Shallowing-upward cycles in pelagic troughs (Upper Jurassic, Subbetic, Southern Spain)
Abstract Abundant calcareous tempestites with chert and hummocky cross-stratification (HCS) occur in Upper Jurassic successions (Milanos Formation) of the Subbetic (Betic Cordillera, Southern Spain). These calcareous tempestite beds are calcisiltites and very fine calcarenites with peloids and bioclasts, and have thicknesses between 25 and 75 cm. Beds show symmetrical wave ripple lamination near the top, and are usually capped with wave ripples. According to palaeogeographic reconstructions, these strata were deposited in a subsiding trough in the pelagic domain of the Southern Iberian Continental Margin, which was the northwestern-most border of the Tethys. Calcisiltite and calcarenite beds deposited in this pelagic trough form small-scale to large-scale shallowing-upward cycles. Shallowing-upward cycles with calcareous tempestites in the lower part and oolitic limestone beds in the upper part, have also been recognized in some sectors of the Subbetic pelagic basin. The large-scale cycle occurs in the upper part of the Jarropa Radiolarite Formation, which directly underlies upper Oxfordian, Kimmeridgian and Tithonian strata of the Milanos Formation. Two types of large-scale shallowing-upward cycles have been recognized, according to the presence or absence of thick units of oolitic limestone with large-scale cross-stratification. The water depth during deposition ranged from below, but near, storm wave base at the base of the large-scale cycles to very shallow carbonate platform at the top.
Siliceous raw material consumption during the late Upper Palaeolithic in “El Pirulejo”, South of Iberia (Priego, Córdoba)
This work presents the first results about the use of siliceous raw materials by the hunter-gatherer societies during the Late Glacial in the level 5 of El Pirulejo. El Pirulejo is located within the municipality of Priego de Cordoba (Cordoba, Spain).The archaeological level P/5 is classified as a Solutrean, according to the technological analysis of the lithic assemblage. The methodology used about the raw material is divided into four phases. During this first phase, we carried out a sampling analysis of local primary and secondary outcrops in the proximity of the site, over an area of 20 km from the site. We also performed a macroscopic and petrographic analysis of selected samples. In these phase, we describe the Veleta Formation, wich represents the main siliceous outcrop closest to the site. Once the local flint was characterized, it was compared to the lithic industry assemblage of level P/5, with the intention of observing the management and exploitation of local flint associated to knapping activities. As a result of the assemblage analysed so far, we have ruled out local operations on these chert samples and propose an area of exploitation of lithic resources that will exceed 20 kilometres around the site. We ruled out that the Veleta Formation provided a source of lithic supply for the hunter-gatherer societies.
Reid on Hypotheses and the Ether; A Reassessment
In recent years historians of science have come to see that Thomas Reid’s Essays on the Intellectual Powers of Man had a profound impact on the development of British methodological thought in the late-eighteenth and early-nineteenth centuries. Larry Laudan has argued that Reid was “the first major British philosopher to take Newton’s opinions on induction, causality, and hypotheses seriously”; and that Reid was thereby instrumental in changing the character of British methodological discourse in the Enlightenment.(1) Geoffrey Cantor has examined in detail the influence of Reid’s critique of ether theories and hypotheses in the Essays on leading protagonists in the nineteenth-century debates surrounding the wave theory of light,(2) and Richard Olson has traced the origins of the scientific style of British physics in the Victorian period to the writings of Reid and other Common Sense philosophers. (3) As well as delineating Reid’s influence, Laudan, Cantor, and Olson have attempted to identify the problems to which he addressed himself in articulating his methodology, and they have analysed with some care the internal structure of his methodological views. Thanks to the work of these historians, therefore, we have a fairly comprehensive picture of Reid’s methodology and its fortunes in the nineteenth century.