9 results on '"Postigo-Mijarra, José María"'
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2. Early Miocene fluvial-lacustrine and swamp vegetation of La Rinconada mine (Ribesalbes-Alcora basin, Eastern Spain)
- Author
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Barrón, Eduardo and Postigo-Mijarra, José María
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MIOCENE paleoecology , *SWAMP plants , *GEOLOGICAL basins , *SEDIMENTS , *BOTANY , *PLANT species - Abstract
Abstract: The sediments of La Rinconada mine (Ribesalbes-Alcora basin, Province of Castellón, Eastern Spain) have yielded one of the Early Miocene''s richest megafloral assemblages in the southwestern Mediterranean. At this site, we have found a large amount of leaf compressions and impressions without preserved cuticle. We have identified a total of 31 species of vascular plants: 1 horsetail, 1 fern, 4 conifers, 23 arboreal or bushy dicotyledoneous angiosperms and 2 monocotyledoneous angiosperms. These fossils reveal the presence during the first half of the so-called Miocene Climatic Optimum of a fluvial-lacustrine flora with well diversified mixed broadleaved deciduous and coniferous taxa. Arctotertiary elements dominate the assemblage, whereas Palaeotropical taxa scarcely occur. The occurrence of Trigonobalanopsis exacantha and Trigonobalanopsis rhamnoides is conspicuous as these are common in humid subtropical evergreen vegetation during the climatic optima in the European Oligocene and Miocene. In the La Rinconada outcrop, there is a noteworthy lack of some taxa such as Juglandaceae, Nyssa and Quercus in comparison with other contemporaneous European floras. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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3. Vegetation and environmental conditions in the Doñana Natural Park coastal area (SW Iberia) at the beginning of the last glacial cycle
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Morales-Molino, César, Postigo-Mijarra, José María, García-Antón, Mercedes, and Zazo, Cari
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GEOMORPHOLOGY , *GLACIERS , *PLANTS , *POLLEN , *FOSSIL trees , *PLEISTOCENE palynology , *PLEISTOCENE paleoclimatology , *MYRICA , *BIOGEOGRAPHY - Abstract
Abstract: Detailed reconstructions of the vegetation of Iberia during the last glacial inception are rare due to the limited number of terrestrial sites recording this period. Active retreat of El Asperillo cliff, located on the Atlantic coast of southwestern Iberia, has exposed a fossil organic level dating back to one of the early stades of the last glacial cycle. Pollen and macrofossil analyses from this site show that the Doñana area was covered mainly by steppic vegetation; temperate trees survived the coldest periods, albeit in reduced numbers. Mediterranean taxa are extremely reduced, in contrast with other dry areas of southern Iberia over this time span. This vegetation suggests cold and arid climatic conditions, in accordance with paleoclimatic reconstructions based on several Atlantic marine cores. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
4. Patterns of extinction and persistence of Arctotertiary flora in Iberia during the Quaternary
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Postigo-Mijarra, José María, Morla, Carlos, Barrón, Eduardo, Morales-Molino, César, and García, Salvia
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PALYNOLOGY -- Quaternary , *CLIMATE change , *PLEISTOCENE paleobotany , *HOLOCENE palynology , *FOSSILS - Abstract
Abstract: The native or allochthonous nature of certain extant species of the Iberian Peninsula is a matter of some controversy given our lack of knowledge regarding the survival and extinction processes to which they have been subject. The aim of the present work is to provide a review of the current knowledge regarding these processes during the Quaternary. The Middle Pleistocene Transition was a period of noticeable disappearance of Arctotertiary taxa in the Iberian Peninsula, related to the alteration in glacial cyclicity and climate change, including an increase in the severity of glaciations, a reduction in the length of the interglacial periods, and increased dryness during the coldest times. It is difficult to maintain that human activities played any important part in the complete or near-complete disappearance of some taxa during the Quaternary. In the Late Pleistocene and Holocene, however, the extinction of Cedrus, Picea and Carpinus might be related to climate change, competition with other taxa, and anthropogenic disturbances. In contrast, the extreme reduction or even complete disappearance of Platanus or Syringa seems to be due to natural causes alone. The available geological, molecular and palaeobotanical data suggest that some Arctotertiary taxa persisted over long periods of time during the Quaternary in the Iberian Peninsula. Indeed, the fossil record of one important group of taxa, including Castanea, Ceratonia, Carpinus and Juglans, shows its continued presence throughout the Quaternary. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
5. Palaeoecological significance of Late Pleistocene pine macrofossils in the lower Guadalquivir Basin (Doñana natural park, southwestern Spain)
- Author
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Postigo-Mijarra, José María, Manzaneque, Fernando Gómez, Juaristi, Carlos Morla, and Zazo, Cari
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PALEOECOLOGY , *PLEISTOCENE palynology , *PINE , *FOSSIL plants , *PALEOBOTANY , *FOSSIL trees , *CLIMATE change , *RADIOCARBON dating - Abstract
Abstract: This paper reports on analysis of plant macrofossils in aeolian deposits exposed in El Asperillo cliff in the Province of Huelva. A significant find of a large number of macrofossils of Pinus (Pinus pinaster Ait. and Pinus nigra Arnold) makes a major contribution to our understanding of the role of Pine in the Upper Pleistocene landscapes of Iberia. P. pinaster Ait. and P. nigra Arnold, are meso-microthermic species and inhabited valleys excavated in aeolian sediments mainly deposited during OIS 4 and OIS 3 (based on OSL and radiocarbon ages). Their presence in these valleys during the last part of OIS4 and OIS 3 reflects a significant fall in temperature during certain periods of these isotopic stages and helps us better understand the response of coastal dynamics to climate change. [ABSTRACT FROM AUTHOR]
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- 2010
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6. A palaeoecological interpretation of the lower–middle Pleistocene Cal Guardiola site (Terrassa, Barcelona, NE Spain) from the comparative study of wood and pollen samples
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Postigo Mijarra, José María, Burjachs, Francisco, Gómez Manzaneque, Fernando, and Morla, Carlos
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WOOD , *PALYNOLOGY , *POLLEN - Abstract
Abstract: The Cal Guardiola site, discovered during the construction of an office building in the centre of Terrassa (Province of Barcelona, NE Spain), is home to one of the richest deposits of lower–middle Pleistocene flora in the Iberian Peninsula. The site contains a large quantity of plant macroremains, including non-carbonised wood, in an exceptional state of preservation. In this work, 100 wood fragments were analysed along with 25 pollen samples and 2 coprolites, all from the same horizon. These remains revealed the presence of a mixed deciduous forest with significant numbers of Quercus (Quercetum mixtum). Thermophilous, meso-hygrothermophilous and river forest species were also present, including some taxa rarely recorded for the Pleistocene, e.g., the mesocratic group of species represented by Juglans, Carya and Platanus. Fossil wood of Aesculus was also identified; this is the first Pleistocene reference of this species in Iberia. In this open Mediterranean forest, several remarkable gymnosperms were present. For example, Pinus haploxylon-type pollen was identified, demonstrating the survival of this group of conifers during the lower Pleistocene in the Iberian Peninsula. Pollen of Taxodiaceae was also found — the first reference of this family for the Iberian Pleistocene-showing these taxa survived on the Peninsula until the lower–middle Pleistocene transition. Warm-temperate and humid conditions prevailed during this interval; clear indications of an interstadial episode were observed. [Copyright &y& Elsevier]
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- 2007
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7. Holocene woodland history of the Sierra de Ayllón (central Spain).
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García-Antón, Mercedes, Génova, Mar, Postigo-Mijarra, José María, García-Álvarez, Salvia, Morla, Carlos, and García-Amorena, Ignacio
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HOLOCENE Epoch , *FORESTS & forestry , *SCOTS pine , *BEECH , *PALEOECOLOGY , *PALYNOLOGY , *TREE-rings - Abstract
Integration of a diverse set of data from pollen, wood, macrofossils and dendrochronological studies from the Sierra de Ayllón, a mountainous region in central Spain, enables one of the most complete palaeoecological vegetation reconstructions for almost the whole Holocene on the Iberian Peninsula. Previously, the absence of pollen data for the early Holocene in the eastern part of the Sistema Central mountains had been a gap in the information needed for correctly reconstructing palaeoenvironmental change there. Our pollen study on the Valdojos site finally allows this issue to be resolved. This analysis highlights the crucial role played by pine woodlands throughout the first half of the Holocene in this region. The importance of the pine woods in the region enables us to show the clear difference in vegetation between the western and eastern parts of the Sistema Central mountains for the early to mid Holocene. Moreover, the Fagus pollen found at Valdojos, dating to ca. 7,000–6,600 cal years bp, is the oldest beech record for the central and eastern part of this chain of mountains during the Holocene. This supports the hypothesis of the existence of beech refuges in the Sistema Central for this time span. Furthermore, we used the tree-ring series from the Pinus cf. sylvestris subfossil wood from the Sandria site to extend the previous data from the Sierra de Ayllón to almost the entire Holocene. This tree-ring record is the most complete data set from the Iberian Peninsula and southern Europe and it also provides data on some aspects of the palaeoenvironment. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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8. The Cenozoic vegetation of the Iberian Peninsula: A synthesis
- Author
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Barrón, Eduardo, Rivas-Carballo, Rosario, Postigo-Mijarra, José María, Alcalde-Olivares, Cristina, Vieira, Manuel, Castro, Lígia, Pais, João, and Valle-Hernández, María
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CENOZOIC palynology , *RAIN forests , *PALEOGENE palynology , *MANGROVE swamps , *CLIMATE change , *PALEOCLIMATOLOGY - Abstract
Abstract: The aim of this work is to provide a first approach to the evolution of Iberia''s vegetation during the Cenozoic (with the exclusion of the Quaternary). The Palaeogene was floristically defined by Palaeotropical elements forming tropical/subtropical rainforests, mangrove swamps, edaphically-mediated laurophyllous forests and leguminous-sclerophyllous communities. During the Miocene, Iberian landscapes were drastically modified due to geographic and climatic changes (mainly cooling and aridification) changes. Open, steppe-like environments developed towards the interior of the peninsula and Arctotertiary elements invaded mountainous and riparian ecosystems, coexisting with or becoming part of evergreen, broadleaved forests of Palaeotropical species. From the Late Miocene onwards these forests suffered changes due to the extinction of taxa, the impact of environmental change on the survivors, and the perturbations caused by the arrival of further Arctotertiary elements. However, several Palaeotropical taxa overcame the environmental and climatic changes of the Miocene and Pliocene to form a part of the modern flora of the Iberian Peninsula. [Copyright &y& Elsevier]
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- 2010
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9. Exceptionally well-preserved vegetal remains from the Upper Cretaceous of 'Lo Hueco', Cuenca, Spain.
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Cambra‐Moo, Oscar, Barroso‐Barcenilla, Fernando, Coruña, Francisco, and Postigo‐Mijarra, José María
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PLANT shoots , *ORGANS (Anatomy) , *WOODY plants , *BIOTIC communities , *SULFATE minerals - Abstract
Vegetal remains are considered labile structures that quickly become decayed in ecosystems. However, certain lignified tissues (woody plants) can largely resist decomposition, becoming sometimes exceptionally well preserved. At the Upper Cretaceous site of 'Lo Hueco' (Cuenca, Spain), those woody remains (trunks and branches) with resinous material in the inner tracheids and parenchyma cells that were buried rapidly under anoxic conditions experienced a low degree of maturation, becoming exceptionally well preserved. Those woody remains deposited under oxic conditions (sub-aerial or sub-aquatic exposure) were more intensely biodegraded and subsequently carbonified, partially or completely mineralized in gypsum and covered by a ferruginous crust. These two modes of preservation are scarce, with silicification or carbonification processes much more common, and both can be considered as 'exceptional preservation'. Other vegetal remains, such as carbonified leaves, stems and roots, were collected in the site. The different modes of preservation depend directly on: depositional micro-environment (sandy distributary channel, muddy flood plain); and type (trunk, branch, stem, leave, root) and state (presence or absence of resinous material) of the material. The great abundance and diversity of fossils in 'Lo Hueco' identify it as Konzentrat-Lagerstätten, sequentially formed by alternated events of flooding and drying depositional events, but the exceptional quality and rarity of determinate vegetal macroremains preservation suggest that certain deposits of this site can be considered as conservation deposits. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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