Resumen: A new Isostatic Residual Anomaly Map of the Iberian Peninsula and surrounding marine zones has been made. This map is based on an Airy-Heiskanen isostatic model with local compensation. The key parameters for the model are: depth to the bottom of the Airy-Heiskanen root at sea level, density contrast across the root and topographic density. This map reveal more clearly than the Bouguer Anomaly Map the density distributions
within the crust and shows good correlation with the main geological features of the Iberian Peninsula
Resumen: Se analiza la distribución, habitats y rasgos anatómico-morfológicos presetes en los restos fósiles del género Acrostichum, durante el Terciario en América y Europa, comparándolos con los de A. aureum LINNEO, actual y A. preaureum ARNOLD & DAUGHERTY, fósil.
[ABSTRACT]
Distribution, habitats and morphological-anatomical features of the fossil remains of the genus
Acrostichum during the American and European tertiary are analysed and compared with those of the Acrostichum aureum LINNEO and A. preaurem ARNOLD & DAUGHERTY.
Resumen: Entre los principales rasgos que caracterizan la obra del arquitecto gallego Antonio Palacios, cuyo interés geológico resulta excepcional, cabe destacar la materialidad pétrea de sus construcciones así como su apuesta por la conservación y difusión del patrimonio cultural. El estudio de la piedra natural que configura el legado
de Antonio Palacios permite entender mejor su pensamiento, atender al sustrato geológico próximo a los lugares donde construía o conocer los caracteres petrológicos de los materiales, que tan directamente participan en la textura que Palacios quiso otorgar a sus construcciones y que condicionan su estado de conservación. Además, posibilita conocer los motivos que favorecieron su selección, donde la situación por entonces de las canteras y de los medios de comunicación juegan un papel fundamental.
[ABSTRACT]
Among the main features that characterize the artwork of the architect Antonio Palacios, which geological interest is exceptional, the stonework of its constructions and its commitment with heritage conservation and dissemination should be mentioned. The study of natural stone which shapes Palacios´ legacy let its better understanding, to pay attention to the geological settings or to know the petrological characters of the buildings materials, so directly involved in the texture Palacios wanted to provide to its façades and with the materials decay. Besides, it enables to know the reasons that favored its selection, where the formerly quarries state and transport development play a fundamental role.
Palabras clave: Geología, Materiales pétreos, Conservación, Patrimonio construido, Canteras, Divulgación, Geology, Building materials, Conservation, Built heritage, Quarries, Dissemination
Resumen: En el norte de la Provincia de Granada los materiales eocénicos afloran bajo dos facies diferentes que se denominan
como dos Formaciones: facies de calizas (Formación de Cañada Hermosa) Y. hacia el Sur, facies margosas y
lutíticas con algunas calizas detríticas intercaladas (Formación de N ahlanca), Existe un cambio de litofacies desde el
Norte (facies calizas) hacia el Sur (facies margosas)
y, al mismo tiempo, la potencia se incrementa nota:b!emente.
En este trabajo se estudiarán la composición, textura, fósiles y estructuras sedimentarias primarias, a fin de obtener
la interpretación sedimentaria de la Formación de Nab1anca.
Se considera que la más adecuada sería un medio marino de plataforma abierta, con una marcada influencia continental
debida a un ambiente deltaico fluviomarino (prodelta).
Finalmente, se proponen varias hipótesis para explicar la distribución palaeogeográfica de la región.
[ABSTRACT]
In the North of the Province of Granada, eocenie materials outcrop under two different facies, vhich are named
as two Formations: -limestone facies (Cañada Hermosa Formation) and, southwards, marly and lutitic facies with some
detritic limestone interbedded (Nablanca Formation). There exists a lithofacies change from North (1imestone facies)
towarss South (marly facies) and, at the same time, the thickness notably increases.
In this paper, we shall study composition, texture, fossi1s and primary sedimentary interpretation of Nablanca
Formation.
We consider that the most suirtab1e would be a marine open shelf environment with a marked continental influence,
due to a fluviomarine deltaic environment (prodelta).
To conclude, we propose several hypothesis to explain the palaeogeographic distribution of the area.
Palabras clave: Eoceno; Nablanca; Cañada Hermosa; Pontones; Puebla de Don Fabrique
Resumen: The Allou Kagne (Senegal) deposit consists of different proportions of palygorskite and
sepiolite, and these are associated with small quantities of quartz and X-ray amorphous silica as impurities.
No pure palygorskite or sepiolite has been recognized by X-ray diffraction. Textural and microtextural
features indicate that fibrous
clay minerals of the Allou Kagne deposit were formed by direct precipitation
from solution. Crystal-chemistry data obtained by analytical/transmission electron microscopy (AEM/
TEM) analyses of isolated fibers show that the chemical composition of the particles varies over a wide
range, from a composition corresponding to palygorskite to a composition intermediate between that of
sepiolite and palygorskite, but particles with a composition corresponding to sepiolite have not been found.
Taking into account the results from selected area electron diffraction and AEM-TEM, fibers of pure
palygorskite and sepiolite have been found but it cannot be confirmed that all of the particles analyzed
correspond to pure palygorskite or pure sepiolite because both minerals can occur together at the crystallite
scale. In addition, the presence of Mg-rich palygorskite and very Al-rich sepiolite can be deduced.
It is infrequent in nature that palygorskite and sepiolite appear together because the conditions for
simultaneous formation of the two minerals are very restricted. The chemical composition of the solution
controls the formation of the Allou Kagne sepiolite and palygorskite. The wide compositional variation
appears as a consequence of temporary variations of the chemical composition of the solution.
Resumen: A pesar del extenso registro fósil del Mioceno español, es escaso el conocimiento de yacimientos provenientes de depósitos que cubran
el tránsito Aragoniense-Vallesiense. Durante los últimos años, nuevos muestreos paleontológicos se han llevado a cabo en el área de Daroca (Zaragoza, España) para completar la información sobre este intérvalo. Además se han realizado estudios litoestratigráficos
y muestreos magnetoestratigráficos. El resultado de dichos estudios pone de manifiesto la existencia, en el área de Daroca-Nombrevilla, de una sección estratigráfica que incluye quince yacimientos fosilíferos (de los cuales nueve son de reciente hallazgo) y que viene a completar el conocimiento del registro fósil del Aragoniense superior-Vallesiense inferior.
[ABSTRACT]
Despite the extensive continental fossil record from the Spanish Miocene, few localities from deposits covering the Aragonian-Vallesian boundary are known. During the last few years new sampling has been carried out around Daroca (Zaragoza, Spain) in order to complete the information of that interval. In addition, lithostratigraphic and sedimentological studies as well as magnetostratigraphic
sampling have been done. The results of all these studies allow to recognise a stratigrafic section that includes fifteen mammal fossil localities (of which nine are new) completing our knowledge of the fossil record of the upper Aragonian-lower Vallesian.