Davide Bassi

Coralline algal facies and their palaeoenvironments in the Late Eocene of Northern Italy (Calcare di Nago, Trento)

SummaryThe Calcare di Nago is a carbonate unit of Middle-Late Eocene (Bartonian and Priabonian) age which is well exposed at the north-eastern end of Lake Garda, on the western margin of the Lessini Shelf (Southern Alps). This unit is highly fossiliferous as far as the coralline red algae and large foraminifera are concerned. Corals, bryozoans, echinoderms, and molluscs are also present. The present study deals with the relationships among the coralline taxa, the coralline growth-forms, and their facies development in the Priabonian part of the type section of the Calcare di Nago. The taxonomic investigation led to the identification of 15 coralline red algal species belonging to 7 non-geniculate and 2 geniculate genera. One species of Peyssonneliacean (red alga) and one of Halimedacean (green alga) were also recognized. The quantitative and qualitative analyses based on coralline red algae and large foraminifera enabled five facies to be distinguished: Algal crust-branch rudstone, Algal/Discocyclina packstone, Coralalgal boundstone, Rhodolith mound wacke/packstone, and Rhodolith pavement. According to the coralline assemblages, coralline growth-forms, and large foraminiferal associations, the five facies reflect solid and soft substrate types. Some of these facies are dominated byin situ rhodoliths, others by reworked algal debris. In the architecture of an interpreted prograding carbonate ramp, shallow water facies are dominated by members of the subfamily Mastophoroideae, while deeper water facies are dominated by those of the subfamily Melobesioideae and family Sporolithaceae. There is a significant increase both in size and in constructional voids of the rhodoliths with depth. A concomitant decrease in algal species diversity with depth has been also recognized. LargeDiscocyclina assemblages are localized across the inner and mid ramp boundary.Pellatispira andBiplanispira are present only in the uppermost mid-ramp.Nummulites, Assilina, andSpiroclypeus are dominant together with small orthophragminids both in the mid- and uppermost outer ramp facies.

Microfacies analysis and palaeoenvironmental interpretation of Lower Oligocene, shallow-water carbonates (Gornji Grad Beds, Slovenia)

SummaryThe microfacies and palaeoenvironment of Lower Oligocene carbonates of the Gornji Gradbeds from Slovenia are investigated. These beds form part of a transgressive succession overlying both terrigenous sediments (sand-stones and conglomerates) and marine carbonates of Eocene age as well as transgressing directly over Triassic lime-stones. They are followed by foraminiferal rich marls. The carbonates were investigated using multivariate statistical techniques on point counts of thin sections. They are dominated by poorly sorted biogenic rudstones with pack-/wackestone matrix; pack- and grainstones are subordinate. The biogenic components of the carbonates are dominated by coralline red algae (9 genera with 11 species), corals, small benthic, large benthic, and encrusting foraminifera as well as bivalves. Gastropods, bryozoans, brachiopods, echinoderms, serpulids, and green algae are subordinate. The well preserved components allow details pertaining to taxonomy, growth-forms and taphonomic features to be observed. The following carbonate facies are distinguished: 1) nummulitic, 2) bivalve, 3) foraminiferal—coralline algal, 4) grainstone, 5) coralline alga, 6) coralline algal—coral, and 7) coral facies. All the carbonate facies represent fully marine conditions within the photic zone. They are interpreted with respect to substrate composition and stability, water turbulence, terrigenous input and light.

Diversity, growth forms and taphonomy: key factors controlling the fabric of coralline algae dominated shelf carbonates

Abstract The fabric of biogenic carbonate sediments can be differentiated (1) with respect to diversity of constituent components, (2) using features pertaining to their growth forms and (3) upon consideration of taphonomic aspects. These not only determine limestone fabrics, but also form the basis for facies differentiation and palaeoecological interpretation. This study is based on coralline algae dominated Lower Oligocene shelf carbonates from northern Slovenia from which seven facies (nummulitic, bivalve, foraminiferal-coralline algal, coralline algal, coralline algal-coral, coral and grainstone) are differentiated. The role of diversity, growth forms and taphonomy of coralline algae in each facies is discussed. Nine species from seven genera of coralline algae including geniculates and non-geniculates were recognized. Numerous different growth forms ranging from crusts, protuberances, lamellae to arborescent types are present. A wide range of taphonomic features including disarticulation, encrustation, fragmentation and abrasion can be observed. The determination of diversity is dependent on taxonomic identification using preserved diagnostic characters relevant to palaeontological and botanical systematics. Growth-form determination in thin section is influenced by orientation and sectioning effects. The taphonomy of red algae is highly dependent on initial growth form and the specific environment in which they are found. A number of taphonomic processes described in Recent environments (e.g. disease, shallow grazing) cannot be ascertained in fossil material, while others are readily observable. Some taphonomic processes are detrimental (e.g. fragmentation, abrasion) to the preservation and recognition of vegetative and growth-form features, while others have positive effects (e.g. encrustation).

Tracking paleoenvironmental changes in coralline algal-dominated carbonates of the Lower Oligocene Calcareniti di Castelgomberto formation (Monti Berici, Italy)

Lower Oligocene, shallow-water carbonates of the Calcareniti di Castelgomberto formation (Monti Berici, Italy, Southern Alps) are studied in detail with respect to fabric and component distributions in order to trace paleoecological changes along a monotonous sedimentary stacking pattern. The carbonates are dominated by coralline algal rudstones with a packstone to wackestone matrix. Non-geniculate coralline algae include six genera: Lithoporella melobesioides, Mesophyllum, Neogoniolithon, Spongites, Sporolithon, and Subterraniphyllum. The algae are found in the form of encrusting thalli, rhodoliths, and coralline debris. Non-algal components include larger, small benthic, and planktonic foraminifera associated with bryozoans, zooxanthellate corals, and echinoderms. Four carbonate facies are distinguished: (1) coralline algal facies, (2) coralline algal-coral facies, (3) coralline algal-larger foraminiferal facies, and (4) coralline algal debris facies. Marly horizons also occur in the section. The facies and coralline algal content are interpreted with respect to light intensity, hydrodynamic energy, biotic interactions, and substrate stability. Facies development along the studied section shows systematic variations, suggesting asymmetric sea-level changes with rapid regressions and gradual transgressions.

Rhodalgal/bryomol assemblages in temperate-type carbonate, channelized depositional systems: the Early Miocene of the Sarcidano area (Sardinia, Italy)

Abstract During Aquitanian-Burdigalian times, temperate-type carbonate-siliciclastic successions were deposited in basins located on the graben and half-graben along the Oligo-Miocene Sardinia Rift Basin (Sardinia, Italy). In one of these basins, the Isili Basin, rhodalgal/bryomol limestone was deposited in a temperate-type carbonate depositional system in which a shallow carbonate factory, a marginal tributary belt and a main channel were identified. In this paper, the Isili Limestone is described in terms of biogenic components and taphonomic characterization. To understand the palaeoecology of the depositional settings and the related palaeoceanographic controls, the coralline algal assemblages were differentiated according to coralline growth forms, rhodolith shapes, rhodolith inner structure and taxonomic composition. In addition, a first analysis was carried out in order to discriminate among the different bryozoan and mollusc assemblages present in different localities corresponding to different palaeoecological settings. The results obtained provide fundamental support for palaeoenvironmental reconstruction that combines palaeobiological analyses (i.e. rhodolith characteristics, bryozoan growth forms, taphonomic features) with previous physical (sedimentological and geometrical) observations. This allows a more detailed reconstruction of the complex relationships between the different sectors of the sedimentary system: the carbonate factory, the smaller erosive tributary channels and the deeper main channel.

CALCAREOUS ALGAE FROM THE LOWER OLIGOCENE GORNJI GRAD BEDS OF NORTHERN SLOVENIA

This paper presents the first systematic account of calcareous algae from the limestones of the Lower Oligocene Gornji Grad beds of northern Slovenia. These bioclastic limestones are dominated by different coralline algal assemblages as well as corals, large and small benthic foraminifera as well as bivalves. The taxonomy and growth-forms of eleven species of seven non-geniculate coralline algal genera are described: Lithoporella , Neogoniolithon , Spongites , Lithothamnion , Mesophyllum , Sporolithon , Subterraniphyllum ,. Additionally, the genera Polystrata (Peyssonneliaceae) Halimeda ( Halimeda ceae), and Cymopolia (Dasycladaceae) are present. The taxonomic interpretation of fossil coralline material in a manner consistent with generic and specific concepts currently in use for Recent material is, at present, difficult. In the absence of comparative studies on type material, only limited comparisons are possible, and in most cases definitive taxonomic conclusions cannot be reached. Most of the species designations are thus made following and open nomenclature, pending the rigorous taxonomic revision of historically established, fossil coralline algal species. The present study reveals a considerable variation of growth-form morphologies at both genus and species levels. This demonstrates the difficulties in using this feature as a diagnostic character in the identification of fossil coralline red algal taxa.

An Early Jurassic oligohaline ostracod assemblage within the marine carbonate platform sequence of the Venetian Prealps, NE Italy

Boomer, I., Whatley, R., Bassi, D., Fugagnoli, A., Loriga, C. (2001). An Early Jurassic oligohaline ostracod assemblage within the marine carbonate platform sequence of the Venetian Prealps, NE Italy. Palaeogeography Palaeoclimatology Palaeocology, 166(3-4), 331-344.

Microtaphofacies: Exploring the Potential for Taphonomic Analysis in Carbonates

The microtaphofacies of Paleogene carbonates from three time units (Middle Eocene, Late Eocene and Early Oligocene) from the circumalpine area are described and compared. These carbonates are dominated by various larger foraminiferal and coralline red algal facies with subordinate coral and bryozoan facies.

Typification and reassessment of seventeen species of coralline red algae (Corallinales and Sporolithales, Rhodophyta) described by W. Ishijima during 1954–1978

Type specimens of 17 species of non-geniculate coralline red algae belonging to the Corallinales and Sporolithales (Corallinophycidae, Rhodophyta) and established between 1954 and 1978 by Wataru Ishijima have been re-examined, focusing on characters relevant to modern coralline taxonomy. The species are from the Early Cretaceous, Eocene, Oligocene, Miocene and Pleistocene rocks of southern and central Japan, Indonesia, Malaysia, Indian Ocean, Philippines, Pakistan and the Galapagos Archipelago, and were attributed by Ishijima to Lithothamnion (as Lithothamnium), Mesophyllum, Lithophyllum and Archaeolithothamnion (as Archaeolithothamnium). With two exceptions, all species are reassigned to different genera or are of uncertain generic placement within particular subfamilies, families or orders. The type specimen of Lithophyllum oboraensis is retained in Lithophyllum and the type specimen of Mesophyllum izuensis is retained in Mesophyllum. The type specimens of Lithophyllum izuensis (Ishijima) comb nov. (= Lithothamnion izuensis), Phymatolithon tokumanensis (Ishijima) comb. nov. (= Mesophyllum tokumanensis), Sporolithon borneoensis (Ishijima) comb. nov. (= Archaeolithothamnium borneoense) and Sporolithon galapagosensis (Ishijima) comb. nov. (= Archaeolithothamnion galapagosensis) possess features justifying their assignment to various genera within a particular family and subfamily. A specimen ascribed by Ishijima to Archaeolithothamnion galapagosensis (as Archaeolithothamnium) in the protologue of that species is a misidentified specimen of Sporolithon ptychoides Heydrich. The type specimens of Lithophyllum minoensis and Mesophyllum indicum belong to the Corallinaceae, subfamily Mastophoroideae but are of uncertain generic placement. The type specimens of Lithothamnion makinogoensis, L. nodai, L. tenuicrustatum, Mesophyllum niinoi and M. yuyashimaensis belong to the Hapalidiaceae (Melobesioideae) but are of uncertain generic placement. The type specimens of Lithophyllum hashimotoi, Lithophyllum minae, Lithothamnion huseinii and Lithothamnion tokiensis lacked sufficient data to allow for order, family, subfamily or genus placement within the Corallinophycidae. Lectotype specimens have been designated as necessary, and relevant historical, repository, geological, morphological and other data are presented.

Paleogene larger rotaliid foraminifera from the western and central Neotethys

Part I The rotaliid foraminifera 1 Rotaliid shell architecture and the palaeodiversity of the Lockhartia Sea 1.1 Lamellation theory (Smout 1954 Hansen 1999) 1.2 Elements of rotaliid architecture 1.3 Life strategies: an overview 1.4 Cyclical community maturation 1.5 Diversity in the Lockhartia Sea 2 The system of the Rotaliidae, an overview 2.1 Overview 2.2 Superfamily Rotaliacea Ehrenberg: family Rotaliidae Ehrenberg, 1839 2.3 Identification key to the Paleogene genera of the superfamily Rotaliacea 2.4 Identification key to some genera excluded from the Rotaliacea 2.5 Identification key for some rotaliids with single foramina and lacking umbilical plugs or umbos 2.6 Identification key for some rotaliid shells with multiple areal foramina 2.7 Identification key for some rotaliid shells of the family Victoriellidae Part II Systematic palaeontology: Family Rotaliidae 3 Subfamily Rotaliinae Ehrenberg, 1839 3.1 Rotorbinella Bandy, 1944 3.2 Pyrenorotalia Boix et al., 2009 3.3 Rotospirella n. gen. 3.4 Rotalia Lamarck, 1804 3.5 Medocia Parvati, 1971 4 New subfamily Redmondininae 4.1 Redmondina Hasson, 1985 4.2 Slovenites n. gen. 4.3 Rotaliconus Hottinger, 2007 4.4 Pachyrotalia n. gen. 5 New subfamily Lockhartiinae 5.1 Rotalispira n. gen. 5.2 Lockhartia Davies, 1932 5.3 Dictyoconoides Nuttall, 1925 5.4 Sakesaria Davies, 1937 5.4.1 Additional species or varieties of Sakesaria 6 New subfamily Kathininae 6.1 Kathina Smout, 1954 6.2 Dictyokathina Smout, 1954 6.3 Plumokathina n. gen. 7 New subfamily Daviesininae 7.1 Daviesina Smout, 1954 8 Some taxa that are or remain excluded from the family Rotallidae 8.1 Neorotalia Bermundez, 1952 8.2 Paralockhartia n. gen. 8.3 New subfamily Laffitteininae 8.3.1 Laffitteina Marie, 1946 8.3.2 Cuvillierina Debourle, 1955 8.3.3 Smoutina Drooger, 1960 8.3.4 Storrsella Drooger, 1960 9 Rotaliid taxa with uncertain affinities 9.1 Rotaliid taxa without umbilical fills 9.1.1 Thalmannita Bermundez, 1952 9.1.2 Civrieuxia Bermundez, 1978 9.2 Rotaliid taxa with multiple foramina 9.2.1 Scarificatina Moorkens, 1982 9.2.2 Cincoriola Haque, 1958 9.2.3 Rahaghia n. gen. 9.3 Some rotaliids of the family Victoriellidae Chapman and Crespin, 1930 9.3.1 Gyroidinella Le Calvez, 1949