0000000000266444
AUTHOR
María Eugenia Dies ÁLvarez
Proposal of a reference section and point for the Cambrian Series 2-3 boundary in the Mediterranean subprovince in Murero (NE Spain) and its intercontinental correlation
The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the Cambrian Series 2 and 3, which is now in the process of definition by the International Subcommission on Cambrian Stratigraphy. Currently, there are two oryctocephalid trilobite species first appearance data (FAD) that are suggested as possible markers of this level: Ovatoryctocara granulata Tchernysheva, 1962 and Oryctocephalus indicus (Reed, 1910), respectively. Until now neither of these two species has been recorded in the Mediterranean subprovince or Baltica. As a result, in these regions a level potentially correlating with either the FAD of Ovatoryctocara granulata or Oryctocephalus indi…
ParadoxidesbrachyrhachisLinnarsson, 1883 versusParadoxidesmediterraneusPompeckj, 1901: a problematic determination
A revision of paradoxidid trilobites reveals that previous identifications of specimens from Sardinia and Spain as the Nordic trilobite species Paradoxides brachyrhachis Linnarsson, 1883, are mistaken. The southern species, occurring also in France, is here referred to Eccaparadoxides mediterraneus (Pompeckj, 1901). Main differences are seen in the preocular field, pleural furrow and pygidium. The species P. brachyrhachis is referred with question to the genus Mawddachites Fletcher 2007.
Bradoriid Arthropods from the Lower-Middle Cambrian of Scania, Sweden
Three species of bradoriid arthropods from the lower to middle Cambrian transitional interval of Scania, southern Sweden, are described and illustrated: Beyrichona tinea from the top of the traditional lower Cambrian (Gislov Formation; Ornamentaspis? linnarssoni Zone), and Hipponicharion eos and Alutella sp. from the basal portion of the traditional middle Cambrian (lowermost part of the Alum Shale Formation). The bradoriid fauna compares most closely with others previously described from western and eastern Avalonia (New Brunswick and England). The record of B. tinea suggests a correlation between the “Protolenus Zone” (Hupeolenus Zone) of western Avalonia and the O.? linnarssoni Zone of S…
Cerro del Hierro, Spain: the largest exposed early Cambrian palaeokarst
AbstractWe study the largest exposed example of an early Cambrian palaeokarst, associated with laterites and developed during rifting of the Ossa–Morena Zone. The lithostratigraphy, biostratigraphy, facies and the genesis reflect episodes of sea-level fall (Cerro del Hierro Regression) related to tectonic events and palaeoclimate. This palaeokarst can be primarily considered as the result of early Cambrian polyphase karstification in an extensional tectonic regime, later modified by Neogene–Quaternary geomorphological processes. The event may correlate with other regressive events of a similar age in Spain, Italy, United Kingdom, South America and Australia. This episode also has local name…
El género Hamatolenus Hupé, 1953 (Cámbrico Inferior-Medio) en Murero y áreas adyacentes de las CadenaS Ibéricas (NE de España)
Hasta la fecha, se han definido tres subgeneros de Hamatolenus Hupe, 1953: H . ( Hamatolenus ) Hupe, 1953, H . ( Myopsolenus ) Hupe, 1953 y H . ( Lotzeia ) Sdzuy, 1958. En Espana se conocian solo representantes de los dos primeros con las especies H . ( Hamatolenus ) ibericus Sdzuy, 1958 y H . ( L .) lotzei Sdzuy, 1958. Se presenta aqui el primer ejemplar de Hamatolenus ( Myopsolenus ) encontrado en la Peninsula Iberica. El analisis de la distribucion estratigrafica del genero Hamatolenus muestra su potencial para la correlacion de las materiales situados entorno al limite Cambrico Inferior y Medio, para las facies siliciclasticas en el ambito perigondwanico. Ademas, desde un punto de vista…