Frasnian

Brachiopods (Productida [except Chonetidina], Orthida, Athyridida, Spiriferida [Adolfiidae, Reticulariidae, Ambocoeliidae, Thomasariidae], and Spiriferinida) recovered in the interval, in terms of the standard conodont zonation, between the Palmatolepis hassi and P. triangularis zones (Late Middle Frasnian to Early Famennian) in the Namur-Dinant Basin (Belgium) are described. The orders and suborders investigated include 32 species: 21 are described in open nomenclature, seven are previously known, four are new of which three are assigned to previously known genera: Aulacella aggeris n. sp., Dicamara plutonis n. sp., and Warrenella (Warrenella) aquaealbae n. sp. Th e fourth species belonging to a newly defined genus: Neptunathyris buxi n. gen., n. sp. A major brachiopod faunal change occurs at the top of the P. rhenana Zone in southern Belgium, with the disappearance of most existing species in parallel with the deterioration of the oxygenation conditions preceding the Upper Kelwasser Event. Only an impoverished fauna (Lingulida, Chonetidina, Rhynchonellida) has been collected in the P. linguiformis Zone. The recovery of the Famennian brachiopods after the end-Frasnian biotic crisis was rapid in the basal Famennian but, despite their great abundance, their diversity was relatively low. New cosmopolitan genera appeared at this time especially among the rhynchonellids, athyridids and spiriferids with new species of pre-existing orthid and orthotetid genera.

Becker, R. T. & Aboussalam, Z. S. & Stichling, S. & May, A., & Eichholt, S. (2016): The Givetian-Frasnian Hönne Valley Reef Complex (northern Sauerland) – an outline of stratigraphy and facies development. In: Becker, R. T., Hartenfels, S., Königshof, P., & Helling, S. (eds): Middle Devonian to Lower Carboniferous stratigraphy, facies, and bioevents in the Rhenish Massif, Germany - an IGCP 596 Guidebook. - Münstersche Forschungen zur Geologie und Paläontologie, vol. 108: p. 126-140, 20 figs.; Münster.

ABSTRACT: The northern margin of the 1st order Remscheid-Altena Anticline (northern Sauerland) is characterized between Hagen in the W and Balve in the ESE by an elongated, thick Givetian reef complex, the Hagen-Balve Reef, which can be divided into partial reefs. In the roughly N-S running Hönne Valley, between Oberrödinghausen and Eisborn (see huge Asbeck quarry), it reaches its maximum thickness of almost 1000 m.
This paper gives data on localities showing:
- initial reef stadium abruptly overlying the lower Givetian Upper Honsel Formation
- first coral biostrome (Hönne forest track)
- fossiliferous platform facies with Stringocephalus banks and intercalating tuff (Emil Quarry)
- overview of thick, cyclic main reef (Asbeck)
- first reef drowning in the course of the global Frasnes Events (Beul)
- final middle Frasnian reef extinction (Beul)

Late Frasnian Petit-Mont Member carbonate mounds occur in the southern part of the Dinant Synclinorium and in the Philippeville Anticline (SW Belgium). These mounds are 30 to 80 m thick and 100 to 250 m in diameter. They are embedded in shale, nodular shale and argillaceous limestone. Based on facies mapping of 14 buildups and related off-mound sediments, these mounds typically started from below the photic and storm wave base zones and builtup into shallow water environments. Above an argillaceous limestone substrate, the first carbonate mound facies consists of spiculitic wackestone with stromatactis (PM1), which becomes progressively enriched in crinoids and corals (PM2), then in peloids, stromatoporoids and cyanobacteria (PM3). PM4 consists of algal – coral – peloid wackestone and packstone with green algae and thick algal coatings. A core of algal and microbial bindstone (PM5) sporadically occurs within large mounds. The uppermost part of these mounds may show a recurrence of facies PM2 and PM1. PM1 to PM3 are coloured red by hematite derived from microaerophilic iron bacteria; PM4 and PM5 are grey. The transition from the aphotic to the cyanobacterial photic zone is recorded in the succession PM2 – PM3; the transition from the cyanobacterial to the green algal photic zone is recorded by PM3 – PM5. Storm wave base was reached within PM3 and fair-weather wave base within PM5. This paleobathymetric interpretation suggests a depth of 100 – 150 m during initial establishment of PM1. Three types of mounds can be distinguished on the basis of geometry and facies architecture: (1) ''Les Bulants''-type mounds display a continuous vertical facies succession (PM2 – 3 – 4 – 5) and low relief; (2) although exhibiting the same facies succession as ''Les Bulants'', ''Les Wayons''-type mounds show a distinct relief with steep flanks and bioclastic talus; (3) ''St.-Rémy'' mounds consist exclusively of PM1 and PM2, bioclastic flank deposits are not observed. From (1) to (3), these mound types represent successive deepening down a ramp. Biostratigraphic correlation on a regional scale provides good evidence that relative sea-level changes largely controlled lateral and vertical transitions of facies. Beyond that, hypoxic conditions are indicated by the sponge and iron-bacteria consortium in lower parts of the mounds. This is in agreement with the general assumption of stratified water masses during Late Frasnian, preceding the prominent Lower Kellwasser crisis. Cementation began with a radiaxial synsedimentary cement. A fringe of meteoric phreatic cement, initially nonluminescent, then with a bright orange luminescence, occurs in all mounds. It is contemporaneous with a nonluminescent pervasive cement of grainstones deposited in littoral areas. Differentiation between the (reducing) mounds and the (oxidizing) littoral area resulted from better aquifer circulation in sedimentary bodies close to the recharge area. Late burial cements occlude all the remaining porosity and are contemporaneous with the opening of the Variscan fracture system.

May, A. (2008): Corals (Anthozoa, Tabulata and Rugosa) and chaetetids (Porifera) from the Devonian of the Semara area (Morocco) at the Museo Geominero (Madrid, Spain), and their biogeographic significance. - Bulletin de l’Institut Scientifique, Rabat, section Sciences de la Terre, 30: 1-12, pl. 1-2; Rabat.

Abstract. The paper describes the three tabulate coral species Caliapora robusta (Pradáčová, 1938), Pachyfavosites tumulosus Janet, 1965 and Thamnopora major (Radugin, 1938), the rugose coral Phillipsastrea ex gr. irregularis (Webster & Fenton in Fenton & Fenton, 1924) and the chaetetid Rhaphidopora crinalis (Schlüter, 1880). The specimens are described for the first time from Givetian and probably Frasnian strata of Semara area (Morocco, former Spanish Sahara). The material is stored in the Museo Geominero in Madrid. The tabulate corals and the chaetetid demonstrate close biogeographic relationships to Central and Eastern Europe as well as to Western Siberia. Thefauna does not show any special influence of the Eastern Americas Realm. 

Key words: Anthozoa, biogeography, Devonian, tabulate corals, Morocco, West Sahara palaeogeographic province  Coraux (Anthozoa, Tabulata et Rugosa) et chaetétides (Porifera) du Dévonien de la région de Smara (Maroc) déposés au Museo  Geominero (Madrid) et leur signification biogéographique.  Résumé. L´article décrit trois espèces de coraux tabulés : Caliapora robusta (Pradáčová, 1938), Pachyfavosites tumulosus Janet, 1965, et Thamnopora major (Radugin, 1938), le corail rugueux Phillipsastrea ex gr. irregularis (Webster & Fenton in Fenton & Fenton, 1924)  ainsi que le chaetétide Rhaphidopora crinalis (Schlüter, 1880). Les spécimens, entreposés au Museo Geominero de Madrid, proviennent  des couches givétiennes et probablement frasniennes de différents gisements de la région de Smara (Maroc, ancien Sahara espagnol), d’où  elles sont décrites pour la première fois. Les coraux tabulés et le chaetétide prouvent l’existence de relations biogéographiques proches  entre l´Europe centrale et orientale mais aussi avec l’Ouest de la Sibérie. La faune ne présente pas de relations particulières avec celle du  Domaine Est-Américain. 

Mots clés: Anthozoa, biogéographie, Dévonien, coraux tabulés, Maroc, Province paléogéographique du Sahara Occidental

Brachiopods of the orders Strophomenida, Orthotetida, and Athyridida from the late middle Frasnian–early Famennian interval (hassi to triangularis conodont zones) in the Namur-Dinant Basin (southeastern margin of Laurussia; southern Belgium) are described. Nine genera and subgenera represented by 12 species are recognized here. One new genus, Retrorstrophia, and one new species, Douvillina area, are erected. Crinisarina stainbrooki is proposed to solve the homonymy between C. reticulata (Gosselet, 1877) and Cleiothyridina reticulata Stainbrook, 1947, the type species of Crinisarina Cooper and Dutro, 1982. A lectotype is selected and illustrated for C. reticulata. A new name is also proposed for Athyris reticulata Chen and Xu, 2000, which is assigned here to Crinisarina: C. shashishanensis nom. nov. In southern Belgium, the last representatives of the families Douvillinidae and Leptostrophiidae (Strophomenida) are from the Upper rhenana Zone (late Frasnian). Athyridid brachiopods, especially the representatives of the subfamily Cleiothyridininae constituted a significant part of the early Famennian recovery faunas with spiriferids and rhynchonellids, just after the late Frasnian mass extinction.

In the Namur–Dinant Basin (Belgium), the last Atrypida and Pentamerida originate from the top of the Upper Palmatolepis rhenana Zone (Late Frasnian). Within this biozone, their representatives belong to the genera Costatrypa, Desquamatia (Desquamatia), Radiatrypa, Spinatrypa (Spinatrypa), Spinatrypina (Spinatrypina?), Spinatrypina (Exatrypa), Waiotrypa, Iowatrypa and Metabolipa. No representative of these orders occurs within the Palmatolepis linguiformis Zone. The disappearance of the last pentamerids, mostly confined to reefal ecosystems, is clearly related to the end of the edification of the carbonate mounds; it precedes shortly the atrypid one. This event, resulting from a transgressive episode, which induces a progressive and dramatic deterioration of the oxygenation conditions, takes place firstly in the most distal zones of the Namur–Dinant Basin (southern border of the Dinant Synclinorium; Lower P. rhenana Zone). It is only recorded within the Upper P. rhenana Zone in the Philippeville Anticlinorium, the Vesdre area, and the northern flank of the Dinant Synclinorium. It would seem that the terebratulids were absent during the Famennian in this basin, probably due to inappropriate facies. Among the 13 species described or briefly discussed (Palmatolepis hassi to Upper P. rhenana zones), Pseudoatrypa godefroidi nov. sp. and Spinatrypina (Exatrypa) marmoris nov. sp. are proposed as new.

The Upper Frasnian sequence of the Namur–Dinant Basin in southern Belgium consists of mixed siliclastic–carbonate succession of a ramp setting, where the sequence spans the rhenana–linguiformis conodont zones. Earlier studies investigated the chemostratigraphic variations during the Frasnian-Famennian event, but little has been yet known about the nature of the counterpart variations that immediately preceded that time interval. Despite the scarcity of well-preserved brachiopods, sixty–one calcitic shells were collected mainly from beds of the Neuville and Les Valisettes formations (Lower and Upper rhenana zones), to investigate biochemostratigraphic profiles of oxygen-, carbon-isotope and rare earth element (REE) variations of the time interval immediately before the Frasnian-Famennian boundary. The δ18O and δ13 C values of the well-preserved shells range from − 9.5 to − 5.6 ‰ VPDB (− 7.7 ± 1.1, n = 33) and from − 1.8 to 3.8 ‰ VPDB (1.1 ± 1.7, n = 33), respectively, which are within the documented global values. The C- and O-isotope profiles exhibit parallel shifts, particularly at the top of the Neuville Formation (top of the Lower rhenana Zone), which are associated with a sea-level rise and shrinkage in the brachiopod community. Also, the Th/U (0.9 ± 0.6, n = 16) and Ce/Ce* (2.2 ± 0.5, n = 16) ratios suggest deposition under reducing conditions consistent with sea transgression.

The cause of the Frasnian-Famennian boundary (FFB) biotic crisis, one of the " Big Five " Phanerozoic mass extinctions, remains poorly understood. Here, we generated a high-resolution uranium-isotope profile (δ 238 U) for a marine carbonate section at Baisha, South China, in order to document secular variation in mean global-ocean redox conditions and to compare its relationship to coeval changes in organic carbon burial fluxes (as proxied by δ 13 C carb) and global climate conditions. δ 238 U varied in a coordinated, mostly positive relationship with δ 13 C carb , indicating that expanded (reduced) oceanic anoxia was linked to lower (higher) productivity. This pattern is inconsistent with productivity control of redox conditions and suggests instead that both proxies responded to a common climatic forcing. We infer that climatic cooling (and glaciation during the Upper Kellwasser Horizon [UKH] event) led to better-ventilated oceanic conditions (higher δ 238 U) and greater productivity (higher δ 13 C carb) owing to invigoration of global-ocean overturning circulation and enhanced upwelling. Because the UKH event coincided with the FFB mass extinction, cooling rather than oceanic anoxia may have been the main killing mechanism.

May, A. (1996a): Relationship among sea-level fluctuation, biogeography, and bioevents of the Devonian: an attempt to approach a powerful, but simple model for complex long-range control of biotic crises. - Geolines, 3: 38-49, 2 figs.; Praha.

ABSTRACT. Connections among changing sea-level, development of marine biogeography and appearance of bioevents in Devonian times are emphasised. Decreasing Devonian provincialism of the marine fauna reflects rising sea-level of global ocean. Whereas the Emsian sea-level lowstand was accompanied by strong provincialism of the marine communities, the Frasnian highstands were linked to an unusual decrease of provincialism. As generally documented, the partial but intensive transgressional events (often related to bioevents) were usually associated with a decrease of the provincialism. The best explanation for the majority of Devonian bioevents is the effect of oceanic anoxia. A model suggested herein operates with a fast transgression related to fast ocean sea-level rise. A direct consequence of this fast transgression was the increased primary biomass production (caused by both increased infiux of nutrients and increased total surface of shallow seas). Decreased oxygen supply of oceans continued this process being caused by the global temperature increase which resulted from the albedo decrease. These consequences of these combined factors produced an oceanic anoxic event which started the extinction processes of the bioevent. The well-documented pattern of intensified biological crises during the Devonian, time-slice by time-slice (from Emsian to Frasnian), is explained as a direct result of decreased provincialism of the marine fauna. Both decrease of the provincialism and increased intensity of the Devonian bioevents can be deduced directly or indirectly from changes of global sea-level. This simply constructed but very complex explanation yields two advantages: first, it needs only very few infiuencing factors, second, it can basically renounce incalculable influences (e.g. meteorite impacts). The suggested concept of oceanic anoxic events can explain also other major bioevents of the Earth history.

KURZFASSUNG: Der Artikel versucht, Zusammenhänge zwischen den Veränderungen des Meeresspiegels, der Entwicklung der marinen Biogeographie und den Bioevents im Devon herauszuarbeiten und zu erklären. Die Entwicklung des Faunen-Provinzialismus im Devon ist ein Ergebnis der Entwicklung des globalen Meeresspiegels. Im Emsium war der Meeresspiegel niedrig und der Provinzialismus der Meeresfauna gross, im Frasnium war der Meeresspiegel hoch und der Provinzialismus sehr gering. Insbesondere einige Trangressions-Schübe, die sich auch als Bioevents bemerkbar machten, führten zu schnellen Abnahmen der Grösse des Provinzialismus. Die beste Erklärung für die meisten devonischen Bioevents ist das Auftreten von ozeanischen anoxischen Events. Das hier vorgestellte Modell setzt bei schnellen Transgressionen an, die durch schnelle Meeresspiegel-Anstiege verursacht wurden. Die Konsequenzen einer schnellen Transgression waren gesteigerte Primär produktion organischer Substanz und geringere Sauerstoff- Versorgung der Ozeane, was zusammen zum ozeanischen anoxischen Event und zum Bioevent führte. Der Umstand, dass die Intensität der Bioevents vom Emsium zum Frasnium zunahm, wird durch die Abnahme des Provinzialismus der Meeresfauna in dieser Zeit erklärt. Sowohl die Entwicklung des Provinzialismus der marinen Fauna als auch das Auftreten und die Intensität der Bioevents im Devon lassen sich direkt oder mittelbar aus der Entwicklung des globalen Meeresspiegels ableiten. Dieser sehr umfassende Erklärungsansatz hat den Vorteil, mit sehr wenigen Einfiussfaktoren auszukommen und auf unkalkulierbare Einwirkungen (wie z.B. Meteoriten-Einschläge) völlig verzichten zu können. Vermutlich ist das hier entwickelte Konzept eines ozeanischen anoxischen Events auch auf andere Bioevents übertragbar.

KEYWORDS: Devonian, Kellwasser Event, ecosystems, biogeography, sea level fiuctuation.

May, A. (1997a): Verwitterungsbeständigkeit und Verwitterung von Naturbausteinen aus Kalkstein. - Geologie und Paläontologie in Westfalen, vol. 48: p. 3-185, 94 figs., 2 tabs., pl. 1-11; Münster.

Abstract: Weathering durability and weathering process of natural building stones from the Lower Muschelkalk, the Upper Muschelkalk, and the Devonian have been investigated. Various properties of each building stone and its limestone material are measured (microscopy, SEM, porosity, ultrasonic velocity, geochemical methods). Defined microfacies types show clear differences in their weathering durability. The quantities of the cold water absorption, the Schurecht ratio (= ratio cold/boiling water absorption), and the residue insoluble by hydrocloric acid strongly affect the weathering durability. Together with the investigation of thin-sections, these properties enable prognoses about the weathering durability. A diagram of correlation between coldwater absorption and Schurecht ratio is developed, which is able to discriminate more durable and less durable limestones by a boundary line (Fig. 59-60).The limestones are mainly damaged by fissures which harm the unity of the stone. Probably these fissures are mainly based on frost phenomena. Connections between the sedimentary environment and the weathering durability are recognizable: generally limestones of the agitated (shallow) marine are more durable than other limestones.

Kurzfassung: Es wurden die Unterschiede in der Verwitterungsbeständigkeit zwischen verschiedenen Varietäten jeweils eines Kalksteins untersucht. Beprobt wurden Kalksteine des Muschelkalks im Raum Osnabrück-Bielefeld und des Devons im Sauerland in Bauwerken und Aufschlüssen. Eine neue Klassifikation des Verwitterungszustandes von Kalkstein-Mauersteinen wurde entwickelt. Die Oberflächenschäden auf der Außenseite sind nur ± gering und stellen bloß ein "kosmetisches" Problem dar. Die Stärke der Schädigung des inneren Zusammenhaltes des Mauersteins durch Risse ist viel wichtiger, da sie die Sicherheit und Stabilität des Bauwerks gefährdet. Die Untersuchung von Dünnschliffen ermöglichte es, insgesamt 17 Mikrofaziestypen zu definieren und erstmalig Unterschiede in der Verwitterungsbeständigkeit zwischen den verschiedenen Mikrofaziestypen eines Kalksteins zu erkennen. Kalksteine, die in ± turbulentem (und damit ± flachem) Meereswasser abgelagert wurden, sind tendenziell verwitterungsbeständiger als solche aus anderen Ablagerungsräumen. Mit der Auftriebsmethode wurden wichtige Porositätsparameter festgestellt. Freiwillige Wasseraufnahme und Schurecht-Ratio (= Quotient freiwillige Wasseraufnahme / effektive Porosität) beeinflussen die Verwitterungsbeständigkeit sehr stark, wenn ihre Größe zunimmt, nimmt die Verwitterungsbeständigkeit ab. Die Ultraschall-Untersuchungen zeigten, daß in Kalksteinen Spannungen viel weiter geleitet werden als in Sandsteinen und deshalb zu (lang aushaltenden) Rissen führen. Die rasterelektronenmikroskopische Untersuchung erlaubte Aussagen über einzelne Aspekte des Verwitterungsprozesses. Die im salzsäurelöslichen Gesteinsanteil gemessenen Element-Konzentrationen spielen keine Rolle für die Verwitterungsbeständigkeit der Kalksteine.  Die Verwitterungsbeständigkeit der bearbeiteten Kalksteine wird am stärksten von freiwilliger Wasseraufnahme und Schurecht-Ratio beeinflußt. Der Einfluß des Gehaltes an salzsäureunlöslichem Rückstand ist erheblich geringer. Darüber hinaus spielen auch die Merkmale Feinschichtung und Kristallgröße (Mikritl Sparit) eine gewisse Rolle. Die Entwicklung von Stylolithen hat nur nachrangige Bedeutung. Einen sehr großen praktischen Nutzen für Prognosen über die Verwitterungsbeständigkeit verspricht die erstmalig ermittelte Grenzlinie Schurecht-Ratio/freiwillige Wasseraufnahme, die unabhängig vom Probenkollektiv überdurchschnittlich und unterdurchschnittlich verwitterungsbeständige Kalkstein-Mauersteine mit ziemlich großer Schärfe voneinander trennt. Darauf aufbauend wurden leicht durchzuführende Verfahren zur Auswahl besonders verwitterungsbeständiger Kalksteine entwickelt. Im Gegensatz zur vorherrschenden Literaturmeinung werden Kalksteine im wesentlichen durch Risse geschädigt, die wahrscheinlich aufgrund von Frosterscheinungen (bzw. Frost-Tau-Wechsel-Prozessen) entstehen und hauptsächlich durch Frostsprengung vergrößert werden. Da die Schädigung der Gesteinsoberfläche ± gering ist, kann die chemische Verwitterung für Kalksteine nicht wichtig sein. Hierdurch unterscheiden sich Kalksteine in ihrem Verwitterungsverhalten sehr stark von Kalksandsteinen.

Preliminary review of taxonomy of the brachiopod order AĘpida and its stratigraphic distribution in the late Frasnian Kellwasser Crisis of several regions of Laurussia, westem Siberia and South China point to their moderate diversity and stepdown but irregular extinction pattern. The distinctive character of the late Frasnian atrypid fauna is emphasised by several relict genera, marked by recurrent and possibly aberrant characters (mainly in ornamentation types), tendency to size reduction and homeomorphy in some taxa. The transgressive/hypoxic Lower Kellwasser Event and preceding eustatic changes during the Palmatolepis rhenanaZone had only a regional destructive effect, and were linked rather to an enhanced dispersal of the last generic set of aĘpids. The VariaĘpinae, Spinatrypinae and Iowatryp,a-group seem to belong to the latest surviving atrypids. The final demise of the remaining atrypids (and some other articulate brachiopods, e.g., gypidulids) coincided with the fransgressiv...

May, A. (1994a): Microfacies controls on weathering of carbonate building stones: Devonian (northern Sauerland, Germany). - Facies, 30: 193-208, 1 figs., 2 tabs., pl. 37-39; Erlangen.

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.

The facies architecture, sedimentary dynamics and palaeogeographic evolution were reconstructed for a number of middle-late Frasnian carbonate mounds from the south side of the Dinant Synclinorium (Belgium). Nine facies were recognized in the buildups, each characterized by a specific range of textures and assemblage of organisms: spiculitic wackestone with stromatactis (facies Pm1), which becomes progressively enriched in crinoids and corals (Pm2); grey or pinkish limestone with stromatactis, corals and stromatoporoids (A3–L3, Pm3); grey limestone with corals, peloids and dasycladales (A4–L4, Pm4); grey, microbial limestone (A5–L5, Pm5); grey limestone with dendroid stromatoporoids (A6–L6); grey, laminar fenestral limestone, (A7–L7); and grey, bioturbated limestone (A8–L8). Sedimentological evidence suggests that facies Pm1 and Pm2 correspond to iron bacteria-sponge-dominated communities, developing in a quiet aphotic and hypoxic environment. A3–L3 developed between storm and fair-...

May, A. (1994i): Foraminiferen, Kalkalgen und andere Mikrofossilien aus dem Givetium und Frasnium (Devon) des Sauerlandes (Rheinisches Schiefergebirge). - Dortmunder Beiträge zur Landeskunde, Naturwissenschaftliche Mitteilungen, 28: 7-31, 19 figs., 2 tabs.; Dortmund.

Abstract: The Beisinghausen Limestone (Upper Givetian to Frasnian) from Eslohe-Reiste in the eastern Sauerland (Rhenish Massif) consists of proximal turbidites. The particles came from the Middle to Upper Devonian Massenkalk reef complex of Attendorn and Elspe and they can be attached to different parts of the reef complex. The Beisinghausen Limestone shows a remarkable rich content of microfossils, consisting of foraminifera, calcisphaeres, calcareous algae, and microproblematica. These microfossils are described. The content of microfossils of the Beisinghausen Limestone is compared with the content of microfossils of two Lower Givetian coral-limestone horizons from the northwestern Sauerland as weil as the content of microfossils of the Upper Givetian lagoonal Massenkalk from the Brilon reef complex in the eastern Sauerland (table 1-2).

Kurzfassung: Der Beisinghäuser Kalk (Ober-Givetium bis Frasnium) von Eslohe-Reiste im östlichen Sauerland besteht aus proximalen Turbiditen. Die Partikel stammen aus dem mittel- bis oberdevonischen Massenkalk-Riffkomplex von Attendorn und Elspe und lassen sich verschiedenen Bereichen des Riffkomplexes zuordnen. Der Beisinghäuser Kalk zeigt eine auffällig reiche Mikrofossilführung aus Foraminiferen, Calcisphaeren, Kalkalgen und Mikroproblematika. Die Mikrofossilführung des Beisinghäuser Kalkes wird beschrieben und sowohl mit der Mikrofossilführung von zwei Korallenkalk-Horizonten aus dem Unter- Givetium des nordwestlichen Sauerlandes als auch mit der Mikrofossilführung des obergivetischen lagunären Massenkalkes im Briloner Riffkomplex (Ost-Sauerland) verglichen (Tabelle 1-2).

at least 8.5 m in diameter and 0.85 m in height, occurs in the Œluchowice quarry in Kielce, Holy Cross Mountains. This sponge occurs in growth position within Early Frasnian (transitans Zone) intraclast-rich reef-rubble deposits. A unique preservation of the reef-builder close to a reef core is implied for the northern flank of the developing Dyminy Reef during its maximum expansion northward into the Kostomoty intrashelf basin.

The Bitlis-Pötürge Massif of SE Turkey is a metamorphic belt separating the Arabian Plate from the Taurides. It includes a non-metamorphic Palaeozoic sequence that contains locally fossiliferous strata. Here is reported for the first time an assemblage of Upper Devonian rugose and tabulate corals from the Meydan Formation, composed of the rugose Frechastraea schafferi (penecke), Peneckiella cf. teicherti Hill, Pseudopexiphyllum supradevonicum (penecke), and Macgeea desioi von schouppé, and the tabulate Thamnopora reticulata (de blainville), Alveolites ex. gr. suborbicularis and Scoliopora sp. The rugose corals suggest a Late Frasnian age. The palaeobiogeographic affinities of corals are discussed. The species F. schafferi and the genus Pseudopexiphyllum –so far only reported from Turkey, Iran and Afghanistan– are probably limited to the northern margin of Gondwana and therefore diagnostic for this palaeogeographic area. Until now, the northern margin of Gondwana yielded very few Upper Devonian corals so this occurrence in SE Turkey is particularly important to estimate the relationship between these corals and the ones from the northern margin of the Palaeotethys Ocean.

Preliminary review of taxonomy of the brachiopod order AĘpida and its stratigraphic distribution in the late Frasnian Kellwasser Crisis of several regions of Laurussia, westem Siberia and South China point to their moderate diversity and stepdown but irregular extinction pattern. The distinctive character of the late Frasnian atrypid fauna is empha-sised by several relict genera, marked by recurrent and possibly aberrant characters (mainly in ornamentation types), tendency to size reduction and homeomorphy in some taxa. The transgressive/hypoxic Lower Kellwasser Event and preceding eustatic changes during the Palmatolepis rhenanaZone had only a regional destructive effect, and were linked rathęr to an enhanced dispersal of the last generic set of aĘpids. The VariaĘpi-nae, Spinatrypinae and Iowatryp,a-group seem to belong to the latest surviving atrypids. The final demise of the remaining atrypids (and some other articulate brachiopods, e.g., gypidulids) coincided with the fransgress...

May, A. (1995c): Thamnopora (Anthozoa: Tabulata) aus dem Givetium bis Frasnium von Asturien (Devon, Nord-Spanien). - Münstersche Forschungen zur Geologie und Paläontologie, 77: 479-491, pl. 2; Münster.

Abstract: Three species of ramose tabulate corals of the genus Thamnopora are described in detail. The material originates from the Candas Formation (Givetian to Frasnian) and the Pinieres Formation (Frasnian) of the central Asturian coast as weil as from the Portilla Formation (Givetian) of Asturias. Thamnopora nicholsoni (FRECH 1885) and Thamnopora bilamellosa ERMAKOVA 1960 are found in Spain for the first time. These corals have only a little biostratigraphical importance. They indicate close paleobiogeographical relations to Siberia.

Kurzfassung:  Aus der Candas-Formation (Givetium bis Frasnium) und der Pinieres-Formation (Frasnium) der mittelasturischen Küste sowie der Portilla-Formation (Givetium) Asturiens werden 3 Arten ästiger tabulater Korallen der Gattung Thamnopora ausführlich beschrieben. Thamnopora nicholsoni (FRECH 1885) und Thamnopora bilamellosa ERMAKOVA 1960 werden erstmalig in Spanien nachgewiesen. Diese Korallen besitzen nur eine geringe biostratigraphische Bedeutung. Sie zeigen enge paläobiogeographische Beziehungen zu Sibirien.

The cause of the Frasnian-Famennian boundary (FFB) biotic crisis, one of the " Big Five " Phanerozoic mass extinctions, remains poorly understood. Here, we generated a high-resolution uranium-isotope profile (δ 238 U) for a marine carbonate section at Baisha, South China, in order to document secular variation in mean global-ocean redox conditions and to compare its relationship to coeval changes in organic carbon burial fluxes (as proxied by δ 13 C carb) and global climate conditions. δ 238 U varied in a coordinated, mostly positive relationship with δ 13 C carb , indicating that expanded (reduced) oceanic anoxia was linked to lower (higher) productivity. This pattern is inconsistent with productivity control of redox conditions and suggests instead that both proxies responded to a common climatic forcing. We infer that climatic cooling (and glaciation during the Upper Kellwasser Horizon [UKH] event) led to better-ventilated oceanic conditions (higher δ 238 U) and greater productivity (higher δ 13 C carb) owing to invigoration of global-ocean overturning circulation and enhanced upwelling. Because the UKH event coincided with the FFB mass extinction, cooling rather than oceanic anoxia may have been the main killing mechanism.

May, A. (1997f): Sind die devonischen Riffe des Sauerlandes heutigen Korallenriffen vergleichbar?. - Dortmunder Beiträge zur Landeskunde, Naturwissenschaftliche Mitteilungen, 31: 127-135, 2 figs.; Dortmund.

Abstract: In this paper reasons are given, why the Massenkalk reefs (Middle to Upper Devonian) of the Sauerland are not comparable to recent coral reefs. A new model is developed, explaining the observed carbonate facies without contradiction. This model assumes, that the "reef cores" of the Massenkalk reefs were no barrier, but the uppermost part of the basinward directed slope of the carbonate platform.

Kurzfassung: In diesem Artikel wird begründet, warum die Massenkalk-Riffe (Mittel- bis Oberdevon) des Sauerlandes nicht vergleichbar mit rezenten Korallenriffen sind. Daraus wird ein neues Modell entwickelt, das die beobachteten Karbonatfazies widerspruchsfrei erklären kann. Dieses Modell geht davon aus, daß der "Riffkern" des Massenkalk-Riffs keine Barriere darstellte, sondern den obersten Teil des beckenwärts gerichteten Abhanges der Karbonatplattform.

May, A. (1994c): Paleoecology and paleobiogeography of corals and other reef-builders from the Middle Devonian of the Sauerland (Germany). - In: Proceedings of the VI. International Symposium on Fossil Cnidaria and Porifera held in Münster, Germany 9.-14. September 1991, Volume 2,Courier Forschungsinstitut Senckenberg, 172: 147-159, 6 figs., 1 tabs.; Frankfurt am Main.

Abstract: In the NW Sauerland the coral limestone horizons of the uppermost Eifelian and the Lower Givetian show a very rich content of fossils: 28 tabulate coral species, 21 rugose coral species, 21 stromatoporoid species, 2 chaetetid species, and 16 calcareous algae species were identified by the author. They generally lived in a warm, normal marine environment in the shallow euphotic zone. An analysis of the lagoonal Massenkalk sediments (upper Lower Givetian to Frasnian) shows intertidal to subtidal cyclic sedimentation. Herein several reef-builder associations can be recognized. Their composition and distribution depend on water depth as weil as on the restriction of their environment. The Upper Eifelian and Lower Givetian reef-builder fauna of the Saueriand corresponds to the fauna of the Eifel Hills and the Ardennes, but a few of the Saueriand species are up to now only known from occurrences east of it. The "Rhenohercynian Basin" was a marginal sea, into which faunas from the Asiatic part of the "Old Worid Realrn" immigrated. A marine connection to the "Eastem Americas Realrn" was opened in the Upper Givetian.

May, A. (1997g): Ein Modell zur Erklärung der Bio-Events und der biogeographischen Entwicklung im Devon durch den Meeresspiegel. - Dortmunder Beiträge zur Landeskunde, Naturwissenschaftliche Mitteilungen, 31: 137-174, 5 figs.; Dortmund.

Abstract: The attempt is made, to show and to explain connections between the changing sea-Ievel, marine biogeography, and bio-events within the Devonian. The Devonian development of marine faunal provincialism is the result of changes in global sea-Ievel. Within the Emsian sea-Ievel was low and marine faunal provincialism was strong, while within the Frasnian sea-Ievel was high and marine faunal provincialism was weak. Some particular transgressive intervals made themselves felt as bio-events, conducive to fast decreases in the intensity of provincialism. Starting with the Daleje Event of the Emsian and ending with the Kellwasser Event of the Frasnian, the bio-events are discussed in detail. In this context new data concerning the Middle Devonian of the Eastern Rhenish Massif are presented. The best explanation for most Devonian bio-events is the occurrence of oceanic anoxic events. The model presented here uses fast transgressions caused by rapid sea-Ievel rises (see fig. 1). Fast transgression increased primary biomass production (caused by an increased influx of nutrients and an increased area of shallow sea) and decreased oxygen supply in the oceans (caused by global temperature increase resulting from albedo decrease). Both factors together resulted in the oceanic anoxic event conducive to the bio-event. The fact, that bio-event intensity increased from the Emsian to the Frasnian is explained by the decrease of marine faunal provincialism within this time. Both the development of provincialism and the occurrence and intensity of bio-events within the Devonian can be deduced directly or indirectly from the changes in global sea-Ievel. This comprehensive attempt at explanation has the advantage of needing only a few influencing factors and renouncing incalculable influences (e. g. meteorite impacts). Possibly, the model of oceanic anoxic events presented is also transferable to other bio-events (e. g.: bio-events of the Famennian, Cenomanian/Turonian Event). Kurzfassung: Der Artikel versucht, Zusammenhänge zwischen den Veränderungen des Meeresspiegels, der Entwicklung der marinen Biogeographie und den Bio-Events im Devon herauszuarbeiten und zu erklären. Die Entwicklung des Faunen-Provinzialismus im Devon ist ein Ergebnis der Entwicklung des globalen Meeresspiegels. Im Emsium war der Meeresspiegel niedrig und der Provinzialismus der Meeresfauna groß, im Frasnium war der Meeresspiegel hoch und der Provinzialismus sehr gering. Insbesondere einige Trangressions-Schübe, die sich auch als Bio-Events bemerkbar machten, führten zu schnellen Abnahmen der Größe des Provinzialismus. Die Bio-Events vom Daleje-Event des Emsiums bis zum Kellwasser-Event des Frasniums werden detailliert besprochen. In diesem Zusammenhang werden auch neue Daten zum Mitteldevon des Rechtsrheinischen Schiefergebirges gegeben. Die beste Erklärung für die meisten devonischen Bio-Events ist das Auftreten von ozeanischen anoxischen Events. Das hier vorgestellte Modell setzt bei schnellen Transgressionen an, die durch schnelle Meeresspiegel-Anstiege verursacht wurden (siehe Abb. 1). Die Konsequenzen einer schnellen Transgression waren gesteigerte Primärproduktion organischer Substanz und geringere Sauerstoff-Versorgung der Ozeane, was zusammen zum ozeanischen anoxischen Event und zum Bio-Event führte. Der Umstand, daß die Intensität der Bio-Events vom Emsium zum Frasnium zunahm, wird durch die Abnahme des Provinzialismus der Meeresfauna in dieser Zeit erklärt. Sowohl die Entwicklung des Provinzialismus der marinen Fauna als auch das Auftreten und die Intensität der Bio-Events im Devon lassen sich direkt oder mittelbar aus der Entwicklung des globalen Meeresspiegels ableiten. Dieser sehr umfassende Erklärungsansatz hat den Vorteil, mit sehr wenigen Einflußfaktoren auszukommen und auf unkalkulierbare Einwirkungen (wie z. B. Meteoriten-Einschläge) völlig verzichten zu können. Vermutlich ist das hier entwickelte Konzept eines ozeanischen anoxischen Events auch auf andere Bio-Events übertragbar.