Improving the parameterization of stromatoporoid shapes – a detailed approach to stromatoporoid morphometry

Eight specimens of Devonian stromatoporoids with well visible latilaminae arrangement exposed on polished slabs were subjected to a detailed morphometric analysis. The studies have revealed that the so far used stromatoporoid parameterization method leaves a broad field of uncertainty concerning the exact definitions of particular parameters. The possible ways of making the measurements and the propositions of more precise definitions of the parameters used in the method, both of the growth form above the sea bottom and of the whole skeleton are therefore presented in this paper. The B_m - basal length of the skeleton, has been defined as a straight line joining the two ends of the basal surface, which have been pointed basing on the stromatoporoid's overall shape, latilaminae arrangement and angular relation to the main growth axis position in ontogenetical development, length. The B_n - basal length of the growth form above the sea bottom, is to be measured along a straight line joining the ends of the last visible latilamina. From among a number of possible definitions of the V_m - vertical height of the whole skeleton, a straight line joining the initial growth nucleus and the highest point on the specimen's surface above the B_m line has been selected. The V_n - vertical height of the growth form above the sea bottom is defined as the height of the point on the stromatoporoid surface highest above the B_n measured perpendicularly to it. A parameter of burial ratio, BR=(V_m-V_n)/V_m, is introduced.     

Sedimentary history of Upper Silurian biostromes of Podolia (Ukraine) based on stromatoporoid morphometry

The sedimentary history of stromatoporoid biostromal accumulations reflecting various depositional conditions (autoparabiostromes and parabiostromes) is studied in two isochronous, Late Silurian carbonate sections of the Malynivtsy Formation from Podolia (western Ukraine, Kam'janec' Podil'skyj area). This study focuses on morphometrical analysis of massive stromatoporoids. Various stromatoporoid attributes, such as growth form, volume, surface character etc., are interpreted in terms of growth environments. Attributes of redeposited specimens are also analysed in terms of their susceptibility to exhumation and redeposition, and new criteria are presented in this matter. The exposed facies succession, which can be subdivided into three units: an oncolitic–fenestral complex and the stromatoporoid–coral complexes that underlie and cover it, represents the belt of shoals located at a considerable distance from shore, and its transition to a narrow zone of back-shoal tidal flats. The facies patterns proved to be strongly obscured by an intensive process of onshore redeposition of material during high energy episodes. These events caused exhumation and landward transport of stromatoporoids inhabiting soft-sediment bottoms of outer shelf areas, which were afterwards accumulated in parabiostromes in calm waters on lee side of a zone of shoals. The main process governing the distribution of redeposited stromatoporoids is fractional (weight) segregation. The high energetic events had less effect on stromatoporoid–coral autoparabiostromes that formed the zone of shoals, which were inhabited by stromatoporoids better adapted to permanent wave action, but nonetheless, they caused their partial reworking and depletion from those forms that did not resist redeposition, on one hand, and supplementation by specimens derived from offshore areas, on the other.     

Parameterization of stromatoporoid shape

Kershaw, Stephen & Riding, Robert 1978 07 15: Parameterization of stromatoporoid shape. Lethaia , Vol. 11. pp. 233–242. Oslo. ISSN 0024–1164.
Stromatoporoid cross-sectional shape can be considered as a product of the interaction of three morphological variables: the relative proportions of basal, vertical and diagonal dimensions. The gross arrangement of internal lamination can be superimposed upon the resulting outlines. These shapes are taken to represent cross sections in any vertical plane through the centre of the coenosteum. This simple parameterization scheme is presented in triangular arrays which include the stromatoporoid morphotypes laminar, domical and bulbous, and varieties of them together with forms not utilized by stromatoporoids. Dendroid and irregular forms are too complex to be readily included in the scheme. Smooth and ragged varieties of laminar and domical forms are distinguished and related to sedimentation on the flanks of the coenosteum. Two types of mutual arrangement of latilaminae within the coenosteum are recognized: enveloping, where they completely overlap previous latilaminae, and non-enveloping, where they do not. Laminar-domical-bulbous forms represent a series generated mainly by reduction of the basal dimension. They commonly exhibit enveloping latilaminae except in ragged varieties and some extended domes. Measurement of defined dimensions in the field allows stromatoporoid morphotypes to be plotted onto the triangular arrays and provides a rapid method of displaying the range of forms present.     

The relationship of the stromatoporoids to the sclerosponges

Similarities of the extinct strornatoporoids to the sponges of the recently established order Sclerospongia have strengthened arguments that these fossils are closer to the Porifera than to the Coelenterata. Major features favouring the affinity of the stromatoporoids to the sclerosponges include: (1) lack of evidence of colonialism in the strornatoporoids, (2) similarity of gross structure of some stromatoporoids to that of one sclerosponge ( Astrosclera ), (3) fibrous microstruc-ture of sclerosponges, Mesozoic stromatoporoids, and some Paleozoic stromatoporoids, (4) similarity of stromatoporoid astrorhizae to the excurrent canals of sclerosponges. Points of dissimilarity include: (1) the solid aragonitic skeletons of most sclerosponges, (2) the presence of dissepiments, laminae, and latilaminae in stromatoporoids, (3) the absence of siliceous spicules in stromatoporoids.
These comparisons suggest that the stromatoporoids were basically encrusting filter feeders like the sclerosponges but had progressed by loss of spicules and periodic introduction of dissepirnents and laminae toward a secretion of a skeleton of the coelenterate type. They cannot be placed with confidence in either the sclerosponges or the hydrozoans and should be recognized us a separate subphylum of the Porifera.     

Significance of stromatoporoids in Jurassic reefs and carbonate platforms—concepts and implications

Although many case studies describe stromatoporoid-rich Jurassic reefs, there are only few reliable data as to their distribution pattern. This is in part due to a largely taxonomic and systematic focus on the enigmatic stromatoporoids which now are interpreted as a polyphyletic informal group of demosponges by most specialists. The common co-occurrence of Jurassic scleractinian corals and stromatoporoids might, at first hand, point to very similar environmental demands of both organismic groups, but autecological considerations as well as evaluation of stromatoporoid distribution patterns should allow for a much more refined interpretation. This study concludes that Jurassic corals and stromatoporoids show a relatively broad overlap of environmental demands but their maximum ecological tolerances appear to differ considerably. Jurassic corals were dominating in mesotrophic to mildly oligotrophic, slightly deeper settings, where they largely outcompeted stromatoporoids. On the other hand, stromatoporoid growth was particularly favoured in very shallow water, strongly abrasive, high-energy settings as well as in possibly overheated waters. Many taxa and growth forms were very tolerant towards frequent reworking and redistribution, a feature which is compatible with the sponge nature of the stromatoporoids. As such, stromatoporoid facies may be common in low-accommodation regimes, giving rise to frequent “shelf shaving” and redistribution across wide shelf areas. The mixed coral-stromatoporoid reefs from the margins of isolated Intra-Tethys platforms are interpreted to be indicative of oligotrophic normal marine waters. This is corroborated by statistical cluster analysis of stromatoporoid taxa from representative areas. In addition, Arabian stromatoporoid occurrences might have been adapted to overheated and slightly hypersaline waters. There also are a few exceptional stromatoporoid taxa which might have had environmental tolerances different from the bulk tolerances of other Jurassic stromatoporoids. Part of our interpretations are preliminary and should stimulate further research. However, the present results already help explain the observed compositional differences between Jurassic North Tethys/North Atlantic, Intra-Tethys, and South Tethys shallow-water reefs and platforms.     

Indigenous demosponge spicules in a Late Devonian stromatoporoid basal skeleton from the Frasnian of Belgium

This paper records the first example of a demosponge spicule framework in a single specimen of a Devonian stromatoporoid from the Frasnian of southern Belgium. The small sample (2.5 × 2 cm) is a component in a brecciated carbonate from a carbonate mound in La Boverie Quarry 30 km east of Dinant. Because of the small size of the sample, generic identification is not confirmed, but the stromatoporoid basal skeleton is similar to the genus Stromatopora. The spicules are arranged in the calcified skeleton, but not in the gallery space, and are recrystallized as multi‐crystalline calcite. The spicules fall into two size ranges: 10–20 μm diameter and 500–2000 μm long for the large ones and between 5–15 μm diameter and 50–100 μm length for the small ones. In tangential section, the spicules are circular, they have a simple structure, and no axial canal has been preserved. The large spicules are always monaxons, straight or slightly curved styles or strongyles. The spicules most closely resemble halichondrid/axinellid demosponge spicules and are important rare evidence of the existence of spicules in Palaeozoic stromatoporoids, reinforcing the interpretation that stromatoporoids were sponges. The basal skeleton may have had an aragonitic spherulitic mineralogy. Furthermore, the spicules indicate that this stromatoporoid sample is a demosponge.     

An association between the stromatoporoid Diplostroma yavorskyi Nestor and calcareous algae from the Much Wenlock Limestone, England

Intergrowths of the stromatoporoid Diplostroma yavorskyi Nestor with calcareous algae are described for the first time from the Much Wenlock Limestone of Wenlock Edge, England. The intergrowth developed as irregular. nodular growth-forms which initiated around a nucleus of biomicrite sediment or skeletal clasts. The paired stromatoporoid laminae characteristic of this species form regular alternations throughout substantial portions of the skeleton with the calcareous algae Girvanella sp., Rothpletzella sp., Wetheredella sp. and Rhabdoporella sp., and micrite. Nodular growths developed as a result of intermittent rolling on the sea floor. The nature of the periodic intergrowth of different taxa suggests that the stromatoporoid grew on firm substrates by lateral growth at an edge zone. Epiphytes encrusted areas of the stromatoporoid skeleton devoid of soft tissue. □ Stromatoporoid. calcareous algae. epiphyte. intergrowth. Wenlock.     

Cavities and cryptic faunas beneath non-reef stromatoporoids

Kershaw, Stephen 1980 10 15: Cavities and cryptic faunas beneath non-reef stromatoporoids. Lethaia , Vol. 13 , pp. 327–338. Oslo. ISSN 0024–1161.
Stromatoporoids from level-bottom shales and argillaceous limestones in the Silurian of Gotland, Sweden, form substrates for a variety of encrusting and boring organisms. Overturned stromatoporoids have encrusters and borers on both upper and lower surfaces, while coenostea preserved in situ have encrusters on both surfaces but borings on upper surfaces only. This suggests that cavities, now infilled, existed below coenostea. The stromatoporoids are isolated and not part of a reef framework where growth alone could have created overhangs and cavities. The scouring activity of currents removing sediment from around and beneath the edges of coenostea, and small current-controlled movements leaving stromatoporoids imperfectly settled on the uneven substrate or partly overlying skeletal debris, are invoked to explain the presence of cavities and hence encrusters on stromatoporoid lower surfaces. Both processes probably operated on many specimens. The lower surfaces of these stromatoporoids also show basal concavities which range from shallow to deep and reflect the topography of the substrate and the success of stromatoporoids growing on positive features from which they could shed sediment easily. Overturned stromatoporoids and coenostea with deep, encrusted, basal concavities, point to violent environmental events, such as storms, more powerful than currents producing scour and small movements of coenostea.     

Cylindrical shapes of closed lipid bilayer structures correspond to an extreme area difference between the two monolayers of the bilayer

The shapes of extreme area difference between the outer and the inner layer (ΔA) of the closed lipid bilayer structures at fixed membrane area (A) and fixed volume (V) are determined by stating and analytically solving a variational problem for axisymmetric shapes. It is shown that the spheres with at most two different radii and the cylinder are the solutions of this variational problem. The cylinder ended by a hemisphere on each end is the shape combined from these solutions and is therefore, itself the shape of the extreme ΔA at fixed V and A. The related cylindrical shapes of stearoyl–oleoyl–phosphocholine vesicles are shown.     

High-energy sedimentary events in lagoonal successions of the Upper Silurian of Podolia, Ukraine

Three Late Silurian carbonate profiles of the Malynivtsy and Skala Formations from Podolia (western Ukraine) are discussed in terms of sedimentation dynamics. Their common feature is the appearance of thick, stromatoporoid-rich beds within fine-grained peritidal deposits. These intercalations are composed of fossils typical of offshore sedimentary environments. In the most spectacular case, a channel, several tens of metres wide and infilled with stromatoporoids, is incised in a peritidal cyclic complex. The successions investigated exhibit sedimentary features that are diagnostic of onshore redeposition. Independently of the scale of the recorded sedimentary events, the onshore redeposition was caused by factors with energy levels exceeding those of average storms, probably by hurricanes or even tsunami waves. The dynamic nature of some of the stromatoporoid beds has to be taken into account when constructing the curves illustrating bathymetrical and facies development of the Silurian succession of Podolia. The genesis of lens-shaped stromatoporoid beds, elongated depending on their origin, either parallel or perpendicular to the facies belts, should be considered an important factor in reconstructions of the depositional architecture of sedimentary hydrocarbon collectors.     

Sedimentology and stromatoporoid palaeoecology of Frasnian (Upper Devonian) carbonate mounds in southern Belgium

Da Silva, A.‐C., Kershaw, S. & Boulvain, F. 2011: Sedimentology and stromatoporoid palaeoecology of Frasnian (Upper Devonian) carbonate mounds in southern Belgium. Lethaia, Vol. 44, pp. 255–274. Stromatoporoids are the most abundant large skeletal organisms in middle Frasnian carbonate mound environments of southern Belgium. They occur in environments ranging from flank and off‐mound, mound core, shallow mound and restricted mound. A detailed log and comprehensive sampling of stromatoporoids in a single section cutting through all middle Frasnian mound levels in La Boverie–Rochefort Quarry, near Rochefort and Dinant reveals a stromatoporoid assemblage comprising 10 genera; 472 samples, containing an overall total of 3079 stromatoporoids (including complete and fragmented specimens) have been studied. The following list gives abundance using numbers of specimens and areas of total stromatoporoid area on outcrop surfaces (% number; % area in cm²): Actinostroma (0.4; 9.2), Amphipora (15.5; 1.7), Atelodictyon (0.2; 4.4), Clathrocoilona (0.3; 0.5), Euryamphipora (13.7; 0.7), Idiostroma (2; 1.9), Salairella (1.2; 9.6), branching Stachyodes (43.2; 59.1), laminar Stachyodes australe (1.9; 1.3), Stictostroma (4.8; 13.1) and Trupetostroma (0.2; 0.8), showing that Stachyodes is approximately half of the total assemblage. Deeper environments contain more abundant low profile forms, shallow water facies contain more domical and bulbous forms; branching forms are ubiquitous. Low profile stromatoporoids are likely to have been important sediment stabilizers that may have led to expansion of the carbonate factory, and they may have therefore contributed to the structural building of the mounds. Stromatoporoid‐coral intergrowths are observed in only Stictostroma suggesting that there is a close biological relationship between them; however, stromatoporoid skeletons in almost all cases appear to be unaffected by the presence of intergrown corals, suggesting they were commensals. □Frasnian, Late Devonian, mounds, palaeoecology, stromatoporoid.     

Synthesis and problematic crystal structures of [Al(CH3CN)6][MCl6]3(CH3CN)3 (M=Ta, Nb or Sb)

Compounds of formula [Al(CH₃CN)₆][MCl₆]₃(CH₃CN)₃ (M=Ta (1); Nb (2); Sb (3)) have been synthesized from the reactions of MCl₅ and AlCl₃ in acetonitrile and characterized by X-ray crystallography. Complex 1 crystallizes in the tetragonal space group P4/mbm with a = B = 10.408(2), C = 7.670(3) Å, V = 830.9(4) ų and Z = 2/3. Complex 2 crystallizes in the tetragonal space group P4/mnc with a = B = 330(a), C = 15.320(3) ų V = 1634.8(4) ų and Z = 4/3. Complex 3 also crystallizes in the tetragonal space group P4/mnc with a = B = 10.313(1), C = 15.238(2) Å, V = 1621.0(1) ų and Z = 4/3. The non-integer Z values for complexes 1–3 result unusual problems of disorder and/or twinning in these crystal structures due to their high symmetry. The M---Cl distances range from 2.329(3) Å in the Ta complex to 2.355(1) Å in the Sb complex, while the Al---N distances are similar in all three complexes, ranging from 1.92(1) to 1.97(1) Å, respectively. Complexes 1–3 are the first structurally characterized complexes that contain a (hexaacetonitrile)aluminum(III) cation.     

Stromatoporoid-coral intergrowths in a Silurian biostrome

Four stromatoporoid species from a stromatoporoid biostrome in the middle Ludlow Hemse Beds, Gotland, Sweden, show intergrowths with syringoporid tabulate and rugose corals, and indicate close relationships between particular coral and stromatoporoid species. The stromatoporoid Clathrodictyon convictum always contains ?Syringopora and this tabulate is rarely found in the other stromatoporoids. C. convictum is also closely associated with Tryplasma flexuosum (rugosa) while Petrozium pelagicum (rugosa) occurs only in the stromatoporoids Plectostroma intermedium and Parallelostroma typicum. The microstructure of ?Syringopora within the stromatoporoids is composed of an inner lamellar layer and an outer radial layer of calcite crystals. Diagenetic alteration has affected the microstructure which differs from recently described Devonian forms having only a radial layer. This shows variability in the structure of the tabulates within stromatoporoids. Information is sparse on the range of such variation and assessment of the relative importance of taxonomic, palaeoenvironmental and diagenetic effects is not possible in the present sample. No evidence is found to prove the precise nature of the relationships; they were not parasitic but may have been mutually symbiotic, or (most probably) commensal. The results suggest that the corals selected the most suitable stromatoporoid species for their requirements. Stromatoporoid morphology may have had an important influence on the association, where corals are more abundantly associated with those stromatoporoid species which adopted a high profile. Overall the associations appear to have allowed the corals to explore higher energy habitats otherwise unavailable to their delicate branching structure.     

Size and shape distribution of level-bottom tabulate corals and stromatoporoids (Silurian)

Baarli, B. G., Johnson, M. E. & Keilen, H. B. 1992 07 15: Size and shape distribution of level-bottom tabulate corals and stromatoporoids (Silurian).
Size and shape distribution of tabulate coral and stromatoporoid faunas were studied at two Lower Silurian sections in Norway on the Baltic platform and one section in eastern Iowa on the Laurentian platform. All the sections are dominated by storm beds with predominantly shallowing upward features; they differ from one another in clastic content and proximity to land. Most of the fauna lived below normal wave-base, but within the photic zone, on fine grained and firm bottoms. In all three localities, size clearly increases up-section for stromatoporoids, favositids, and heliolitids but it decreases for halysitids in the Oslo region. Sediment influx worked negatively on size but generally not so much as to affect average size. lurbulence in combination with decreasing sediment influx affected the size decrease in heliolitids up section. Nutrients and turbidity were of minor importance as growth controlling factors. Light intensity is the only factor that shows a pattern consistent with increased size up-section. Sediment influx alfected fauna composition and shape: heliolitids had the highest sediment tolerance and stromatoporoids had the lowest. Ragged skeletons were linked to tempestites. Corals and stromatoporoids reveal a population-specific response to environmental change, largely independent of benthic assemblage zones or communities. Tabulate corals, stromaroporaids, bathymetry, size variation. clastic input, benthic assemblages .     

Systematics and phylogenetic implications of the haplosclerid stromatoporoid Newellia mira nov. gen.

Wood, Rachel, Reitner, Joachim & West, Ronald R. 1989 01 15: Systematics and phylogenetic implications of the haploslerid stromatoporoid Newellia mira nov. gen. Lethaia, Vol. 22, pp. 85–93. Oslo. ISSN 0024–1164. The presence of spicules in a Palaeozoic stromatoporoid is here confirmed. Parallelopora mira Newell, 1935 from the Upper Carboniferous of the U.S.A. is redescribed as a calcified haplosclerid sponge with a primary siliceous spicule framework of isodictyally arranged styles, sub-tylostyles and strongyles and a secondary calcareous skeleton of stromatoporoid grade and probable aragonitic original mineralogy. P. mira is placed within a new genus Newellia, and family, the Newellidae. This form is postulated to have possessed large amounts of collagenous organic material which enveloped and bound the spicular framework in place. By the draping outline of the calcareous skeleton around the spicule framework and by analogy with the Recent demosponge genus Vaceletia, the calcareous skeleton is suggested to have formed by the direct mineralization of this collagenous template. Newellia mira nov. gen. is further proposed to constitute a member of a new clack of haplosclerid stromatoporoids, together with Euz-Miella erenoensis (Lower Cretaceous); a clade with some similarity to Recent non-calcified forms, e.g. Adocia. Most notably, the presence of different calcareous skeleton mineralogies and possibly microstructures in these two forms suggests the independent development of a calcareous skeleton at different times within this spicule clade. Demosponges appear to have produced calcareous skeletons independently in many different spicule clades. Calcified demosponges are now known from the Hadro-merida (Lower carboniferous; Upper Cretaceous - Recent), Axinellida (Upper Triassic - Lower Cretaceous; Upper Cretaceous; Recent), Poecilosclerida (Recent) as well as the Haplosclerida (Upper Carboniferous - Lower Cretaceous; Recent).□Upper Carboniferous, stromatoporoid, spicules, haplosclerid demosponges, calcareous skeleton biomineralization, demosponge clades, polyphyly.     

Facies and paleoecology of the late ordovician (Caradoc-Ashgill) stromatoporoid bioherms of Tasmania, Australia

Summary Stromatoporoids, together with other sedentary organisms, form bioherms in the Ordovician Gordon Group which were deposited on a carbonate platform of the Western Tasmanian Terrane. The shallow marine carbonates of the older formations show monotonous lithofacies and biota. The variety of the lithofacies and the diversity of sedentary organisms increases in the younger formations which exhibit evidence of subaerial exposure (fissure fillings and mud-cracks). These phenomena partly reflect the tectonic history of the Western Tasmania Terrane, and probably indicate a general increase in amplitude of sea-level change during the late Ordovician (Caradoc-Ashgill). The bioherms are most frequent in the uppermost horizons (the Den Formation—late Caradoc to early Ashgill?), where the outerops exhibit floatstone and bindstone fabrics. Stromatoporoids and corals construct generally small-scale (less than several meters in width and less than 1 m in height) binding structure. Based on growth forms, stromatoporoid genera are assigned to two morphotypes. Morphotype A generally shows laminar to low domical forms (low height/width ratio) exhibiting ragged margins and sediment inclusions within skeletons. In contrast, morphotype B consists of high domical growth forms (high height/width ratio) and lacks sediment inclusions. These differences in growth forms are interpreted to reflect different modes of biomineralization, together with environmental preferences of the individual organisms. Results of this study and previous publications, overall suggest a progressive development and diversification of biohermal biota in the middle to upper Ordovician of Tasmania. The scale and diversity of the Tasmanian bioherms are probably much smaller than the bioherms and reefs of the younger ages (Silurian and Devonian), and for stromatoporoids, the tendency of diversification is consistent with those of the other Ordovician sections. The Gordon Group provides useful information regarding the early evolutionary history of the Ordovician-Devonian reef-forming communities.     

Biomechanical analysis of passive flow of stromatoporoids — morphologic, paleoecologic, and systematic implications

Boyajian, George E. & LaBarbera, Michael 1987 07 15: Biomechanical analysis of passive flow of stromatoporoids - morphologic, paleoecologic, and systematic implications.
Investigation of the functional significance of astrorhizae (surficial canals) in some stromatoporoids is necessary to understand the structure and evolutionary affinities of these organisms. To this end, scale models of stromatoporoids with mamelons and astrorhizae were subjected to laminar flow conditions within a flow tank. Flow patterns were traced using dye streams. Dye was observed to enter the distal ends of the astrorhizae and flow to the top of the mamelon (mounds from which astrorhizae radiate) where it entered the overlying current and was removed. Similar flow patterns were observed in Living sclerosponges which display astrorhizal and mamelon structures. Excurrent (dyed) water was not refiltered by the model, or Living organism, thus demonstrating the ability of astrorhizae to function efficiently as excurrent canals. In the model viscous entrainment may aid the flow, but pressure differentials due to the velocity gradient above the mamelons account for most of the flow. In living sclerosponges, active pumping by the living organism accounts for most of its flow; passive mechanisms aid to an unknown degree. If stromatoporoid morphology is plastic and dependent on local environmental influences, local paleocurrent velocities may be deduced by examining the height and spacing of mamelons in fossil stromatoporoids; consequently, mamelons should not be. used as criteria in stromatoporoid systematics. These findings are consistent with Steam's reconstruction of the stromatoporoid animal and his proposed function of astrorhizae.     

Synthesis and characterization of SrCu2(O2CR)3(bdmap)3 and Bi2(O2CCH3)4(bdmap)2(H2O) (R = CH3, CF3; bdmap = 1,3-bis(dimethylamino)-2-propanolato)

New mixed metal complexes SrCu₂(O₂CR)₃(bdmap)₃ (R = CF₃ (1a), CH₃ (1b)) and a new dinuclear bismuth complex Bi₂(O₂CCH₃)₄(bdmap)₂(H₂O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF₂ and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi₂O₃ at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm⁻¹. Crystal data for 1a: C₂₇H₅₁N₆O₉F₉Cu₂Sr/THF, monoclinic space group P2₁/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) ų, Z = 2; for 1b: C₂₇H₆₀N₆O₉Cu₂Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) ų, Z = 8; for 2: C₂₂H₄₈O₁₁N₄Bi₂, monoclinic space group P2₁/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) ų, Z = 4.     

Molecular structures and some properties of tris(2-aminoethyl) amine cobalt(III) complexes with thiocarboxylato-O,S such as 3-mercaptopropionato, 2-mercaptoacetato and their derivatives

Cobalt(III) complexes with a thiolate or thioether ligand, t-[Co(mp)(tren)]⁺ (2), t-[Co(mtp)(tren)]²⁺ (1Me) and t-[Co(mta)(tren)]²⁺ (2Me), (mp = 3-mercaptopropionate, MA = 3-(methylthio)propionate and MTA = 2-(methylthio)acetate) have been prepared in aqueous solutions. The crystal structures of 1, 2, 1Me and 2Me were determined by X-ray diffraction methods. The crystal data are as follows, t-[Co(mp)(tren)]ClO₄ (1CIO₄): monoclinic, P2₁/n, A = 10.877(8), B = 11.570(4), c = 12.173(7) Å, β = 92.20(5)°, V = 1531(1) ų, Z = 4 and R = 0.060; t-[Co(ma)(tren)]Cl·3H₂O (2Cl·3H₂O): monoclinic, P2₁/n, a = 7.7688(8), B = 27.128(2), C = 7.858(1) Å, β = 100.63(1)°, V = 1627.7(3) ų, Z = 4 and R = 0.066; (+)₄₆₅^CD-t-[Co(mtp)(tren)](ClO₄)₂ ((+)₄₆₅^CD-1Me(ClO₄)₂): orthorhombic, P2₁2₁2₁, A = 10.6610(7), B = 11.746(1), C = 15.555(1) Å, V = 1947.9(3) ų, Z = 4 and R = 0.068; (+)₄₆₅^CD-t-[Co(mta)(tren)](ClO₄)₂ ((+)₄₆₅^CD-2Me(ClO₄)₂): orthorhombic, P2₁2₁2₁, a = 10.564(1), B = 11.375(1), C = 15.434(2) Å, V = 1854.7(4) ų, Z = 4 and R = 0.047. All central Co(III) atoms have approximately octahedral geometry, coordinated by four N, one O, and one S atoms. All of the complexes are only isomer, of which the sulfur atom in the didentate-O,S ligands are located at the trans position to the tertiary amine nitrogen atom of tren. 1 and 1Me contain six-membered chelate ring, and 2 and 2Me do five-membered chelate ring in the didentate ligand. The chirality of the asymmetric sulfur donor atom in (+)₄₆₅^CD-1Me is the S configuration and that in (+)₄₆₅^CD-2Me is the R one. The ¹H NMR, ¹³C NMR and electronic absorption spectral behaviors and electrochemical properties of the present complexes are discussed in relation to their stereochemistries.     

Occurrence of Giant Borings of Osprioneides kampto in the Lower Silurian (Sheinwoodian) Stromatoporoids of Saaremaa,Estonia

The distribution of Osprioneides is more environmentally limited than that of Trypanites in the Silurian of Baltica. Osprioneides probably occurred only in large hard substrates of relatively deepwater muddy bottom open shelf environments. Osprioneides were relatively rare, occurring in 4.7% of all stromatoporoid specimens in that environment, in contrast to small Trypanites-Palaeosabella borings, which occur in 88.4% of stromatoporoids and 88.9% of heliolitid corals. Osprioneides is reported only from the lower Sheinwoodian stromatoporoids of the exposed Silurian of Saaremaa (Wenlock to Pridoli). Osprioneides borings probably played a minor role in the general bioerosion in the Silurian of Baltica.