Wolfgang Volkheimer

Palynology and paleoenvironment of the "Faja Gris" Mealla Formation (Salta Group) at Garabatal Creek (NW Argentina)

Abstract An integrated biochronological and physical stratigraphie approach was used as the basis to determine the stratigraphic position of the “Faja Gris”; of the Mealla Formation at Garabatal Creek, NW Argentina. The relative dryness that influenced the sediments and the palynological assemblage of the “Faja Gris”; can be correlated with an episode of relative low sea level in the marine Atlantic basins during the Riochican Land Mammal Age (Middle to Late Paleocene). The comparison of fossil genera with extant taxa permits recognition of several paleocommunities, namely marsh, lacustrine, fluvial, montane forest, cloudy forest, transitional forest and steppe. The megaspore species Grapnelispora evansii has its youngest and northernmost occurrence in the Mealla Formation. Based on the palynological and sedimentological results, the analyzed profile would be located on the calcareous pelite plain environment defined by Gomez Omil et al. (1989) for the “Faja Gris.”;

A Danian subtropical lacustrine palynobiota from South America (Bororó Formation, San Jorge Basin, Patagonia - Argentina)

New results on a lacustrine Danian palynological association in extra-andean northern Patagonia (lower member of the Cerro Bororo Formation, San Jorge Basin, Chubut province, Argentina) are presented. This is a contribution to the largely unexplored field of Paleogene freshwater environments. The palynobiota includes representatives of the kingdoms Protoctista and Plantae. Twelve of the aquatic species are Protoctista. From the nine Chlorophyta form-species, four correspond to Botryococcaceae, one to Coelastraceae and four to Zygnemataceae (Gelasinicysta, Schizosporis, Ovoidites, and Pseudoschizaea). The remaining forms are dinoflagellate cysts (Peridinium and dinocyst indet.) and prasinophyceans (Leiosphaeridia). Plants are represented by spores and pollen of Bryophytes (Sphagnaceae and Ricciaceae), Pteridophytes (Salviniaceae), and Angiosperms (Arecaceae, Araceae and Sparganiaceae/Typhaceae, the latter representing macrophytes living in or near the swampy areas). Other palynomorph groups closely related with biotopes of permanent moisture are dominated by spores of the families Selaginellaceae, Lycopodiaceae, Cyatheaceae, Schizaeaceae, Polypodiaceae and Psilotaceae. The palynological assemblage reflects a freshwater lacustrine environment that developed in a marine coastal zone nearby brackish coastal swamps. Based on the composition of the palynoflora including palm pollen and other thermophilous taxa, humid, warm climatic conditions are inferred for the area of deposition.

Jurassic and Lower Cretaceous dinocysts from Argentina : their biostratigraphic significance

Abstract Dinocyst assemblages from the Cura Niyeu Formation (Bajocian), the Lotena Formation (middle to late Callovian), the lower Vaca Muerta Formation (early to middle Tithonian), the Picun Leufu Formation (late middle to late Tithonian), the upper Vaca Muerta Formation (Berriasian) and the Agrio Formation (Hauterivian to Barremian) of the Neuqeun Basin, central western Argentina, are recorded. The Bajocian assemblage is characterized by an improvished flora including Batiacasphaera sp., Nannoceratopsis sp. and Rhaetogonyaulax sp.; the Callovian assemblages by Lithodinia jurassica, Nannoceratopsis pellucida and Scriniodinium galleritum subsp. reticulatum ; the lower and middle Tithonian by the endemic Hystrichospherina neuquina ; the Picun Leufu Formation marked by the first appearance of Dichadogonyaulax culmula ; the Berriasian by Cribroperidinium reticulatum and Millioudodinium ambiguum and the first appearance of Pseudoceratium cf. gochtii and Cribroperidinium orthoceras are noted in the Hauterivian. All suites show restrcted diversity and are dominated by acavate, proximate species. Higher dinocyst diversity in the Late Jurassic and Early Cretaceous may reflect a warming trend.

Early Cretaceous dinoflagellate cysts from the southern border of the Neuquén Basin, Estancia Santa Elena locality, Argentina *

An assemblage of dinoflagellate cysts is reported from the Lower Member (Pilmatue Member) of the An assemblage of dinoflagellate cysts is reported from the Lower Member (Pilmatue Member) of the Agrio Formation (late Valanginian-Hauterivian) of the southern Neuquen Basin, Argentina. Thirty species are recognized and the new species Oligosphaeridium quattrocchioae and Muderongia sarjeantii described. The studied assemblage is compared with other Early Cretaceous assemblages from central western Argentina, Patagonia, the South Atlantic Malvinas Plateau, the Antarctic Peninsula and Australia. The marine dinoflagellate cyst assemblage of the Agrio Formation at the Estancia Santa Elena locality has cosmopolitan character, with a predominance of European and Tethyan species.

Técnicas extractivas y preparativas en Paleontología: Aspectos ambientales y de seguridad laboral

Extractive and preparation techniques in Paleontology. Environmental aspects and labor safety. The objective of this paper is to analyze the working conditions in which the paleontologic work is developed, especially in Paleopalynology and Paleovertebratology. This analysis is also valid for other academic and scientific activities. During fieldwork and in the paleontologic research a wide range of processes are applied, which proceed from the fields of physics and chemistry. They are characterized by different degrees of complexity and present different types of risks for the people who apply them, for other people, for physical objects and for the environment. For the applications of all these technical activities, some aspects must be taken into account that are not perceived as scientific matter and consequently do not receive attention: the safety of working conditions. This situation determines a state of precarious conditions of the labor environment and certain degree of stress, which potentiates the generation of accidents and damages and is hurting the legislation and the codes of professional ethics. The violation and absence of application of these rules are occurring frequently. The origin of this behavior may be due to the lack of knowledge and interest, and a certain degree of collective anomie that characterizes our society. In our labor environment –even without existing statisticsthe cases of accidents and damage affecting health, as well as factors of risk and probable dysfunctional behaviors which are producing them, are frequent. This paper introduces in the problematic of the risks, exposes the normative marks and develops an interpretation of the possible causes that would explain the breach of the established thing in the matter of labor safety. It also proposes possible strategies destined to mitigate, to correct and to revert this problem.