gondwanan origin of the Cuyania (greater Precordillera) terrane of Argentina : a re-evaluation of evidence used to support an allochthonous Laurentian origin / Finney, S. C. (California State University. Department of Geological Sciences)
A substantial, diverse body of evidence has been interpreted as suggesting that the Cuyania terrane of northwestern Argentina, which includes the Argentine Precordillera, rifted from the Ouachita embayment of Laurentia in the Early Cambrian, drifted across the Iapetus ocean as a microcontinent, and docked with the proto-Andean margin of Gondwana in the Mid to Late Ordovician. [...]
2007 - 10.1344/105.000000300
Geologica acta, Vol. 5, Núm. 2 (2007) , p. 127-158  
2.
8 p, 497.0 KB Paleoethology : fossilized behaviours in amber / Arillo, Antonio (Universidad Complutense de Madrid. Departamento de Zoología y Antropología Física)
When organisms became trapped in sticky resin they usually expired so quickly that they could fossilize in almost lifelike circumstances. Based on frequent description in literature of many examples we propose in this paper a classification of these paleobehaviours.
2007 - 10.1344/105.000000301
Geologica acta, Vol. 5, Núm. 2 (2007) , p. 159-166  
3.
9 p, 388.3 KB Is there a Grenvillian basement in the Guerrero-Morelos Platform of Mexico? / René Levresse, Gilles Pierre (Universidad Nacional Autónoma de México. Programa de Geofluidos, Centro de Geociencias) ; Tritlla i Cambra, Jordi (Universidad Nacional Autónoma de México. Programa de Geofluidos, Centro de Geociencias) ; Deloule, Etienne (Centre de Recherches Pétrographiques et Géochimiques (França)) ; Pinto Linares, Porfirio Julio (Instituto Potosino de Investigación Científica y Tecnológica (Mèxic). Departamento de Geología Económica)
In the Guerrero-Morelos platform (Guerrero State, Mexico) the adakitic rocks of Early Tertiary age contain abundant hornblende-rich tonalite xenoliths. Zircon crystals have been concentrated from both adakites and xenoliths, and dated using in-situ U-Pb ion microprobe analyses. [...]
2007 - 10.1344/105.000000302
Geologica acta, Vol. 5, Núm. 2 (2007) , p. 167-175  
4.
16 p, 1.2 MB Controlling factors on clay mineral assemblages : insights from facies analysis of Pliocene to Pleistocene coastal margin deposits, Western Portugal / University of Coimbra. Department of Earth Sciences, Geosciences Centre
The clay fractions in the Pliocene to Pleistocene coastal margin record are usually dominated by kaolinite and illite, with lesser amounts of vermiculite, 10-14 mixed layer clays and smectite. The high clay mineral crystallinity, the mineralogical relations to facies and depositional setting and some horizontal variations along coeval deposits suggest that clay assemblages are mainly detrital. [...]
2007 - 10.1344/105.000000303
Geologica acta, Vol. 5, Núm. 2 (2007) , p. 177-192  
5.
6 p, 824.4 KB On the Upper Ordovician unconformity in the Pyrenees : new evidence from the La Cerdanya area / Casas Tuset, Josep Maria (Universitat de Barcelona. Departament de Geodinàmica i Geofísica) ; Fernández, Óscar (Midland Valley Exploration)
In recent years, contradictory reports about whether or not an unconformity exists at the base of the Upper Ordovician succession of the Pyrenees have been made. In the Cerdanya area (Central Pyrenees), good outcrop evidence for this unconformity is displayed at the base of the Rabassa conglomerates. [...]
2007 - 10.1344/105.000000304
Geologica acta, Vol. 5, Núm. 2 (2007) , p. 193-198  

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