bibliography - various topics
Varia / 21st December 2016
BOVER ARNAL T., PASCUAL-CEBRIAN E., SKELTON P. W., GILI E., SALAS R. 2015. Patterns in the distribution of Aptian rudists and corals within a sequence-stratigraphic framework (Maestrat Basin, E Spain). Sedimentary Geology 321: 86-104.
The ecological zonation of, and environmental controls on rudist and coral assemblages on carbonate platforms of the Old World have received more attention for Late Cretaceous examples than for their Early Cretaceous counterparts. This study accordingly investigates the vertical and lateral distribution of Aptian rudist bivalves and scleractinian corals on a carbonate platform succession from the western Maestrat Basin (E Iberian Peninsula). Here, colonial corals grew profusely on an isolated platform top environment during an earliest highstand stage of a long-term trend of relative sea level, as well as on marly slope settings during higher-frequency transgressive pulses. During the later highstand stage within a longer-term relative sea-level cycle, a facies belt dominated by autochthonous rudist bivalves overlaid the coral meadow that had developed on the isolated platform top. The internal part of this carbonate platform with rudists is dominated by slender elevator caprinids such as Caprina parvula, whereas requieniids and polyconitids predominate in the external zone. The abundance of caprinids in the internal platform is remarkable given that caprinid lithosomes of late Early Aptian age are usually rare in the northern margin of the Tethys. The proliferation of caprinids in this case was probably favoured by the apparently more isolated nature of the carbonate platform. On the slopes, the coral communities that flourished during higher-frequency transgressive pulses are overlain by carbonates with rudists, mainly requieniids, shed from the platform top during normal and forced regressive higher-frequency changes of relative sea level. Accordingly, the vertical change from coral-dominated to rudist-dominated facies in both platform top and slope settings records progradation. To decipher the long-term relative sea-level changes that controlled the deposition of this carbonate succession, a sequence stratigraphic analysis was performed. Two depositional sequences including a late Early Aptian (intra Dufrenoyia furcata Zone) forced regressive stage of relative sea level, which subaerially exposed and incised the Early Aptian succession to a depth of 21m, were recognised. The incisions were back-filled with peritidal deposits during the subsequent marine onlap. The rudist- and coral-bearing carbonates were deposited a long platform top to slope profiles lacking a barrier margin, and hence, lagoon environments. [original abstract; Löser]
BRENNER L. D., LINSLEY B. K., DUNBAR R. B., WELLINGTON G. 2016. Coral δ18O evidence for Pacific Ocean mediated decadal variability in Panamanian ITCZ rainfall back to the early 1700s. Palaeogeography, Palaeoclimatology, Palaeoecology 449: 385-396 (1 May 2016).
[keywords: Coral; Porites; Panama; Intertropical convergence zone; Pacific decadal oscillation]
In Central America, seasonal and interannual shifts in the position of the Intertropical Convergence Zone (ITCZ) control the hydrologic budget. To better understand long-term changes in regional ITCZ-driven precipitation we re-examined a coral δ18O record from a Porites lobata coral head near Secas Island (Core ID: S1) (7°59' N, 82°3' W) in the Gulf of Chiriqui on the Pacific side of Panama. Linsley et al., (1994) originally published the 277-year time series and first described the presence of a narrow-band decadal cycle (period near 9-12 years) in δ18O. The original study did not present potential drivers for the decadal cycle, although they ruled out the influence of the sun spot cycle. Our re-analysis of this record supports the original interpretation that coral δ18O is largely responding to variations in precipitation and associated river discharge, but with a new proposed mechanism to explain the decadal mode. There is no similar decadal cycle in gridded instrumental sea surface temperature from the area, suggesting that the decadal coral δ18O signal results from hydrologic changes that influence coastal δ18Oseawater. The decadal component in S1 δ18O is also coherent with a decadal mode embedded in the Pacific Decadal Oscillation (PDO) Index that we suggest has tropical origins. We speculate that the coral's temporary δ18O deviation (1900-1930) in the decadal mode from the corresponding bands in rainfall and the PDO can be ascribed to a weak PDO in addition to local Panama gap wind variability and its effect on moisture transport from the Atlantic to the Pacific. Ultimately, the Secas Island coral δ18O series records ITCZ-driven precipitation dictated by both the Atlantic and Pacific basins. [original abstract; Wrzolek]
CORONADO I., PEREZ-HUERTA A., RODRIGUEZ S. 2015. Computer-integraded polarisation (CIP) in the analysis of fossils: a case study in a Palaeozoic coral (Sinopora, Syringoporicae, Carboniferous). Historical Biology 27, 8: 1098-1112.
Computer-integrated polarisation (CIP) method has been applied satisfactorily in the study of fossils skeletons of Sinopora (tabulate coral, Auloporida, Carboniferous). A previous characterisation of sample by scanning electron microscopy, atomic force microscopy and cathodoluminescence (CL) with the purpose of distinguishing the diagenetical alteration was done. Subsequently, a crystallographic comparison between CIP and electron-backscattering diffraction has been made getting a very good correlation between both methods. The CIP method allows obtaining c-axis orientation images, pole figures, and measure and mapping the misorientation of uniaxial biominerals in recent and fossil skeletons. This technique can only be used in uniaxial biominerals (calcite, quartz and hydroxylapatite), limiting its use for biaxial or bimineralic and polimineralic biominerals. CIP method has good spatial resolution (limited by camera); in our example 90 nm. The main advantage of this technique, versus other with similar properties, is the fast acquisition of data in low and high magnifications. This method does not require special treatment of samples and can be very useful for the analysis of microstructures in thin and ultra-thin sections. CIP method detects diagenetic alterations in fossil skeletons by modifications in the inner arrangement of biominerals, which combined with CL offers valuable geochemical and crystallographic information. [original abstract; Rodriguez]
COZAR P., GARCIA-FRANK A., SOMERVILLE I. D., VACHARD D., RODRIGUEZ S., MEDINA-VAREA P., SAID I. 2014. Lithofacies and biostratigraphical correlation of marine Carboniferous rocks in the Tindouf BAsin, NW Africa. Facies 60: 941-962.
Spatial and temporal variations of Carboniferous sediment accumulation within the northwestern part of the northern flank of the Tindouf Syncline in Saharan Morocco allowed to distinguish 16 lithofacies types. The predominant sedimentation pattern is cyclic, with the overall succession recording a major regressive trend. Outer platform siliciclastics in the lower part (Tournaisian and Viséan) pass up to middle and inner platform mixed siliciclastic and carbonate sediments (late Viséan-Serpukhovian) and finally to continental sandstones in the Bashkirian capping the marine carbonate sedimentation. The lack of similarities in a correlation with southern outcrops in the Tindouf Syncline suggests tectonically controlled sedimentation. The upper Tournaisian to lower Bashkirian succession records the incipient uplift of the Anti-Atlas Mountains, changing the paleogeography and, therefore, affecting the paleoecologic conditions, as well as the sedimentary environments in the Tindouf Basin. It is suggested that from the Serpukhovian onwards, much of the Anti-Atlas was uplifted, leading to subaerial conditions, while during the late Viséan, only a few small inliers had emerged. Although the number of Proterozoic emergent inliers of the Anti-Atlas is unknown, during the late Viséan, the Anti-Atlas Mountain belt is regarded as an emerging structure, with a distinct influence on the paleobiogeography of the region. [original abstract; Rodriguez]
COZAR P., SOMERVILLE I. D., VACHARD D., CORONADO I., GARCIA-FRANK A., MEDINA-VAREA P., SAID I., Del MORAL B., RODRIGUEZ S. 2015 (in press). Upper Mississippian to lower Pennsylvanian biostratigraphic correlation of the Sahara Platform successions in the northern margin of Godwana (Morocco, Algeria, Libya). Gondwana Research. DOI: 10.1016/j.gr.2015.07.019.
Revision of several important Carboniferous stratigraphic successions in basins in the Saharan Platform allows us to propose distinct biostratigraphical boundaries for the upper Viséan, lower and upper Serpukhovian and lower Bashkirian, with the latter boundary separating upper Mississippian from lower Pennsylvanian strata. The boundaries are not only defined primarily by foraminifers but also incorporate ammonoid and conodont data. This study shows that the positioning of some boundaries differs significantly from previous studies in the region. For the studied interval, it can be recognized that two well-defined tectonic events were widespread in the entire Sahara Platform: a mostly late Viséan event and a latest Serpukhovian - early Bashkirian event. Both tectonic events show a marked tendency to become younger eastward, and they are compared to the intra-Viséan phase of the Variscan Orogeny and the main phase of this orogeny, respectively. [original abstract; Rodriguez]
DeLONG K., MAUPIN C. R., FLANNERY J. A., QUINN T. M., SHEN Chuan-Chou 2016. Refining temperature reconstructions with the Atlantic coral Siderastrea siderea. Palaeogeography, Palaeoclimatology, Palaeoecology 462, 15 November 2016, pp 1-15; http://dx.doi.org/10.1016/j.palaeo.2016.08.028
[keywords: Siderastrea siderea; Sr/Ca; δ18O; δ13C; Dry Tortugas; Sea surface temperature]
Developing coral-based temperature reconstructions for a particular coral species requires determining the optimal sampling path orientation and resolution for geochemical analysis to avoid sampling artifacts and to increase reproducibility. Furthermore, a robust coral archive should have high intracolony and intercolony reproducibility for determining the common environmental signal. Here we assessed sampling path orientation and sampling resolution for Siderastrea siderea colonies within the Dry Tortugas National Park in the Gulf of Mexico (24°42'N, 82°48'W) to determine the optimal sampling protocol and to assess reproducibility of coral Sr/Ca, δ18O, and δ13C. We identified a sampling artifact due to extracting samples from the coral columella resulting in cold bias up to 5.2 °C in coral Sr/Ca. We found no shift to higher coral Sr/Ca values (i.e., colder) for years with a 50% reduction in average extension rate (2.1 mm year -1) or for sampling along paths up to 70° off the vertical axis of the colony. Our sampling resolution comparison (1900-1993) indicated that the resolution of ~ 6 samples year -1 used in a previous study for coral Sr/Ca and δ18O may not capture seasonal extremes and thus produces muted seasonal cycles, but that resolution is not biased towards one season. Reproducibility or average deviations, assessed using absolute differences (AD) and root mean square (RMS), among the monthly resolved coral Sr/Ca records for intracolony to intercolony comparisons were within 2σ of our analytical precisions. Average deviations were reduced by 19 to 61% when assessing interannual variability (36-month smoothed and mean annual) suggesting that subannual dating uncertainties (i.e., assigning a coral Sr/Ca value to a particular month) were the largest source of error in our monthly resolved coral Sr/Ca reconstruction. Similarly, coral δ18O was reproducible within 2σ of our analytical precision (AD = 0.10‰ and RMS = 0.07‰); however, coral δ13C and linear extension records were not reproducible. Our assessment of coral geochemical variations from multiple S. siderea colonies suggests this species is suitable for paleoclimatic reconstructions, including subfossil corals and microatoll colonies that grow laterally.
DENAYER J., ARETZ M., POTY E., MOTTEQUIN B. 2016. Royseux: a palaeobiodiversity hotspot in the Late Visean (Carboniferous) of Belgium. Geologica Belgica 19, 1-2: 7-20.
[keywords: biodiversity, disparity, hotspot, endemism, corals, brachiopods, reef, Carboniferous]
Biodiversity hotspots are defined as areas of unusually high biological diversity. This definition is less clear for palaeohotspots but the Royseux locality in Southern Belgium is interpreted as such a site because of the large number of coral species that co-occur within a small area and short time interval. Forty-one species (29 genera) of rugose, tabulate and heterocorallia corals are known within a 6 m-thick 4th order parasequence (100 kyr). These numbers increase to 50 species in 30 genera if the entire succession is considered. Consequently, Royseux is regarded as the richest site for late Visean coral diversity on a global scale. Comparison with other sites from Spain, Morocco, the British Isles, and eastern Australia confirms this view. The diversity of brachiopods (at least 18 species within 16 genera) and other invertebrates is also assessed. The great palaeobiodiversity is tentatively explained by the interplay of several global and local causes, including high late Visean biodiversity at the global scale associated with tectonically and sedimentary driven micro-environment differentiation. Conversely, the Royseux locality has yielded few endemic taxa. [original abstract; Wrzolek]
DENAYER J., MOTTEQUIN B., PRESTIANNI C. 2015. IGCP596-SDS Symposium, Climate Change and Biodiversity patterns in the Mid-Palaeozoic, Brussels, September 2015, Field guidebooks. STRATA 17, 81 pp.
[contents of the guidebook volume; supplied by J. Denayer]
- Denayer J., Mottequin B., Marion J.-M., Devleeschouwer X. & Prestianni C.: The Middle Devonian succession in the Dinant Synclinorium
- Mottequin B., Denayer J., Poty E. & Devleeschouwer X.: Middle to Upper Frasnian succession, Kellwasser events and the Frasnian–Famennian Boundary in the Namur–Dinant Basin
- Denayer J., Mottequin B., Dreesen R., Marion J.-M., Olive S. & Prestianni C.: The Famennian succession: marine, continental and reefal facies in the Dinant Synclinorium and Vesdre area
- Denayer J., Prestianni, C., Sautois M., Poty E. & Mottequin B.: The Devonian – Carboniferous Boundary and the Lower Carboniferous succession in the type area
FLANNERY J. A., RICHEY J. N., THIRUMALAI K., POORE R. Z., DeLONG K. L. 2017. Multi-species coral Sr/Ca-based sea-surface temperature reconstruction using Orbicella faveolata and Siderastrea siderea from the Florida Straits. Palaeogeography, Palaeoclimatology, Palaeoecology 466, 15 January 2017, pp 100-109; http://dx.doi.org/10.1016/j.palaeo.2016.10.022
[keywords: Sclerochronolgy; Paleoclimatology; Atlantic multidecadal oscillation; Sr/Ca; Orbicella faveolata; Siderastrea siderea]
We present new, monthly-resolved Sr/Ca-based sea-surface temperature (SST) records from two species of massive coral, Orbicella faveolata and Siderastrea siderea, from the Dry Tortugas National Park, FL, USA (DTNP). We combine these new records with published data from three additional S. siderea coral colonies to generate a 278-year long multi-species stacked Sr/Ca-SST record from DTNP. The composite record of mean annual Sr/Ca-SST at DTNP shows pronounced decadal-scale variability with a range of 1 to 2 °C. Notable cool intervals in the Sr/Ca-derived SST lasting about a decade centered at ~ 1845, ~ 1935, and ~ 1965 are associated with reduced summer Sr/Ca-SST (monthly maxima < 29 °C), and imply a reduction in the spatial extent of the Atlantic Warm Pool (AWP). There is significant coherence between the composite DTNP Sr/Ca-SST record and the Atlantic Multidecadal Oscillation (AMO) index, with the AMO lagging Sr/Ca-SST at DTNP by 9 years. Low frequency variability in the Gulf Stream surface transport, which originates near DTNP, may provide a link for the lagged relationship between multidecadal variability at DTNP and the AMO.
FRANKOWIAK K., KRET S., MAZUR M., MEIBOM A., KITAHARA M. V., STOLARSKI J. 2016. Fine-scale skeletal banding can distinguish symbiotic from asymbiotic species among modern and fossil scleractinian corals. PLoS ONE 11 e0147066, doi:10.1371/journal.pone.0147066
Understanding the evolution of scleractinian corals on geological timescales is key to predict how modern reef ecosystems will react to changing environmental conditions in the future. Important to such efforts has been the development of several skeleton-based criteria to distinguish between the two major ecological groups of scleractinians: zooxanthellates, which live in symbiosis with dinoflagellate algae, and azooxanthellates, which lack endosymbiotic dinoflagellates. Existing criteria are based on overall skeletal morphology and bio/geo-chemical indicators - none of them being particularly robust. Here we explore another skeletal feature, namely fine-scale growth banding, which differs between these two groups of corals. Using various ultra-structural imaging techniques (e.g., TEM, SEM, and NanoSIMS) we have characterized skeletal growth increments, composed of doublets of optically light and dark bands, in a broad selection of extant symbiotic and asymbiotic corals. Skeletons of zooxanthellate corals are characterized by regular growth banding, whereas in skeletons of azooxanthellate corals the growth banding is irregular. Importantly, the regularity of growth bands can be easily quantified with a coefficient of variation obtained by measuring bandwidths on SEM images of polished and etched skeletal surfaces of septa and/or walls. We find that this coefficient of variation (lower values indicate higher regularity) ranges from ~40 to ~90% in azooxanthellate corals and from ~5 to ~15% in symbiotic species. With more than 90% (28 out of 31) of the studied corals conforming to this microstructural criterion, it represents an easy and robust method to discriminate between zooxanthellate and azooxanthellate corals. This microstructural criterion has been applied to the exceptionally preserved skeleton of the Triassic (Norian, ca. 215 Ma) scleractinian Volzeia sp., which contains the first example of regular, fine-scale banding of thickening deposits in a fossil coral of this age. The regularity of its growth banding strongly suggests that the coral was symbiotic with zooxanthellates.
FRANKOWIAK K., WANG X.-T., SIGMAN D. M., GOTHMANN A. M., KITAHARA M. V., MAZUR M., MEIBOM A., STOLARSKI J. 2016. Photosymbiosis and the expansion of shallow-water corals. Science Advances 2 (11), e1601122, doi: 10.1126/sciadv.1601122
Roughly 240 million years ago (Ma), scleractinian corals rapidly expanded and diversified across shallow marine environments. The main driver behind this evolution is uncertain, but the ecological success of modern reefbuilding corals is attributed to their nutritional symbiosis with photosynthesizing dinoflagellate algae. We show that a suite of exceptionally preserved Late Triassic (ca. 212 Ma) coral skeletons from Antalya (Turkey) have microstructures, carbonate 13C/12C and 18O/16O, and intracrystalline skeletal organic matter 15N/14N all indicating symbiosis. This includes species with growth forms conventionally considered asymbiotic. The nitrogen isotopes further suggest that their Tethys Sea habitat was a nutrient-poor, low-productivity marine environment in which photosymbiosis would be highly advantageous. Thus, coral-dinoflagellate symbiosis was likely a key driver in the evolution and expansion of shallow-water scleractinians.
GOTHMANN A. M., BENDER M. L, BLATTLER C. L., SWART P. K., GIRI S. J., ADKINS J. F., STOLARSKI J., HIGGINS J. 2016. Calcium isotopes in scleractinian fossil corals since the Mesozoic: implications for vital effects and biomineralization through time. Earth and Planetary Science Letters 444: 205-214, doi:10.1016/j.epsl.2016.03.012
We present a Cenozoic record of δ44/40Ca from well preserved scleractinian fossil corals, as well as fossil coral δ44/40Ca data from two time periods during the Mesozoic (84 and 160 Ma). To complement the coral data, we also extend existing bulk pelagic carbonate records back to ~80 Ma. The same fossil corals used for this study were previously shown to be excellently preserved, and to be faithful archives of past seawater Mg/Ca and Sr/Ca since ~200 Ma (Gothmann et al., 2015). We find that the δ44/40Ca compositions of bulk pelagic carbonates from ODP Site 807 (Ontong Java Plateau) and DSDP Site 516 (Rio Grande Rise) have not varied by more than ~±0.20‰ over the last ~80 Myr. In contrast, the δ44/40Ca compositions of Mesozoic and Early Cenozoic fossil corals are ~1‰ lighter than those of modern corals. The observed change in coral δ44/40Ca does not likely reflect secular variations in seawater δ44/40Ca. Instead, we propose that it reflects a vital effect of calcification - specifically, a sensitivity of coral Ca isotope discrimination to changing seawater [Ca] and/or pH. Support for this hypothesis comes from the presence of an empirical correlation between our coral δ44/40Ca record and records of seawater [Ca] and pH since the Mesozoic (Lowenstein et al., 2003; Hönisch et al., 2012). We explore various mechanisms that could give rise to such a vital effect, including: (1) changes in calcification rate, (2) changes in proton pumping in exchange for Ca2+, (3) variable Rayleigh distillation from an isolated calcifying fluid, and (4) changes in the calcium mass balance of the extracellular calcifying fluid (termed here the “leaky Ca model”). We test for the dependence of seawater δ44/40Ca on external seawater [Ca] by measuring the δ44/40Ca of cultured corals grown in seawater solutions with [Ca] ranging from 10 to 15 mmol/kg. Corals grown under elevated [Ca] conditions show a slight, ~0.15‰ depletion of δ44/40Ca at higher seawater [Ca] - a supportive but not definitive result.
KOLODZIEJ B., IDAKIEVA V., IVANOV M., SALAMON K. 2016. New record of endolithic algae syn-vivo associated with an Early Cretaceous coral. Carnets de Geologie 16, 27: 633-640.
[keywords: microborings; euendoliths; symbiosis; corals; Barremian; Bulgaria]
Euendolithic microorganisms (boring endoliths) syn-vivo associated with modern corals are commonly reported, but their fossil record is extremely rare. This paper reports the new finding recognized in the colonial scleractinian coral Clausastrea saltensis from the Upper Barremian of Bulgaria. Large microborings (up to 50 μm, most ca. 15-25 μm in diameter) filled with calcite cement are distributed medially along coral septa of some corallites. Borings were produced by microeuendoliths growing from the skeleton interior outward during the life of the coral host. They are compared to traces produced by the recent oligophotic filamentous chlorophyte Ostreobium, which is known to be the most common skeleton-dwelling alga in modern living corals and regarded as neutral or beneficial to the coral. In terms of general morphology, diameter and distribution pattern, the borings are similar to those recently recognized in the Early Cretaceous microsolenid coral.
LABORDA-LOPEZ C., AGUIRRE J., DONOVAN S. K., NAVAS-PAREJO P., RODRIGUEZ S. 2015. Fossil assemblages and biostratigraphy of metamorphic rocks of the Nevado-Filábride Complex from Águilas tectonic arc (SE Spain). Spanish Journal of Paleontology 30, 2: 275-292.
Abundant marine macrofossils are present in graphitic marbles and calc-silicate schists belonging to the Veleta nappe of the Nevado-Filábride Complex (Internal Zones of the Betic Cordillera, SE Spain), in what is called the Águilas tectonic arc. These fossils have resisted metamorphism and deformation, and in some instances have been finely preserved. The fossil assemblages are dominated by crinoids, followed by minor cephalopods, brachiopods, rugose corals, and putative sections of trilobites. In addition to these confidently identified groups, there are other fossil represented, but deformation and extensive recrystallization have destroyed anatomical characters, hampering their taxonomic identification. Among the crinoids, the columnal parataxa Pentagonopentagonalis (col.) and Bystrowicrinus (col.) have been recognized. Planispiral cephalopods, assigned to either primitive ammonoids attributable to the order Agoniatitid (one of them being a possible member of the family Mimosphinctidae) or coiled nautilids, as well as orthoconid sections of possible orthoceratids or bactritids are present. Finally, there are rugose corals attributable to the family Phillipsastreidae, possibly Peneckiella. Among the remains with obscure taxonomic assignment, we recognize possible laminar calcareous algae and benthic foraminifers. Finally, irregular, massive structures showing a rough laminar organization and longitudinal tubes with rounded sections are found in some black marble beds. These can be identified either as possible chaetetids or bryozoans. The report of these taxa has limited the rocks studied to the Emsian, late Early Devonian. [original abstract; Rodriguez]
LEE M., ELIAS R. J., CHOH Suk-Joo, LEE Dong-Jin 2016. Insight from early coral-stromatoporoid intergrowth, Late Ordovician of China. Palaeogeography, Palaeoclimatology, Palaeoecology 463, 1 December 2016, pp 192-204; http://dx.doi.org/10.1016/j.palaeo.2016.10.010
[keywords: Symbiosis; Coral-stromatoporoid intergrowth; Tabulate coral; Clathrodictyid stromatoporoid; Ordovician; Paleoecology]
One of the earliest endosymbiotic associations with stromatoporoids occurs in the Late Ordovician Xiazhen Formation of southeastern China. Bajgolia, an auloporid tabulate coral characterized by dichotomous branching due to longitudinal fission, is represented by free-living as well as endobiontic forms in various lithofacies representing a wide range of environments. Only two of 11 stromatoporoid genera (Clathrodictyon and Ecclimadictyon) hosted Bajgolia, mainly in reef and related facies. Bajgolia-stromatoporoid associations occur occasionally in the lower part of the formation, but eventually become persistent in the upper part. Such associations were initiated by larval settlement of the coral on the growth surface of the stromatoporoid. Growth of Bajgolia usually kept pace with its host, but the coral's ability to change growth direction and grow faster prevented its envelopment and termination by the stromatoporoid, allowing the establishment and recurrence of an ongoing endosymbiotic relationship between the two organisms. Endobiontic Bajgolia was able to survive with its corallites protruding from the host; in some cases, the growth form of the stromatoporoid changed in response to the coral. The relationships between Bajgolia and stromatoporoids were probably commensal, but there is also evidence for mutualism and/or parasitism. Bajgolia-stromatoporoid associations represent an important stage in the development of complex ecological relationships and community structure, prior to the common and widespread syringoporid ("caunopore tubes")-stromatoporoid associations in the Siluro-Devonian.
LI Hao, LIN Changsong, ZHANG Yanmei 2012. Stratigraphic architecture and computer modelling of carbonate platform margin, late Ordovician Lianglitage formation, Central Tarim Basin. Journal of Earth Science 23, 4: 627-638.
[keywords: carbonate platform margin; depositional architecture; tectonic subsidence; accommodation modelling]
According to the different geometries and reflected characteristics in the seismic sections, the carbonate platform margin of the northern slope can be summarized as three basic depositional architectures in the Late Ordovician Lianglitage Formation of the Tazhong uplift. The type one mainly located in the west of the carbonate platform margin, and it showed obvious imbricate progradation from the interior to the margin of the platform. The type two was in the middle of the carbonate platform margin, which showed retrogradational stacking pattern in the same transgressive systems tract period, and the slope strata of the platform margin showed progradational sequence in the highstand systems tract period. The type three located in the east of the carbonate platform margin, and it showed the parallel aggradational architecture. The crossing well section along the northern slope of the Tazhong carbonate platform showed that the depositional thickness became thinner from the east to the west. The thickest belt located in the east of the platform margin, and became thinner rapidly towards the basin and the platform interior. These indicated that the paleogeomorphology of the Tazhong uplift was probably high in the west and low in the east during the period of the Late Ordovician Lianglitage Formation. According to the interpretation of seismic profiles and the computer modelling result, the depositional architectures of sequence O3 /-2 showed aggradation, retrogradation and progradation from the east to the west of the carbonate platform margin during the transgression period. This meant that the accommodation became smaller gradually from the east to the west along the northern carbonate platform margin of the Tazhong uplift. The difference of the accommodation was probably caused by the difference of tectonic subsidence. Also, computer-aided modelling can be used to deeply understand the importance of various control parameters on the carbonate platform depositional architectures and processes. [original abstract; Wrzolek]
MA Xueping, GONG Yiming, CHEN Daizhao, RACKI G., CHEN Xiuqin, LIAO Weihua 2016. The Late Devonian Frasnian-Famennian Event in South China - Patterns and causes of extinctions, sea level changes, and isotope variations. Palaeogeography, Palaeoclimatology, Palaeoecology 448: 224-244 (15 April 2016).
[keywords: Upper Devonian; Kellwasser events; Mass extinction; South China; Diversity change; Biotic crisis]
The Frasnian-Famennian (F-F) event may be recognized in various facies areas in South China. In the pelagic cherty basin facies, both Lower and Upper Kellwasser events can seemingly be recognized. In the deeper water carbonate facies, the F-F event level is well controlled in light of conodont biostratigraphy. In the shallow water carbonate and mixed carbonate-shale facies, the F-F boundary may be defined by clear taxonomic distinction in benthic fossils (articulate brachiopods and corals) as well as evidence from minor pelagic fossils. Post-extinction recovery rate of benthic organisms differs in different facies settings and different taxonomic groups. In open shallow water platform to inter-platform depression areas, brachiopods seem to recover quickly, probably in the Middle Pa. triangularis Zone; benthic ostracodes seem to recover at a later stage; recovery of rugose corals did not happen until the uppermost Famennian. Three steps of the F-F mass extinction are postulated: 1) extinction of diverse brachiopods (including most atrypids); 2) extinction of pelagic conodonts; 3) extinction of both benthic faunas (very abundant and diverse rugose corals and ostracodes) and pelagic conodonts. Evidence of an end-Frasnian regression in South China is clear, particularly in shallow water settings. However, in deeper water settings, the picture is complicated, with evidence of both sea level rise and fall in the latest Frasnian. It may be assumed from overall data so far known that crustal evolution itself and associated multiple volcanic / hydrothermal activities may have mainly caused frequent and rapid climatically warming-cooling alterations and sea level changes as well as marine ecologic collapse (eutrophication, microbial blooming, seawater acidification, and anoxia), which may explain the F-F extinction pattern in South China. [original abstract; Wrzolek]
MARTINELLI J. C., MADIN J. S., KOSNIK M. A. 2016. Dead shell assemblages faithfully record living molluscan assemblages at One Tree Reef. Palaeogeography, Palaeoclimatology, Palaeoecology 457; 158-169.
[highlights: * High fidelity was found between live and dead assemblages. * Taphonomy accounts for < 20% of differences between live and dead assemblages. * Mollusk community composition suggests stability for at least 30 years. * Results suggest that reef sediments are useful for conservation paleobiology studies.]
PICKETT J. W. 2016. Settlement strategy in Symplectophyllum (Cnidaria, Rugosa). Geologica Belgica 19, 1-2: 43-56.
[keywords: Ontogeny, settlement strategy, Carboniferous, Syringopora, Symplectophyllum, mortality crisis, ecology, sweeper tentacles]
The early ontogeny of the solitary rugose coral Symplectophyllum from the late Tournaisian - early Visean of New South Wales is described. The genus is frequently associated with the phaceloid tabulate coral Syringopora, individuals of the former genus occurring within the coralla of the latter, and growing in tandem. A similar association also occurs between Symplectophyllum and the rugosan genera Cionodendron and Pickettodendron, though less commonly. The phaceloid genera suffer periodic mortality events, causing breaks in vertical growth; the settlement of Symplectophyllum larvae appears to be associated with these events. Larvae settle on algal incrustations of the epitheca of the phaceloid corals, not on the epitheca itself. The manner in which Symplectophyllum corallites acquired space for growth suggests the presence of sweeper tentacles in Rugosa. [original abstract; Wrzolek]
PRETKOVIC V., BRAGA J. C., NOVAK V., ROSLER A., RENEMA W. 2016. Microbial domes and megaoncoids in Miocene reefs in the Mahakam Delta in East Kalimantan, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 449: 236-245.
[highlights: * Microbialites occur in Langhian patch reefs within delta deposits in East Kalimantan. * Microbialites appear as low-relief domes and as large nodules, here named megaoncoids. * Flat-domed microbialites formed at the transition from reefs to fine siliciclastics. * Megaoncoids accumulated in a breccia laterally changing into coral boundstones. * Both types formed in shallow, turbid waters of the Miocene Mahakam delta.]
RODRIGUEZ S., SAID I., SOMERVILLE I. D., COZAR P., CORONADO I. 2016. Serpukhovian coral assemblages from Idmarrach and Tirhela Formations (Adarouch, Morocco). Geologica Belgica 19, 1-2: 29-42.
[keywords: Mississippian, Rugosa, Tabulata, palaeogeography, biostratigraphy, palaeoecology]
The Serpukhovian coral assemblages from Idmarrach and Tirhela formations (Adarouch, Morocco) have been studied. They yielded quite diverse assemblages with a total of 32 rugose and 1 tabulate species. The distribution of corals in the sections Idmarrach 1, 2, 3, and 4 and Tirhela 1 and 2 has been established, which include Serpukhovian and Bashkirian rocks. The Serpukhovian assemblages are composed mostly of species that have their higher abundance in the upper Visean. However, most of the recorded taxa in Adarouch have been already mentioned in Serpukhovian rocks from Britain, Moscow Basin, Urals, Donets Basin and other North African regions such as Tindouf and Bechar. Thus, their stratigraphic range is not expanded. The coral diversity is mainly concentrated in biostromes from the Idmarrach 1 section. However, the high total diversity is due to the combination of favourable depositional settings and a mixture in different beds of several ecological environments, such as coral shoals, protected lagoons and microbial mounds. Most Serpukhovian species have been recorded in areas from the western Palaeotethys previously mentioned. The total assemblage can be considered as typical for the late Mississippian in the western Palaeotethys. However, a small degree of isolation is registered by the absence in the Serpukhovian from Adarouch of the genera Lonsdaleia, Actinocyathus, Tizraia and Kizilia that have been recorded in other North African basins. That fact may be explained by the incipient rising of some areas as 'highs' due to the start of the collision between Gondwana and Laurasia. [original abstract; Wrzolek]
STEVENS C. H., CLITES E. C. 2016. Transfer of the Calvin H. Stevens Coral Collection to the University of California Museum of Paleontology, Berkeley, California. Journal of Paleontology 90, 1: 182.
Corals collected by Dr. Calvin H. Stevens and previously curated in the Geology Department, San Jose State University, San Jose, California, have been transferred to the University of California Museum of Paleontology, Berkeley, California. The collection consists of more than 850 hand samples and thin sections accumulated over a span of ~50 years. The majority of specimens are colonial forms from the Permian of western USA [initial part of a short note; Wrzolek]
STOLARSKI J., BOSELLINI F. R., WALLACE C. C., GOTHMANN A., MAZUR M., DOMART-COULON I., GUTNER-HOCH E., NEUSER R. D., LEVY O., SHEMESH A., MEIBOM A. 2016. A unique coral biomineralization pattern has resisted 40 million years of major ocean chemistry change. Scientific Reports 6, 27579; doi: 10.1038/srep27579
Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we show that the most diverse, widespread, and abundant reef-building coral genus Acropora (20 morphological groups and 150 living species) has not only survived these environmental changes, but has maintained its distinct skeletal biomineralization pattern for at least 40 My: Well-preserved fossil Acropora skeletons from the Eocene, Oligocene, and Miocene show ultra-structures indistinguishable from those of extant representatives of the genus and their aragonitic skeleton Mg/Ca ratios trace the inferred ocean Mg/Ca ratio precisely since the Eocene. Therefore, among marine biogenic carbonate fossils, well-preserved acroporid skeletons represent material with very high potential for reconstruction of ancient ocean chemistry.
VINN O. 2016. Symbiotic endobionts in Paleozoic stromatoporoids. Palaeogeography, Palaeoclimatology, Palaeoecology 453: 146-153.
[keywords: Symbiosis; Bioclaustrations; Stromatoporoids; Ordovician; Silurian; Devonian]
Stromatoporoids hosted a diverse fauna of symbiotic endobionts during the Silurian and Devonian. Assemblages of symbiotic endobionts from the Ordovician, Silurian and Devonian differ significantly. The only symbiotic association in the Ordovician is cornulitid-stromatoporoid. The diversity of Silurian and Devonian symbiotic associations is similar, but the taxonomic compositions of the Silurian (i.e. rugosans, syringoporids, cornulitids, lingulids, Chaetosalpinx and Helicosalpinx) and Devonian (i.e. syringoporids, Torquaysalpinx, Chaetosalpinx, Streptindytes, and rugosans) associations are different. Symbiotic corals dominated both Silurian and Devonian associations, rugosans dominated the Silurian associations, and syringoporids dominated the Devonian associations. [original abstract; Wrzolek]
VINN O. 2016. Tentaculitoid tubeworms as endobiotic symbionts of Paleozoic corals and sponges. Palaios 31, 9: 440-446.
Endobiotic tentaculitoids formed symbiotic associations with tabulates, heliolitids, rugosans, bryozoans, crinoids, stromatoporoids, and chaetetids from the Late Ordovician to the Carboniferous. The Ordovician was dominated by coral hosts, but there was a shift from mostly coral-based associations to stromatoporoid-based associations in the early Silurian. Specialization increased during the evolution of tentaculitoid symbiosis. In the Devonian, specialized symbiotic endobiont genera appeared which did not occur separately from their hosts. [original abstract; Wrzolek]
VINN O., ERNST A., TOOM U. 2016. Earliest symbiotic rugosans in cystoporate bryozoan Ceramopora intercellata Bassler, 1911 from Late Ordovician of Estonia (Baltica). Palaeogeography, Palaeoclimatology, Palaeoecology 461, 1 November 2016, pp 140-144; http://dx.doi.org/10.1016/j.palaeo.2016.08.016
[keywords: Symbiosis; Intergrowth; Bryozoans; Rugosans; Baltica; Katian]
The earliest known endobiotic rugose corals are recorded in the Katian of Estonia. Multiple rugosans were partially embedded in colonies of the cystoporate bryozoan Ceramopora intercellata Bassler, 1911, leaving only their apertures free on the bryozoan growth surface. Bodophyllum sp. and Lambelasma sp. are rugosans that formed a symbiotic association with C. intercellata which may have been mutualistic. Rugosans presumably benefitted from growth within the stable substrate provided by the bryozoan, while bryozoans presumably benefitted by protection against some types of predators. Symbiosis between rugosans and the bryozoan Ceramopora intercellata was most likely facultative.
VINN O., TOOM U. 2016. Rugosan epibionts on vertical stems from the Ludlow and Pridoli of Saaremaa, Estonia (Baltica). Palaios 31, 2: 35-40.
The earliest known rugosans attached syn vivo to vertical stems occur in the late Silurian of Saaremaa, Estonia. These rugosans display vertical to subvertical attachment scars and are more common in the Ludfordian than in the Pridoli. The unknown hosts provided a higher tier for the feeding, making the association beneficial for the rugosans. Several rugosans were themselves syn vivo encrusted by bryozoans and unknown endobiotic tubicolous organisms, possibly cornulitids. Estonian rugosans appear to have been host size selective and preferred substrates of certain size. Silurian symbiotic rugosans are more often endobionts in stromatoporoids than epibionts on the vertical stems. [original abstract; Wrzolek]
VINN O., WILSON M. A. 2016. Symbiotic interactions in the Silurian of Baltica. Lethaia 49, 3: 413-420.
[keywords: Endobionts; parasites; Silurian; stromatoporoids; symbiosis; tabulates; trace fossils]
Thirteen symbiotic associations occur in the Silurian of Baltica. Symbiosis was especially prominent among colonial animals, most commonly with stromatoporoids. These sponges hosted the most diverse fauna of endobiotic symbionts (including rugosans, Syringopora, 'polychaetes', cornulitids and lingulids). This pattern can be explained by the abundance of stromatoporoids in the Silurian of Baltica and their large skeletal volume, making them attractive hosts for smaller invertebrates. There is an evolutionary trend of an increasing number of different pairs of symbiotic taxa from the Llandovery to the Ludlow, with a remarkable increase in the Ludlow. This is likely related to an increase in the number of mutualistic taxa that could have had evolutionary advantages over organisms less amenable to symbiosis. The number of different pairs of symbiotic taxa also increased in the Wenlock, which may be linked to delayed recovery from the end-Ordovician mass extinction. [original abstract; Wrzolek]
WANG L., WIGNALL P. B., WANG Yongbiao, JIANG Haishui, SUN Yadong, LI Guoshan, YUAN Jinling, LAI Xulong 2016. Depositional conditions and revised age of the Permo-Triassic microbialites at Gaohua section, Cili County (Hunan Province, South China). Palaeogeography, Palaeoclimatology, Palaeoecology 443: 156-166.
[keywords: Permian–Triassic; Microbialite; Conodont; Dysoxic]
In many tropical shallow water regions the end-Permian mass extinction event occurs at the top fossiliferous packstone beds and is immediately followed by the development of microbialite facies. Both the age and redox conditions of the microbialite have been debated and both factors are addressed here in a study of the Gaohua section (Cili County, Hunan Province, China): specifically the size distribution of pyrite framboids and high-resolution conodont biostratigraphy. The framboids populations show a broad size range with examples up to 30 microns in diameter, and indicating dysoxic but not anoxic depositional conditions. More intense dysoxia is recorded in interbedded laminated micrites but not beds of giant ooids. Both the Hindeodus parvus zone and Isarcicella isarcica zones were established with the microbialite beds being confined to the H. parvus zone. Therefore, the formation of microbialite postdates the end Permian main mass extinction and records oxygen-poor conditions even in a shallow-water setting such as Gaohua section at Cili. [original abstract; Wrzolek]
WU Ya-Sheng, YU Gong-Liang, JIANG Hong-Xia, LIU Li-Jing, ZHAO Rui 2016. Role and lifestyle of calcified cyanobacteria (Stanieria) in Permian–Triassic boundary microbialites. Palaeogeography, Palaeoclimatology, Palaeoecology 448: 39-47.
[highlights: * The coccoid microfossils in the PTB microbialites in southern China are calcified sheaths of the extant unicellular cyanobacterium Stanieria; * The PTB Stanieria attached themselves only to densely packed phytoplanktons in bloom, in a "hitch-hiking" lifestyle; * Sheath calcification of Stanieria cells depends on high carbonate saturation of ambient water caused by phytoplanktonic blooms; * Calcified fossils of Stanieria cells can be indicative of ancient phytoplanktonic blooms; * Anoxia caused by phytoplanktonic blooms is favorable to preservation of Stanieria cells as fossils]
ZAIKA Yu. U. 2016. On exceptionally well preserved Paleozoic Tabulate corals redeposited in Pleistocene sands of Belarus. Baranavichy State University Herald. Series: Biological Sciences; Agricultural Sciences 2016: 20-26. [in Belarusian, with English abstract, figure captions and references]
[keywords: Paleozoic Tabulata corals, redeposition, Pleistocene, fast shore ice rafting]
Redeposited Paleozoic (mainly Ordovician and Silurian) Tabulata corals are widespread in Pleistocene sandy-argillaceous deposits of Belarus. The nearest Ordovician and Silurian exposures that could be considered as their source rocks are confined to the northern part of Estonia and several islands of the Baltic Sea. Some specimens in the collected material are represented by loose colonies preserved in fine detail. Being completely or mainly free of enclosing Paleozoic rock, they show almost no sign of chemical weathering or any visible damage caused during natural etching by acidic ground waters, which allows to eliminate acid dissolution as the mechanism of their natural separation from Paleozoic carbonate boulders. The specimens are very fragile and are characterized by negligible resistance to mechanical destruction. This does not support the hypothesis of glacial plucking and subsequent transportation of this material during advancement of Pleistocene Scandinavian glaciers widely accepted in most publications as the background hypothesis for explaining the delivery of boulders and pebbles into Pleistocene deposits. One should also take into consideration that in many published sources it is thought that glacial transportation was accompanied by the mechanical grinding of rock debris, which should demolish any fragile material by the mixture of boulder, pebble and gravel sediment. Instead, in the present paper the shore-fast ice delivery hypothesis is thought to be more consistently applied to the studied material. The shore-fast ice rafting hypothesis contradicts the glacial theory and has been proposed by some authors as one of the alternative explanations of erratic material delivery. According to direct observations on modern Arctic seashores, it involves an alternation of seasonal incorporation into ice of the near-surface bottom sediment and debris in the littoral zone and its subsequent transportation by floating ice. If this assumption is correct, loose fragile coral skeletons could be used for paleogeographic reconstructions as indicators of a probable Late Cenozoic Sea flooding area. [original abstract; Zaika]