Paola Pittau

The Jurassic plant fossils of the Lovisato Collection: preliminary notes

A preliminary account is presented herein of the revision of 473 slabs containing macrofossil plant remains from the Domenico Lovisato plant Collection. The latter is housed in the Museo Sardo di Geologia e Paleontologia “D. Lovisato” of the Università di Cagliari. The material examined encompasses palaeobotanical remains collected from the Genna Selole Formation and from the basal part of the Dorgali Formation, both of Jurassic age at a variety of localities in Barbagia and Sarcidano, eastern Sardinia. A reconstruction is given of the history of the collection, initiated in 1888, and the scientific studies of the flora by a variety of palaeobotanists. Based on a preliminary revision of the specimens the following genera are recognized: Phlebopteris Brongniart, 1836, Hausmannia Dunker, 1846, Coniopteris Brongniart, 1849, Cladophlebis Brongniart, 1849, Sagenopteris Presl in Sternberg, 1838, Cycadeospermum Saporta, 1875, Ptilophyllum Morris in Grant, 1840, Williamsonia Carruthers, 1870 emend. Harris, 1969, Weltrichia Braun, 1847 emend. Harris, 1969, Taeniopteris Brongniart, 1828, Czekanowskia Heer, 1876 emend. Harris et al., 1974, Brachyphyllum Brongniart, 1828, Elatocladus Halle, 1913 emend. Harris, 1979 and Carpolithes Brongniart, 1822. Some plant remains have been putatively assigned to the following genera: Ptilozamites Nathorst, 1878 emend. Antevs, 1914, Nilssonia Brongniart, 1825, Pterophyllum Brongniart, 1828 and Geinitzia Endlicher, 1847. Several of these genera are known also from the Jurassic flora of Yorkshire and from other Jurassic floras of Italy. RIASSUNTO [La flora giurassica della Collezione Lovisato: nota preliminare] In questo lavoro vengono presentati i dati preliminari della revisione sistematica di 473 reperti contenenti resti macroscopici di piante fossili della Collezione Lovisato, conservata presso il Museo di Geologia e Paleontologia Domenico Lovisato, dell’Università degli Studi di Cagliari. La collezione comprende resti fossili raccolti in diverse località del Sarcidano e della Barbagia, nella Sardegna orientale, e provenienti dalla Formazione di Genna Selole e dalla porzione basale della Formazione di Dorgali, entrambe di età medio giurassica. Viene ricostruita la storia della collezione e degli studi effettuati su di essa dai vari studiosi che si sono succeduti nel tempo, a partire dal 1888, anno di inizio delle raccolte e dei campionamenti da parte del Prof. Domenico Lovisato. La revisione tassonomica preliminare consente di fornire una lista aggiornata a livello generico delle forme riconosciute nella collezione, che sono: Phlebopteris Brongniart, 1836, Hausmannia Dunker, 1846, Coniopteris Brongniart, 1849, Cladophlebis Brongniart, 1849, Sagenopteris Presl in Sternberg, 1838, Cycadeospermum Saporta, 1875, Ptilophyllum Morris in Grant, 1840, Williamsonia Carruthers, 1870 emend. Harris, 1969, Weltrichia Braun, 1847 emend. Harris, 1969, Taeniopteris Brongniart, 1828, Czekanowskia Heer, 1876 emend. Harris et al., 1974, Brachyphyllum Brongniart, 1828, Elatocladus Halle, 1913 emend. Harris, 1979 e Carpolithes Brongniart, 1822. Anche i generi Ptilozamites Nathorst, 1878 emend. Antevs, 1914, Nilssonia Brongniart, 1825, Pterophyllum Brongniart, 1828 e Geinitzia Endlicher, 1847 possono essere dubitativamente segnalati per questa flora. Un numero consistente di generi segnalati per il Giurassico della Sardegna sono noti sia nella flora giurassica dello Yorkshire (Inghilterra) sia nelle altre flore giurassiche del territorio italiano, come ad esempio presso la località di Rotzo, in Veneto.

A palaeoenvironmental reconstruction of the Middle Jurassic of Sardinia (Italy) based on integrated palaeobotanical, palynological and lithofacies data assessment

During the Jurassic, Sardinia was close to continental Europe. Emerged lands started from a single island forming in time a progressively sinking archipelago. This complex palaeogeographic situation gave origin to a diverse landscape with a variety of habitats. Collection- and literature-based palaeobotanical, palynological and lithofacies studies were carried out on the Genna Selole Formation for palaeoenvironmental interpretations. They evidence a generally warm and humid climate, affected occasionally by drier periods. Several distinct ecosystems can be discerned in this climate, including alluvial fans with braided streams (Laconi-Gadoni lithofacies), paralic swamps and coasts (Nurri-Escalaplano lithofacies), and lagoons and shallow marine environments (Ussassai-Perdasdefogu lithofacies). The non-marine environments were covered by extensive lowland and a reduced coastal and tidally influenced environment. Both the river and the upland/hinterland environments are of limited impact for the reconstruction. The difference between the composition of the palynological and palaeobotanical associations evidence the discrepancies obtained using only one of those proxies. The macroremains reflect the local palaeoenvironments better, although subjected to a transport bias (e.g. missing upland elements and delicate organs), whereas the palynomorphs permit to reconstruct the regional palaeoclimate. Considering that the flora of Sardinia is the southernmost of all Middle Jurassic European floras, this multidisciplinary study increases our understanding of the terrestrial environments during that period of time.

Pennsylvanian floras from Italy: an overview of the main sites and historical collections

The paper provides an overview of the main Pennsylvanian sites in Italy yielding associations rich in plants and/or palynomorphs. So far in Italy, the principal outcrops are located in the Southern Alps, Tuscany and Sardinia. In the Western Southern Alps and bordering Switzerland, Westphalian outcrops are small and scattered. Nevertheless they yielded an abundant fossil flora, stored at the Museo Civico di Storia Naturale of Milan-, (Venzo and Maglia Collection). In the Carnic Alps-, (Eastern Southern Alps)-, continental deposits of Moscovian to Gzhelian age also occur near the border with Austria. They have produced a high number of preserved plant fossils, presently stored in the Museo Friulano di Storia Naturale of Udine. In Tuscany, the two main sections yielding Westphalian to Autunian floras are those of the Iano and Pisani Mountains. A rich collection of plant fossils from those sites is hosted at the Museo di Storia Naturale of Florence University and at the Museum of Natural History of Pisa University. In Sardinia, plant fossil sites are located in the south west and central east parts of the island. The San Giorgio Basin (Iglesiente subregion) and the Tuppa Niedda section (Arburese subregion) are late Westphalian – early Stephanian in age. In the Barbagia at Seui-Seulo and the Gerrei subregions, other continental basins yielded transitional “Stephanian- Autunian” fossil plant associations. The slabs are stored as part of the Lovisato Collection at the Lovisato Museum of the Chemical and Geoscience Department of Cagliari University. Smaller historical outcrops of Carboniferous age are also known from other Italian regions, such as Liguria.

Palaeontologic and biogeochemical characterization of the Cyrtograptus lundgreni event in the black shales of eastern Mid-Sardinia, Italy

A succession of biotic and geochemical changes that occurred during the Cyrtograptus lundgreni Event (Late Wenlock) have been recorded from the ‘pelagic’ black-shales in the Goni section, eastern mid-Sardinia, Italy. The studied interval encompasses the Cyrtograptus rigidus to Pristiograptus dubius-Gothograptus nassa zones. The fossil association includes graptolites, chitinozoans and microplankton i.e. probable linings of agglutinated foraminifera and radiolaria capsular membranes. Analysis of the chitinozoan distribution revealed a succession of several chitinozoan associations with low species diversity and dominated by opportunistic species. Three chitinozoan faunal turnovers and three extinction events have been recorded. Two of them coincide with graptolite extinctions whereas one probably is of local significance. Disappearance of the chitinozoan and microplankton associations occurred during four consecutive graptolite zones. Geochemical data (trace elements analysis) showed significantly higher (up to c. 100%) values for Co and Cd in the sedimentary organic matter (SOM) than in the whole rock samples. Possible relationships between peaks of metal enrichment, the major faunal changes among chitinozoans, extinction events among chitinozoans and graptolites and, to a certain extent, oceanic events may be inferred. The first extinction datum is older that those occurring in Gotland, Sweden and Thuringen, Germany and is so far considered to be of local significance. The second extinction datum of Sardinia can be matched with Datum 1 of Gotland and Thuringen. A close correlation between the third extinction datum of Sardinia and Datum 2 of Thuringen and Gotland reinforces the importance of these events at global scale.

New insights into the Middle Jurassic floras of Sardinia (Italy) - The Miccolis Collection at the Museo di Storia Naturale of Venice, Italy

The fossil plants of the Domenico Miccolis Collection, stored at the Museo di Storia Naturale of Venice (Italy), are from the Middle Jurassic Genna Selole Formation of central Sardinia. The assemblage contains 11 taxa: Marattia intermedia, Phlebopteris muensteri, P. braunii, Coniopteris sp. cf. C. hymenophylloides, Dicksonia kendallii, Eboracia sp. cf. E. lobifolia, Cladophlebis sp., Weltrichia sp. cf. W. whitbiensis, Geinitzia divaricata, Brachyphyllum expansum and Carpolithes sp. 2. Six species are described for the first time from the Jurassic strata of Sardinia (and Italy), thus increasing the known biodiversity of the flora of this age from these regions. The newly identified taxa have several characters in common with the well-studied Yorkshire flora (UK) indicating strong floristic affinities between southern and western Europe during the Jurassic.

A palynological investigation of funerary urn contents from the Roman Imperial age necropolis in Sardinia, Italy

This article presents the findings obtained from a palynological analysis of ashes contained in mortuary urns excavated in a necropolis in south Sardinia, Cagliari, Italy that dates back to the Roman Imperial age (1st century BC—4th century AD). The pollen content in the urns is mainly referable to the natural environment of the burning site and suggests that local vegetation was from a clearing characterised by dry saline soils. Data suggest that burning rituals were carried out near wet and saline environments, since chenopods (Salsola and Arthrocnemum) are constant elements in the mortuary ashes examined. Cremations would have occurred far away from the settlement areas, probably in local places in the marshy area located to the west and east of the necropolis and the Roman urban settlement. In general, the pollen content of the flowering plants retrieved points to the season when the funeral ceremonies occurred. The presence of charred conifer pollen grains, and the absence of suitable pieces of charred wood, suggests that the funeral pyres were probably built using conifer wood. Through this research, a complementary methodology of investigation in the field of environmental archaeology was tested.

Mineralogical, petrographic, and physical investigations on fossiliferous middle Jurassic sandstones from central Sardinia (Italy) to define their alteration and experimental consolidation

In the present work, the mineralogical-petrographic and physical features of Middle Jurassic sandstones with macrofossil plant remains belonging to the Domenico Lovisato collection, housed at the Geological and Palaeontological Museum of the Cagliari University (Sardinia, Italy), have been studied to define the alteration processes and the consolidating treatment. These sandstones, coming from the Genna Selole formation (central Sardinia), show evident problems of physical decay, due to petrophysical and compositional characteristics such as high porosity, low cementing degree, and presence of clay minerals (e.g., phyllosilicates). This latter leads to subsequent cyclic mechanisms of hydration/dehydration, which affect these sedimentary rocks. For this purpose, five main different sandstone specimens with evident crystalline matrix decohesion have been selected and analyzed. To define their mineralogical-petrographic (composition, microstructure) and physical characteristics (real and bulk densities, helium porosity, water absorption, mechanical strength, etc.), the optical microscope (OM) in polarized light, X-ray powder diffraction analysis (XRPD), helium and water pycnometer, and point load test were used. Testing the most suitable and compatible products for consolidation and time-saving of the palaeobotanical remains, several experimental treatment tests have been performed using four chemical products (i.e., alkoxysilane ethyl silicates and Na/K-silicate).

Past environments of Sardinian archaeological sites (Italy, West Mediterranean Sea), based on palynofacies characterization

Abstract A study method based on characterization of palynofacies (organic matter, palynomorphs) preserved in sediments was applied to obtain information about past environments of Sardinian sites. Organic matter (OM) was classified in ten categories according to its biological source, ecological characteristics, morphology and preservation state. These categories included woody and non-woody particles (cuticles, amorphous organic matter), phytoclasts, spores and pollen grains, gelified particles, and altered phytoclasts that ranged from transparent to opaque fragments. Cluster analysis classified the samples into associations. Each cluster includes stations with a similar spatial distribution pattern. The characterization of the different types of OM was coupled with palyno-logical analyses to produce suggested hypotheses about past vegetation, human activity and land use in Sardinia.

Middle Pennsylvanian vegetation of the San Giorgio Basin, southern Sardinia (Italy)

The small, intramontane San Giorgio Basin in southwestern Sardinia has yielded plant macrofossils dominated by sphenophytes, but with subsidiary pteridosperms, ferns, (?)noeggerathians and cordaitanthaleans. They belong to the upper part of the Crenulopteris acadica Zone or possibly the Odontopteris cantabrica Zone, indicating a late Asturian or Cantabrian (≡ late Moscovian) age. They therefore correlate with the post-Leonian deposits in northern Spain, the Nýřany Member in Western and Central Bohemia, and the Llantwit Beds in South Wales. The presence of post-tectonic deposits of this age is further evidence of the widespread influence of the Leonian Phase of tectonic activity in middle Asturian times, whose effect can be observed across Europe. The San Giorgio Basin is therefore a late Variscan rather than post-Variscan basin.