Facies of Liassic sponge mounds, central High Atlas, Morocco

Summary Liassic sponge mounds of the central High Atlas (Rich area, northern Morocco) have a stratigraphic range from the Lower/Upper Sinemurian boundary interval up to the lower parts of the Lower Pliensbachian (Carixian). The base of Liassic sponge mounds consists of a transgressive discontinuity, i.e., a condensed section of microbioclastic wackestones with firm- and hardgrounds, ferruginous stromatolites, sponge spicules and ammonites. The top of Liassic sponge mounds is an irregular palaeorelief covered by cherty marl-limestone rhythmites, namely hemipelagic spicular wackestones with radiolaria. In the Rich area, section Foum Tillicht, the sponge mound succession has a total thickness of about 250 meters. Within this succession we distinguished between three mound intervals. The lower mound interval shows only small, meter-scale sponge mounds consisting of boundstones with lyssakine sponges, commensalicTerebella and the problematicumRadiomura. This interval forms a shallowing-upward sequence culminating in a bedded facies withTubiphytes, calcareous algae (Palaeodasycladus), sponge lithoclasts, coated grains, and thin rims of marine cement. The middle mound interval is aggradational with decametric mounds and distinct thrombolitic textures and reefal cavities. The mound assemblage here consists of hexactinellid sponges, lithistid demosponges, non-rigid demosponges,Radiomura, Serpula (Dorsoserpula), Terebella, encrusting bryozoa, and minor contributions by calcareous sponges, and excavating sponges (typeAka). Thrombolites are dendrolitic and may reach sizes of several tens of centimeters, similar to the maximum size of siliceous sponges. The upper mound interval appears retrogradational and geometries change upsection from mound shapes to flat lenses and level-bottom, biostromal sponge banks. The biotic assemblage is similar to that of the middle mound interval and there is no difference between mound and bank communities. The demise of sponge mounds is successive from regional spread in the Sinemurian to more localised spots in the Lower Pliensbachian. This reduction correlates with an increasing influence of pelagic conditions. At Foum Tillicht, sponge mounds lack any photic contribution and there is virtually no differentiation into subcommunities between mound surface and cavity dwelling organisms. There is some evidence that the heterotrophic food web of mound communities was sourced by oxygen minimum zone edge effects, namely microbial recycling of essential elements such as N and P. Basin geometry suggests a waterdepth of several 100's of meters, well below the photic zone and possibly only controlled by the depth range of the oxygen minimum zone. Palaeoceanographic conditions of well-stratified deeper water masses diminished gradually during widespread transgression across the Sinemurian to Pliensbachian boundary culminating in the Lower Pliensbachianibex ammonite zone.     

Platform-basin transect of a middle to late Jurassic large-scale carbonate platform system (Shotori mountains,Tabas area,east-central Iran)

Summary Following a phase of predominantly siliciclastic sedimentation in the Early and Middle Jurassic, a large-scale, low-latitude carbonate depositional system was established in the northern part of the Tabas Block, part of the central-east Iranian microplate, during the Callovian and persisted until the latest Oxfordian/Early Kimmeridgian. Running parallel to the present eastern block margin, a NNW/SSE-trending carbonate platform developed in an area characterized by reduced subsidence rates (Shotori Swell). The growth of this rimmed, flat-topped barrier platform strongly influenced the Upper Jurassic facies pattern and sedimentary history of the Tabas Block. The platform sediments, represented by the predominantly fine-grained carbonates of the Esfandiar Limestone Formation, pass eastward into slope to basin sediments of the Qal'eh Dokhtar Limestone Formation (platform-derived allochthonites, microbialites, and peri-platform muds). Towards the west, they interfinger with bedded limestones and marlstones (Kamar-e-Mehdi Formation), which were deposited in an extensive shelf lagoon. In a N−S direction, the Esfandiar Platform can be traced for about 170 km, in an E-W direction, the platform extended for at least 35–40 km. The width of the eastern slope of the platform is estimated at 10–15 km, the width of the western shelf lagoon varied considerably (>20–80 km). During the Late Callovian to Middle Oxfordian, the Esfandiar Platform flourished under arid climatic conditions and supplied the slope and basinal areas with large amounts of carbonates (suspended peri-platform muds and gravitational sediments). Export pulses of platform material, e.g. ooids and aggregate grains, into the slope and basinal system are interpreted as highstand shedding related to relative sealevel variations. The high-productivity phase was terminated in the Late Oxfordian when the eastern platform areas drowned and homogeneous deep water marls of the Upper Oxfordian to Kimmeridgian Korond Formation onlapped both the Qal'eh Dokhtar Limestone Formation and the drowned Esfandiar Limestone Formation. Tectonic instability, probably caused by faulting at the margins of the Tabas Block in connection with rotational movements of the east-central Iranian block assemblage, was responsible for the partial drowning of the eastern platform areas. In some areas, relicts of the platform persisted to produce shallow-water sediments into the Kimmeridgian.     

Paleoenvironmental model for Eocene foraminiferal limestones of the Adriatic carbonate platform (Istrian Peninsula)

The foraminiferal limestones from the Middle Eocene Central Istrian region illustrate progressive deepening of depositional gradients. Shifting of Lower Cuisian to Upper Lutetian microfacies can be described in terms of a ramp model. The Orthophragminae-bearing parts of the foraminiferal limestones are interpreted in terms of larger foraminiferal faunal associations, planktonic foraminiferal relative abundance, limitations of algal endosymbionts, foraminiferal lamellar thickness and flattening of test shapes. Microfacies I contains the most diverse larger foraminiferal association with a predominance of large, thick nummulitids, assilinids, and asterocyclinids. Microfacies II is characterized by a gradual increase of Orthophragminae diversity and abundance. Nummulitids, equally abundant, are dominated by lenticular and subspherical specimens. The reduction in number of nummulitid specimens with characteristic biconical radiate morphologies, and relative abundance of flattened orthophragminids, characterizes Microfacies III. Scattered biodestructed orthophragminid tests and planktonic foraminifera constitute Microfacies IV, indicating the end of a long-lasting, shallow-marine Adriatic Carbonate Platform regime.     

Toarcian ammonites of the Polymorphum Zone,Amellago area (eastern central High Atlas), Morocco,with a discussion on ammonite turnover events

In the Amellago area (central High Atlas), the widely distributed Toarcian succession consists of marls and marly limestones of the Tagoudite and Agoudim formations. We here describe, for the first time, the ammonites of the Polymorphum Zone from the Tagoudite Formation, including Canavaria cf. rosenbergi Fucini, C. aff. zancleana (Fucini), Dactylioceras (Eodactylites) mirabile (Fucini), D. (E.) aff. mirabile (Fucini), D. (E.) pseudocommune Fucini, D. (E.) simplex (Fucini), D. (Orthodactylites) aff. crosbeyi (Simpson), Lytoceras gr. villae Meneghini, Neolioceratoides cf. hoffmanni (Gemmellaro) and Praepolyplectus sp. This ammonite assemblage is closely correlated with those reported from the Polymorphum Zone of several basins of the Tethyan margins and the Northwest European Subboreal Realm, indicating marine communications between the different Moroccan Jurassic basins and the central Atlantic trough. The overlying Agoudim Formation yields ammonites of the Levisoni Zone in its base and rare ammonites of the Bifrons Zone in the middle part. Four significant changes in the ammonite assemblages during the early-middle Toarcian and their probable causes are also discussed.     

Recent dynamics of the wet pastures at Oukaimeden plateau (High Atlas mountains, Morroco)

Wetlands are a very important universal heritage; in the Moroccan High Atlas mountains the geomorphology and the slopes evolution determine the existence of the numerous projecting ledges of pozzines on plateaus and oozing. This is particularly the case in Oukaimeden site located at 75 km south of Marrakesh. These wet grasslands have been developed on small surface areas supported by soils water accumulation; and close to the sources and on some banks constitute wetlands of high floristic richness, which makes them very coveted pastures by local populations. These wet pastures are highly sensitive to climatic factors. Recent climatic changes, the anthropic and pastoral pressures and the global environmental changes, affect these zones at the level of their structure (areas, soil characteristics…) and their ecological functions. In the Oukaimeden plateau, the use of aerial photography made it possible to carry out a detailed follow up of the hydraulic adjustments (dam construction in the 1970s) as well as the setting up of new adjustments (tracks, paths, drain channel) on the structure and functioning of these grasslands.     

Toe-of-slope deposits of a Givetian reef-rimmed platform: provenance of calcareous density-flow deposits (Rabat-Tiflet-Zone,Morocco)

Givetian subaqueous density-flow deposits reveal the existence of a peritidal carbonate platform in sedimentary basins preserved within the Rabat-Tiflet-Zone of Morocco. The calcareous component assemblage displays a photozoan carbonate production mode of the neritic source environments. Characteristic elements of the allochthonous faunal association are colonial tabulate corals, stromatoporoids, crinoids, bryozoans and thick-shelled brachiopods. Active growing reefs and cortoid sand shoals at the platform margin as well as periplatform carbonates at the uppermost slope settings contributed bioclastic and lithoclastic lime debris to the toe-of-slope of the carbonate apron. Bipartite cobble rudstone beds are interpreted as deposits of hyperconcentrated density flows, which cannot be maintained on very low-angle slopes for as long as more dilute flows and represent short run-out distances. Beds consisting of mostly well-organized pebbly grainstones, packstones and grainstone-wackestone couplets are deposits of surge-like concentrated flows and turbidity flows.     

The reefal margin and slope of a Middle Triassic carbonate platform: the Latemar (Dolomites, Italy)

The Latemar is a mainly aggrading platform, but shows repeated backstepping during its entire development. The behaviour of the slope does not reflect accommodation changes and lateral consistencies of the lagoonal interior; the Latemar contemporaneously reveals different, even contrasting depositional characteristics. The slope of the late stage platform evolution corresponds at least partially to the base-of-slope apron model. Controlling factors on slope evolution are of tectonic (proximity of the Stava Line) and autocyclic (repeated oversteepening) nature. Other factors are insignificant and/or overprinted. The reef-facies at Latemar reveals a complex facies pattern; it varies along and across the margin and is rich in encrusting sponges, corals, biogenic crusts and Microproblematica. Some biota or fossil assemblages—e.g. foraminifers (Abriolina mediterranea, Turriglomina scandonei) or Tubiphytes multisiphonatus thrombolites—have not been described in the Dolomites before. Biostratigraphic evidence from the uppermost reef-facies confirms a mainly Anisian age of the outcropping platform interior.     

Facies of a Lower Ordovician carbonate shelf (Mungok Formation: Taebaeksan Basin,Korea)

Summary The lithologic associations within the Lower Ordovician Mungok Formation in Korea define four depositional facies that formed across a continental margin fringing the Sino-Korean block: these facies represent lagoonal/restricted marine, shoal, inner shelf, and outer shelf environments. The stacking pattern of these facies reveals two systems tracts composed of five depositional sequences. The lower highstand systems tract consists of the lagoonal/restricted marine and shoal facies, whereas the upper lowstand systems tract comprises, in ascending order, inner shelf, outer shelf, and inner shelf facies. Three trilobite biofacies are recognized in the Mungok Formation: i.e.,Yosimuraspis, Kainella, andShumardia biofacies in ascending order. TheYosimuraspis Biofacies is dominated byYosimuraspis but also containsJujuyaspis andElkanaspis. The predominance of the endemic eponymous taxon suggests a lagoonal/restricted marine environment. The nearly monotaxicKainella Biofacies, which comprises pandemic genera such asKainella and occasionallyLeiostegium, may represent a less restricted environment than theYosimuraspis Biofacies. TheShumardia Biofacies occurs in the marlstone/shale lithofacies through relatively thick stratigraphic interval and is dominated by cosmopolitan trilobite taxa with some endemic species. The lithofacies and cosmopolitan trilobite assemblage of theShumardia Biofacies indicate that it occupied an outer shelf environment. The vertical succession of lithofacies and trilobite biofacies in the Mungok Formation records in general a shift from a restricted, shallow water environment to deeper-water environment.     

Toarcian carbon isotope shifts and nutrient changes from the Northern margin of Gondwana (High Atlas, Morocco, Jurassic): Palaeoenvironmental implications

The Early Toarcian is marked by a global perturbation of the carbon cycle and major marine biological changes. These coincide with a general decrease in calcium carbonate production and an increase in organic carbon burial, and culminate in the so-called Toarcian Oceanic Anoxic Event. It is believed that the environmental crisis was triggered by the activity of the Karoo-Ferrar large igneous province. In order to further document the Early Toarcian palaeoenvironmental perturbations, carbon isotope, total organic matter, calcareous nannofossils and phosphorus content of the Amellago section in the High Atlas rift basin of Morocco were investigated. This section is extremely expanded compared to the well-studied European sections. Its position along the northern margin of the Gondwana continent is of critical importance because it enables an assessment of changes of river nutrient input into the western Tethyan realm. The carbon isotope curve shows two negative excursions of equal thickness and amplitude, at the Pliensbachian-Toarcian boundary and at the transition from the Polymorphum to the Levisoni Zone. This confirms the supra-regional nature of these shifts and highlights the possible condensation of the first “boundary” shift in European sections. Phosphorus content is used to trace palaeo-nutrient changes and shows that the two negative carbon isotope shifts are associated with increased nutrient levels, confirming that these episodes are related to enhanced continental weathering, probably due to elevated greenhouse gases in the atmosphere. In the High Atlas Basin, the increase in nutrient levels at the Pliensbachian-Toarcian boundary is moreover likely to be the main factor responsible for the coeval demise of the Saharan carbonate platform. A middle Toarcian event, centered on the boundary between the Bifrons and Gradata Zones, characterized by a positive carbon isotope excursion and nutrient level rise, is documented in the Amellago section.     

Microfacies controls on weathering of carbonate building stones: Devonian (northern Sauerland,Germany)

Summary The Beisinghausen Limestone (Upper Givetian to Frasnian) in the Eslohe-Reiste area (northern Sauerland), used in the past as building stone, corresponds to proximal carbonate turbidites which have been derived from the Attendom-Elspe ‘reef’ complex. The particles of this allodapic limestone originated in different parts of the carbonate complex as shown by facies-diagnostic microfossils (foraminifera, calcisphaeres, calcareous algae, microproblematica). The fossils as well as the other dominating grain types (lumps, peloids) point to source areas located within lagoonal and slope environments. Reef-derived material is rare. The turbidites exhibit four microfacies types, differentiated by composition and size of the grains as well as by micrite content and corresponding to the common vertical and lateral textural variation of limestone turbidites. These MF types were recognized in outcrops as well as from building stones used in building the St. Pankratius church in Eslohe-Reiste (northern Sauerland) in 1849 and in the renovation of the church in 1963/64. The comparison of microfacies and the degree of the destruction of ‘old’ and ‘new” building stones by weathering (macroscopically described by the ◂Fabric Index’: Product of the ‘Rock Destruction Risk’ and the ‘Rock Preparation Destruction Degree’) shows that intrabioclastic rudstones (MF type 1) and bioclastic grainstones (MF type 2), both characterizing the basal parts of the turbidite beds, are more resistant to weathering destruction originating from freezing and thawing than packstones (MF type 4). Weathering of micritic facies types (e.g., MF 4) is more intensive due to the stronger development of joint systems affecting not only the surface of the building stones but the entire dimension stone. Porosity or the existence and amount of stylolites seem to have had no significant impact on the weathering of the building stones studied. The stronger weathering of building stones used in the original construction of the church as compared with the stones applied in this century is caused by the greater time interval available for mechanical weathering connected with freezing and thawing. The consideration of microfacies of limestone turbidites should facilitate the exploitation of weathering-resistant carbonate building stones.     

Stratigraphy, geometry, and facies of a Middle Devonian ramp-to-basin transect (Eastern Anti-Atlas, SE Morocco)

Summary In the castern Anti-Atlas (SE Morocco), a small sedimentary basin (Mader Basin) evolved during the late Palacozoic. The Middle Devonian deposits consist of shales and limestones with a thickness up to 700 m in the depocentre. Sedimentary structures and sole marks of Middle Devonian limestones indicate transport from the northwest and the south towards the basin centre, located in the central Mader area. Lithostratigraphic, biostratigraphic, and dynamic stratigraphic approaches were applied to correlate stratigraphic sections. Five correlatable large-scale base-level hemicycles were recognized in the Middle Devonian succession. Thickness trends of Middle Devonian deposits, regional correlations, and facies-trends reveal the geometry of a carbonate ramp. The carbonate ramp was slightly inclined (<1°) to the NE. A sedimentary wedge, consisting of limestones and limestone/marl alternations, was deposited during the Eifelian and marks the transition from the ramp to the adjacent basin. Middle Devonian water depths are estimated as close to and within the storm wave-base at the southern area of the ramp and far below storm wave-base in the northeastern part of the ramp. Shallowest conditions (inner-ramp environment), close or within the fairweather wave-base, existed during the early Givetian as documented by the abundance of recfal fauna (stromatoporoids, corals) and calcimicrobes (lumps, micritic envelopes) in the eastern and southeastern area of the ramp.     

Aromatic,Medicinal Plants and Vulnerability of Traditional Herbal Knowledge in a Berber Community of the High Atlas Mountains of Morocco

This article compliments the S18 session (transmission of traditional ecological knowledge and conservation of medicinal plants) at the 13th International Congress of Ethnobiology (ISE) in Montpellier, France (May 2012). The aim of the article is to provide an insight into the livelihoods of a Berber community, a village of the High Atlas Mountains of Morocco, of the local biodiversity and most importantly, the prevalent use of medicinal plants for primary health care. It seeks to demonstrate the value of traditional ecological and herbal knowledge for the subsistence of the community and emphasises the vital role that family and community connections play for the transmission of traditional herbal knowledge within the community.     

Aromatic,Medicinal Plants and Vulnerability of Traditional Herbal Knowledge in a Berber Community of the High Atlas Mountains of Morocco

This article compliments the S18 session (transmission of traditional ecological knowledge and conservation of medicinal plants) at the 13th International Congress of Ethnobiology (ISE) in Montpellier, France (May 2012). The aim of the article is to provide an insight into the livelihoods of a Berber community, a village of the High Atlas Mountains of Morocco, of the local biodiversity and most importantly, the prevalent use of medicinal plants for primary health care. It seeks to demonstrate the value of traditional ecological and herbal knowledge for the subsistence of the community and emphasises the vital role that family and community connections play for the transmission of traditional herbal knowledge within the community.     

Filament lumachelle on top of Middle Jurassic oolite limestones: event deposits marking the drowning of a Tethysian carbonate platform (Subbetic,southern Spain)

Bioclastic accumulations often occur on top of Tethysian carbonate platforms and crinoids are a common constituent of these bioclastic deposits on Lower and Middle Liassic carbonate platforms. In contrast, the relevant literature contains few examples in which the main constituent of the lumachels is thin-shelled bivalves (filaments). This paper presents a study of a filament lumachelle cropping out on top of a Middle Jurassic carbonate platform. The carbonate platform is represented by the Jabalcuz Formation, found in one of the northernmost Subbetic units (south of Jaén city). The lumachelle marks the demise of the carbonate platform and has special features that characterize the drowning phase. This process has been related with the syn-rift extensional tectonics associated to the opening of the Tethys westwards. Stratigraphically, the lumachelle occurs on top of shallow-water oolite limestones (Middle Jurassic) and is overlain by radiolarian-rich pelagic and resedimented deposits (Latest Callovian–Oxfordian). It occurs as a body (about 1.5 km wide and up to 8 m thick) made up entirely of densely packed thin bivalve shells. A remarkable feature of the bivalve shell beds is stromatolite-like crumpled lamination at the outcrop. The observations made at the outcrop scale, by microscope under transmitted light, and by cathodoluminiscence favor a diagenetic origin for this striking structure. Other hypotheses, such as its possible relation with seismicity, cannot be confirmed. The filaments would have filled one of the former basins that originated in relation with syn-rift fault-block tectonics leading to the demise of the carbonate platform. Tectonics was one of the main factors setting in motion a carbonate productivity crisis and the inhibition of a diverse benthic community. Once production failed in the carbonate factory, storms and probably hurricanes as well, swept shell deposits from the shallowest areas of the shallow-water carbonate platform and accumulated them in a coevally formed small half-graben basin. At least three main depositional stages can be differentiated in the fill of this half-graben basin, which was a sediment trap for the accumulation and preservation of the tiny bivalve shells against ebb surges. The massive accumulation of valves, the shortage of micrite around the filaments, outcrop morphology and facies relationships, along with regional geology, are among the arguments supporting this interpretation.     

An example for black shale development on a carbonate platform (late Triassic, Seefeld, Austria)

Summary East of Seefeld/Tyrol the Hauptdolomit facies (Triassic, Norian) is accompanied by an organic-rich intercalation, the Seefeld facies. Three facies were distinguished, which developed within a separate basin within the Hauptdolomit carbonate platform. These facies have been investigated in an environmental and palaeoecological context applying microfacies analysis, palynology, organic petrology, organic geochemistry and stable isotope geochemistry. As the controlling factors of sedimentation, sea level changes are suggested for large scale fluctuations, and climatic changes for variations on a smaller scale. Within the basin facies a μm-scaled rhythm can be observed, which was obviously seasonally controlled. Amajor amount of organic material of the deposit has been produced by microbial activity under anoxic conditions. Causes for the absence of pollen and spores in many black shale deposits are discussed.     

Upper jurassic to lower cretaceous carbonate facies of african affinities in a Peri-European area: Chalkidiki Peninsula, Greece

Summary The Epanomi-New Iraklia area (West coast of the Chalkidiki peninsula) is considered to belong to the Prepeonias subzone (or Gevgeli unit), with a palaeogeographic position near the European margin, represented by the Serbo-Macedonian massif, and at a considerable distance from the fragmented African plate, the marginal block of which is here the Pelagonian Domain. In some boreholes in the area an Upper Jurassic to Lowei Cretaceous limestone sequence has been observed, ending with an unconformity and followed by an Upper Middle-Lower Upper Eocene transgressive bioclastic limestone, an Upper Eocene to Lower Oligocene clastic series and Neogene deposits. This Upper Jurassic to Lower Cretaceous carbonate platform sequence and probably the Upper Jurassic limestones with bauxites of the nearby Mt. Katsika, show African affinities, viz: the presence of the essentially Aptian algal speciesSalpingoporella dinarica, an African plate marker; the chlorozoan type association and the bauxite formation during the Late Jurassic indicating tropical conditions; finally, the chloralgal type association and the sporadic presence of radial-fibrous ooids during the Early Cretaceous indicating peritropical conditions. Lower Cretaceous limestones are apparently missing in the innermost Hellenides. In the Pelagonian Domain s.l., on the other hand, Upper Jurassic to Lower Cretaceous limestones are found in some places, with same characteristics as in the Epanomi-New Iraklia boreholes. On the contrary, the Upper Eocene to Lower Oligocene clastic series of the boreholes can be correlated with the Axios (=Vardar) molassic basin, inline with its present situation. During the Mesozoic, the Epanomi area therefore belonged to a micro-block, next to the NE margin of the Pelagonian Domain, in contrast to earlier interpretations. Its present time position results from Early Cenozoic tectonic phases.     

Applied microfacies analysis: Provenance studies of Roman mosaic stones

Summary Provenance analysis of archaeological materials is an essential tool of archaeometry but has been rarely applied to antique mosaics. Many mosaics are made of carbonate mosaic stones (tesserae). Hence, microfacies analysis offers a great potential in differentiating these limestone tesserae and provenancing their local, regional, imported or recycled origins. The methods of microfacies analysis and their prospects for studying mosaics are demonstrated by case studies of Roman mosaics from southern Germany (Kraiburg, Bavaria). Austria (Hemmaberg near Globasnitz, southern Carinthia), Italy (Asolo north of Padova) and late Punic and Roman mosaics from Tunisia (Carthage and Hergla). Microfacies-based provenance analysis comprises six stages: 1) Macroscopic assessment and definition of rock colour groups of tesserae, 2) Sampling based on rock-colour categories, 3) Definition of microfacies types and attribution to standard microfacies types based on thin-section criteria, 4) Evaluation of the mosaic site with respect to geological and paleontological data followed by comparisons of the microfacies inventory of the region with microfacies types of the tesserae, 5) Assessment of carbonate tesserae to specific geological rock/time units followed by suggestions of provenance sites. 6) Critical evaluation of provenance assessment within the archaeological context. Principal limestone colours do not necessarily coincide with specific limestone types. Uniformly coloured tesserae can represent different limestone types from different sources (cf. Kraiburg, Hemmaberg). On the other hand, a specific limestone type may be characterized by different rock colours (cf. Carthage). Provenance assessment of mosaic stones results in relatively narrow (Hemmaberg, Asolo) or only broad (Carthage, Hergla) indications of sites characterized by exposures of carbonate rocks whose microfacies criteria, geological age and rock colour correspond to those of the carbonate tesserae. The case studies argue for local and/or imported (Kraiburg) as well as regional provenances of the mosaic material (Hemmaberg, Asolo; source area within a distance between 10 and about 40 km) and indicate that off-cuts of building stones exploited within a regional frame might possibly have been used (Carthage). Differences in the composition and diversity of carbonate rocks used for the fabrication of mosaics reflect time-dependent changes in major quarrying and potential source areas (Carthage). Further provenance research of mosaics should be based on statistically representative tesserae samples, supplemented by microfacies studies of the building material used at the mosaic sites as well as investigation of nonlithic tesserae and the mortar bedding of the mosaics. The isotopic composition of limestone and dolomite tesserae also assists in the critical evaluation of microfacies categorization.     

Paleocene reefs on the Maiella Platform Margin, Italy: An example of the effects of the cretaceous/tertiary boundary events on reefs and carbonate platforms

Summary Reef facies, reef types and their biotic associations in the Maiella platform margin (central Italy) provide qualitative evidence for a significant reef decline across the Cretaceous/Tertiary (K/T) boundary, and indicate two phases of reef recovery during the Paleocene. Rudists dominated the reef community until the latest Cretaceous. A significant sea-level fall around the time of the K/T boundary is documented by a truncation surface associated with emersion. During sea-level highstands in the Danian to Early Thanetian and, more extensively, during the Late Thanetian, coral-algal patch-reefs grew along the platform margin and top. Already in the Danian to Early Thanetian, the reef communities were more diverse and the constructional types more evolved than previously known from this time. Differences between the Danian to Early Thanetian coral association, the Late Thanetian association, and Late Cretaceous coral faunas may have ecological or evolutionary causes. Repeated emergence produced a complex diagenetic history in the Danian to Lower Thanetian limestones. All Paleocene reefs were displaced by gravitative redeposition. Coral-algal reefs are less important in the Early to mid Eocene, when alveolinid foraminifera dominated on the Maiella shelf. Reefs on the Maiella platform diversified and attained large sizes in the Late Eocene to Early Oligocene, as known from other Mediterranean platforms. The external controls on the Late Cretaceous to Oligocene evolution and demise of reef communities that are most easily demonstrated with our data are sealevel fluctuations and climate change. We propose that the change in reef biota and reef types across the K/T boundary and during the Early Tertiary were important causes of the parallel changes in platform growth style.