RT Dissertation/Thesis
T1 Nuevas aportaciones a la palinoestratigrafía pérmica del dominio peritético occidental
T2 New contributions to the permian palynostratigraphy of the occidental PeriTethyan domain
A1 Juncal Rosales, Manuel Antonio
K1 2416.03 Palinología
K1 2416.04 Paleontología de las Plantas
K1 5505.12 Estratigrafía
AB The definition of a palynostratigraphic framework for the late Carboniferous-Permian interval is conditioned by the intense environmental changes resulting from the last phases of the assemblage of Pangea and the formation of the Variscan Belt.During Upper Pennsylvanian – early Permian interval, a geological and climatic transition is observed due to the global warming produced by the glacial retreat. In Western Europe (which during this period was located in low latitudes of the Euramerica Province), this climatic development is shown as a transition from a tropical climate, to sub-humid during most of the Cisuralian (lower Permian) becoming semi-arid at the end of this period. This progressive aridification reaches its peak around the Kungurian-Roadian transit (lower-upper Permian transit) and remains until the Permian-Triassic Boundary.This climatic change produced an increase of the extinction rates on land plants. There was a replacement of hydrophilic floras (“Stephanian floras”) to mesophytic-xerophytic floras (“Autunian floras”) that tolerated dry or seasonally dry environments. This replacement was not isochronous, and autunian floras have been recorded in upper Carboniferous sediments, Stephanian floras in Permian sediments and even mixtures of these floras with other elements of more than one phytogeographical provinces. This “chaotic scene” affects the palynostratigraphy, making the different biostratigraphical schemes differ across Pangea. To date, the correlation between flora assemblages and palynostratigraphic schemes are even now tentative or incomplete.In this context, the results presented in this dissertation provide new information for the resolution of this problem. Materials from upper Carboniferous-upper Permian interval from different points of the Iberian Peninsula, Balearic Islands and France have been studied. The main purpose of these works is to observe the relationship between palynological assemblages and isotopic dating, which allows us to verify the validity of the classical Palynological Zonations of Western Europe (Clayton et al., 1977) and the studies of the Autunian Floras of the French basins: Autun, Blanzy, l’Aumance, Brive and Lodève shown in Doubinger (1974).The works carried out are the following:-	Study and palynological characterisation of Grey Unit (Gisbert, 1981) of the Catalan Pyrenees. Kasimovian – Gzelian age (307.4 ± 1.4 Ma – 302.6 ± 2.6 Ma, Pereira et al., 2014).-	Palynological study of Autunian stratotype, Autun, France. Asselian age (298.57±0.38 – 298.05±0.39 Ma, Pellenard et al., 2017)-	Palynological study of Usclas and Tuilièries-Loiras formations, Lodève. Tuilièries-Loiras Formation is dated as Sakmarian (293.94 ± 0.08 – 293.85   ± 0.10 Ma, Michel et al., 2015).-	Palynology of Sotres Formation, Asturias, Spain. Kungurian age. Comparison with the flora shown in Tregiovo Basin, Italy (276.5±1.1 – 274.1 ± 1.6 Ma; Marocchi et al., 2008).-	Review of the late Permian microflora from the Iberian Peninsula and the Balearic Islands. Joint study and new data.At the same time, a re-study of the classical chemical analysis for palynological samples was necessary, due to the complexity of the French materials, achieving significant advances. These samples are characterised by a large amount of organic matter and variable maturation, causing the classical treatment of HCl-HF-HCl was ineffective. Therefore, the viability of the use of different chemical substances, for the palynomorphs separation, was studied and an action protocol was proposed. Finally, to improve the efficiency of this process (saving time and costs) a rotor was designed that allows that the samples be in continuous movement and the chemical attack be homogeneous at any time.
YR 2019
FD 2019-06-21
LK http://hdl.handle.net/11093/1286
UL http://hdl.handle.net/11093/1286
LA spa
NO Ministerio de España | Ref. CGL2014-52699P
DS Investigo
RD 15-sep-2024