Limestone Clasts Research Articles

Eocene carbonate clasts in Oligocene siliciclastic sediments of the Trapani Basin (NW Sicily): depositional and stratigraphic significance

The ‘Monte Bosco clays and quartz sandstones’, cropping out at Baglio Beatrice near Castellammare del Golfo (Sicily, southern Italy) and belonging to the Pre-Panormide domain, contain planktic and nannofossil assemblages indicating the lower Oligocene, whereas reworked larger foraminifers occurring in turbidites are upper Eocene, and limestone clasts scattered throughout the section and occurring in channelized conglomerates are lower Eocene (Cuisian) in age. The autochthonous benthic foraminiferal assemblages in the hemipelagic marly clay background sediment indicate a well-oxygenated sea floor and show a deepening-upward trend through the succession from a middle to lower bathyal zone. Turbidites are graded and the coarser fraction, at the base of the beds, is composed by scattered tests of shallow-water late Eocene foraminifers reworked into the Oligocene matrix dominated by planktic foraminifers. The latter dominate the finer fraction characterized by the occurrence of quartz grains. The analysis of six limestone clasts revealed the occurrence of four microfacies characterizing a shallow-marine moderate-energy environment, a high-energy vegetated shoal, a high-energy middle-ramp, and the outer-ramp. The investigated clasts are all of a similar age, middle Cuisian, according to the microfossils, which include alveolinids, ornatorotaliids, and Cuvillierina vallensis. The interpreted microfacies suggest a distally steepened ramp source area, although there is no outcrop of such a platform in NW Sicily. The ‘Monte Bosco clays and quartz sandstones’ were deposited along a slope periodically affected by turbidity currents and debris flows, which cannibalized cemented and unlithified Eocene shallow-water carbonate facies.

Latest Cambrian–earliest Ordovician conodonts and microbrachiopods from northern Victoria Land, Antarctica: Handler Ridge revisited

Conodonts and microbrachiopods of latest Cambrian–earliest Ordovician age are documented from the Handler Formation of northern Victoria Land, Antarctica. Five spot samples from allochthonous limestone clasts collected during expeditions conducted by the Korean Polar Research Institute in 2013–2014 yielded the conodonts Cordylodus proavus, C. lindstromi, Hirsutodontus simplex, and Teridontus nakamurai, associated with four species of brachiopods (two indeterminate acrotretides, a zhanatellid lingulide, and a siphonotretide tentatively referred to Schizambon reticulatus). The four conodont species are distinctive taxa occurring in the widely distributed Cordylodus lindstromi Biozone of the latest Cambrian and the Iapetognathus Biozone at the base of the Ordovician. The allochthonous limestone clasts in the Handler Formation were likely derived from now-lost carbonate shelves developed locally (in the Bowers Arc) or transported from further north. Fossil evidence from the Handler Formation indicates that the final episode of the Ross Orogeny that uplifted and deformed the Robertson Bay Group was no older than early Tremadocian (earliest Ordovician). Striking similarities in fossil content, ages and depositional settings between the limestone olistoliths in the Handler Formation and latest Cambrian–earliest Ordovician autochthonous and allochthonous carbonates of the post-Delamerian Orogen recognized in the Koonenberry Belt (Gnalta Shelf) in far western New South Wales support the depositional model considering the Robertson Bay Group as the synorogenic deposits of the Ross Orogeny.

Discovery of Upper Cretaceous Neo-Tethyan trench deposits in south Tibet (Luogangcuo Formation)

Sedimentary basins within the Transhimalayan arc-trench system provide paleotectonic and paleogeographic information on the evolution of the late Mesozoic–early Cenozoic Neo-Tethyan subduction zone along the southern Asian margin. This paper presents detailed stratigraphic, sedimentologic, petrographic, detrital-zircon geochronologic and Hf isotopic data from the Luogangcuo Formation exposed as part of the Xiukang Mélange in south Tibet. The Luogangcuo Formation was deposited (ca. 88–81 Ma) in a trench environment on a deep-sea fan fed from the Lhasa block through a submarine canyon. Dominant chert and subordinate sandstone and limestone clasts in conglomerate beds indicate recycling from the Neo-Tethyan subduction complex during repeated episodes of gravitational failure. The interbedded turbiditic sandstones were sourced directly from the Gangdese magmatic arc and central Lhasa terrane. Detrital volumes from the active Asian margin increased markedly at ca. 88 Ma as a result of uplift of central Lhasa, leading to deltaic progradation, filling of the Xigaze forearc basin, and bypassing of sediments funneled via canyons across the subduction complex to reach the Luogangcuo trench basin at abyssal depths.

Towards a revised stratigraphy for the Middle to Upper Palaeolithic boundary at La Güelga (Narciandi, Asturias, Spain). Soil micromorphology and new radiocarbon data

The archaeological sequence of the Palaeolithic site of La Güelga apparently shows an interstratification of Aurignacian between the Mousterian and Châtelperronian layers, a sequence which disagrees with the stratigraphic model for the Middle to Upper Palaeolithic transition in SW-Europe. We analyzed the witness section of the interior sector in archaeological zone D using micromorphology and collected new radiocarbon dates for the Aurignacian and presumably Châtelperronian levels in order to provide detailed sediment descriptions of the site and scrutinize the presumed interstratification. Thin sections from Mousterian levels 8 and 9 show microstratification, signs of trampling and preferential sub-horizontal orientation of elongated particles. These features are less strongly developed in the Aurignacian deposit of levels 5 and 6 and are lacking in the presumably Châtelperronian ones of levels 1 and 2. The deposits of the latter show other features of reworked slope deposits such as a randomized distribution of limestone clasts. Radiocarbon dating on bone samples from level 2 places this layer to between ~41.5 and 45 ka cal BP, hence older than Aurignacian level 5, dated to between ~35.5 and 41.5 ka cal BP. Comparative dating of bones with and without ultrafiltration pretreatment conducted in two different laboratories yielded results in excellent agreement. Overall, the micromorphological observations and new radiocarbon ages strongly suggest that the few finds of presumably Châtelperronian affinity and sediments of levels 1 and 2 were transported by slope processes into the shelter.

Lower Serpukhovian (Steshevian) foraminifers and algae from exotic limestone clasts of Nötsch (Eastern Alps, Austria)

The >1,000 m-thick Carboniferous sedimentary succession of Nötsch is divided into the Erlachgraben, Badstub, and Nötsch formations with poorly constrained precise ages, but probably constituting a continuous lithostratigraphic Group deposited from the latest Viséan to the early Bashkirian, thus including a complete Serpukhovian succession. We date the early Serpukhovian (Steshevian) in exotic limestone clasts of the Badstub Fm. based on algae and foraminifers. These limestone clasts have been reworked from a carbonate shelf, indicating that they are older than the Badstub Fm. Microfacies and fossil assemblages indicate that a shallow marine carbonate shelf was developed at the northern margin of the deep-sea basin of Nötsch. The assemblages include the red alga Hortonella, rare green algae, and incertae sedis algae Praedonezella, Aoujgalia, and Frustulata; howchiniid and lasiodiscid foraminifers; atypical endothyrids, probably belonging to Semiendothyra emend.; rare Janischewskina; taxonomically disputable eostaffellids (including Eostaffellina aff. paraprotvae) and pseudoendothyrids; attached forms transitional between pseudolituotubid Fusulinata and calcivertellid Miliolata; and probably the oldest known free Miliolata. Newly described taxa include the incertae sedis algae Praedonezella sebbarae nov. sp. and the foraminifers Pseudoendotaxis nov. gen., Quasilituotuba serpens nov. sp., Q. pseudospiroides nov. sp., and Eoglomospiroides carnica nov. sp. Revised foraminiferal taxa include Pseudolituotubidae, Quasilituotuba cf. serpuchoviensis nov. comb., and Q. ex gr. extensa nov. comb. The studied material provides information about the phylogeny of the first Miliolata and permits the reconstruction of the lineage of Pseudolituotubidae and Calcivertellidae, between the classes Fusulinata and Miliolata. The palaeobiogeography of Austria during the Serpukhovian is not yet clearly established, but relationships with the Saharan and Mediterranean Provinces exist, and especially with the Donbass. Fewer relationships are conspicuous with England, the Moscow Basin or the Urals.

Provenance and formation of the red palaeosol and lithified terra rossa-like infillings on the Island of Susak: A high-resolution and chronological approach

Red palaeosol (RP) covering the carbonate basement exposed at the bottom of the loess section and lithified terra rossa-like materials situated in cavities (LTR1) and karstified fissures (LTR2) in Cretaceous limestones were investigated by means of high-resolution approach, to give a systematic and deeper palaeopedological insight into reddish materials and the exposed red palaeosols on the island of Susak. Both, selected geochemical indicators of weathering (Al/Si, (Na + K)/Al and Fed/Fet) and provenance (La/Ce), as well as detailed mineralogical analysis clearly showed differences among LTR1, LTR2 and RP, respectively. LTR1 and LTR2 represent erosional remains of different soils that existed on the surface of the limestone bedrock prior to the formation of the RP. LTR2 has the highest ZTR (zircon-tourmaline-rutile index) index and contains bauxite minerals (gibbsite and boehmite), clays (kaolinite and mixed-layer clay minerals), and haematite. LTR2 bears characteristics of reworked bauxitic materials mixed with other soils that existed on the surface of the carbonate basement. Those materials might have been mixed and transported until they were captured in the karstified fissure, and, subsequently interlocked with calcite veins and lithified. This might have happened from the Eocene age on. Our attempt to resolve the age of LTR2 formation more precisely, using palaeomagnetic investigations, did not give unambiguous results because the extremely viscous behaviour of the LTR2 samples hinders the acquisition of a stable remanent magnetisation. If we exclude the secondary calcite, LTR1 bears typical mineralogical and geochemical characteristics (e.g. Fed/Fet ratio) similar to those of Istrian terra rossa. Insoluble residues of Cretaceous limestone might have been the main parent materials for the LTR1 formation while the most likely additional fluxes influencing terra rossa formation on the island of Susak were aeolian dust and flysch. The erosion remains ended in limestone cavities and were mixed with cm to dm sized angular and subangular limestone clasts and, subsequently, interlocked with calcite veins and lithified. The investigated RP profile comprised the following mineral horizons: Bwb1-Bwb2-Bwb3-R. The RP formed in a lithologically uniform material that dominantly presents a mixture of loess and, partly, remains of older soils (e.g. rounded clay coatings not related to macrovoids) that existed on the surface of the Cretaceous limestone. Fed/Fet ratio in RP reflects a low degree of weathering of Fe-containing primary silicates. Therefore, we can conclude that the RP does not fit a rather limited variation of selected Fe-oxide characteristics typical for terra rossa. The investigated RP was classified independently of the overlying material. The full name of the palaeosol that we classified is as follows: Hypereutric Chromic Cambisol (Episiltic, Endoloamic). Since no reversal of the EMF was recorded in the RP, we concluded that the RP formed during the Brunhes epoch. Luminescence dating was applied to establish the age of the RP. Based on the acquired data, we assume that the RP very likely formed during the Penultimate Interglacial (OIS7).

Lithostratigraphy and planktonic foraminifera of the uppermost Cretaceous-Upper Paleocene strata of the Tavas nappe of the Lycian nappes (SW Turkey)

The Lycian nappes lying on top of the para–autochthonous metamorphosed Menderes and unmetamorphosed Bey Daglari successions in SW Anatolia belong to the Tauride segment of the Anatolide–Tauride Block. The Tavas nappe is one of several nappe slices of the Lycian nappe sand forms structurally the lowermost tectono–stratigraphic unit. The upper part of the Tavas nappe succession is represented by planktonic foraminifera–bearing uppermost Cretaceous cherty micritic limestones and calciturbidites of the Babadag Formation and Lower Palaeogene micritic limestones and calciclastic rocks of the Faralya Formation in the study area. Lithostratigraphic characteristics and planktonic foraminiferal assemblages of the two formations in the Bozburun hill locality (S of Koycegiz) are documented for the first time in three stratigraphic sections in this study. The uppermost part of the Babadag Formation mainly comprises of alternating calciclastic and micritic limestones, which include diverse planktonic foraminiferal assemblages of mainly keeled morphotypes. The presence of Racemiguembelina fructicosa and Abathomphalus mayaroensis within the assemblages indicates a late Maastrichtian age for the uppermost part of the succession. Two sections of the overlying Faralya Formation comprise mainly planktonic foraminifera–bearing laminated micritic limestones, brecciated limestones and mudstones. Planktonic foraminiferal assemblages of the laminated micritic limestones are dominated by keeled Late Palaeocene morphotypes. The occurrence of Morozovella acuta and Globanomalina planoconica at the base of two sections suggests a Thanetian age for the deposits. The boundary between the Babadag and Faralya formations is characterized by a stratigraphic gap ranging from the latest Maastrichtian to the earliest Selandian. The gap was linked with the first of the three main events, when ophiolite obduction and incorporation of the Koycegiz Thrust Sheet into the Lycian allochthon occured. Cretaceous limestone clasts and foraminifers within the Thanetian calciclastic rocks of the Faralya Formation could be clues to that exposure anderosion.

Calpionellid zones of the Tithonian–Berriasian exotic limestone clasts from the Outer Carpathians, Poland

Calpionellids and chitinoidellids were identified from exotic limestone clasts occurring in flysch deposits of the Early Cretaceous to Oligocene age from the Silesian and Subsilesian nappes of the Polish Outer Carpathians. They represent the remnants of carbonate sedimentation along the northern and southern margin of the Severin-Moldavidic Basin, areas which are no longer preserved on the surface. Chitinoidellid and calpionellid assemblages characterize the Chitinoidella, Crassicollaria and Calpionella zones (latest early Tithonian–early Berriasian). The calpionellid zonation for the Western Carpathians was used for the present study, but some difficulties were encountered resulting from the application of this zonation. Cathodoluminescence imaging (CL) was useful for the identification of these microfossils in samples containing sparse and poorly preserved specimens, especially in the studied shallow-water limestone (the so-called Štramberk-type limestones).

Provenance of Holocene calcareous beach-dune sediments, Western Eyre Peninsula, Great Australian Bight, Australia

Much of western Eyre Peninsula adjacent to the Great Australian Bight is veneered with siliceous and calcareous Quaternary aeolian dunes. The lengthy coastline adjacent to this cool-water carbonate factory is a series of Precambrian crystalline bedrock-Pleistocene aeolianite headlands that separate many long, sweeping, Holocene carbonate sand beaches and their backbeach dunes. Incessant SW waves, rolling swells, and onshore winds have resulted in >350km of semi-continuous calcareous strandline aeolian sands. The sediment is composed of quartz grains, Cenozoic limestone clasts, and relict particles (extraclasts) but the deposits are overwhelmingly dominated by contemporaneous biofragments from offshore. These skeletal grains are, in order of relative abundance, molluscs>benthic foraminifers>coralline algae>bryozoans, and echinoids. Benthic foraminifers are mostly small (especially rotaliids and miliolids) but the large relict symbiont-bearing protistMarginopora vertebralis, which grew in the latter stages of MIS 2, is present locally. There are no significant onshore-offshore trends within individual beach-dune complexes. There is, however, a prominent spatial partitioning, with extraclast-rich sediments in the north and biofragment-rich deposits in the south. This areal trend is interpreted to result from more active seafloor carbonate production in the south, an area of conspicuous seasonal nutrient upwelling and profound nektic and benthic biological productivity. The overall system is strikingly similar to Holocene and Pleistocene aeolianites along the inboard margin of the Lacepede Shelf and Bonney Coast some 500km to the southeast, implying a potential universality to the nature of cool-water carbonate aeolianite deposition. The composition of these cool-water aeolianites is more multifaceted than those formed on warm-water, shallow flat-topped platforms, largely because of the comparatively deep, temperate shelf, the high-energy wave and swell climate impacting the shoreline, and thus the different geohistory during sea level change.

Paleoecology and paleoenvironments of Permian bivalves of the Serra Alta Formation, Brazil: Ordinary suspension feeders or Late Paleozoic Gondwana seep organisms?

This is the first record of a Permian seep deposit and an associated, morphologically bizarre, bivalve-dominated fauna from the Passa Dois Group, Paraná Basin, Brazil. Shales of the outer-shelf facies of the Serra Alta Formation preserve a low-diversity but high-abundant, large-sized bivalve fauna with unusual morphologies inside discoidal carbonate concretions. The bivalves are about ten times larger than tiny bivalves found scattered in laterally equivalent mudstones of the same unit. Intercalated between two concretion-bearing horizons, a cm-thick, sheet-like, disrupted, “brecciated”, partially silicified carbonate layer with microbially-induced lamination is recorded. In some areas, the carbonate layer shows vertical structures formed by injections of mud mixed with white limestone clasts and microbial linings. Immediately above this, silicified mudstones preserve small domal structures (= mounds) with a slightly depressed center. Monospecific concentrations of closed articulated shells of Tambaquyra camargoi occur at the base of these domes. Carbon-isotope (δ13C) values from the shells, “brecciated” carbonates, and fossil-rich concretions are all depleted (negative values ∼ −6.1 to −7.6‰). Combined taphonomic, sedimentological, petrographic, geochemical and paleontological data suggest that the disrupted, “brecciated” carbonate and associated fauna and domes may have formed by an exudation system. Indeed, this interval of the Serra Alta Formation is ∼8.7 m above the contact with the underlying, oil-rich Irati Formation. This unit has very high total organic carbon (up to 23%) values and high sulphur contents, supporting the interpretation of the lithological and paleontological features as result of seepage of organic compounds at the seafloor. Where the gases and hydrocarbons escaped, the seabed was colonized by, at least facultatively, chemosymbiotic bivalves. The species above belong to a highly endemic group of pachydomids that were shallow infaunal bivalves (SIB). Hence, they are not related to “classical” bivalves with extant representatives, which are chemosymbionts. This may reflect an extreme adaptive radiation and repopulation of anoxic-dysoxic bottoms of the Paraná Basin by SIB species.

Sloping fan travertine, Belen, New Mexico, USA

Pliocene to Quaternary age travertines are very well-exposed in quarries near Belen, New Mexico, U.S.A., on the western edge of the Rio Grande Rift system. A series of hillside springs produced travertine tongues tens of meters thick and hundreds of meters long. The accumulations represent deposits from individual springs as well as the amalgamation of deposits. The overall architecture is predominantly composed of sloping fans with a smaller component of terrace mounds. The sloping fan deposits commonly have a dip of <10°, however, they range from horizontal to near vertical. Individual strata display significant changes in depositional dip, beds pinch and swell, and some are completely truncated. Centimeter to meter scale terrace mounds exhibit the common stair-step morphology. As a consequence of vertical accretion in the pools, terrace mounds morphed into sloping fans. The travertine is composed of a variety of commonly reported constituents, i.e., centimeter thick laminae of bacterial shrubs and oncoids, foam rock, sheets and rafts, and finely crystalline crusts that occur throughout the sloping fan and terrace mound accumulations. Sheets and rafts formed as precipitates in pools on the surfaces of the fans and terraces as well as spelean deposits on the water surfaces of pools within cavities in the overall accumulation. Thus, the spelean rafts provide valuable indicators of original horizontality in the sloping fan strata. In addition, intraformational breccias, composed of locally torn-up travertine intraclastic boulders and deposited in with other travertine, and extraformational breccias, composed of torn-up travertine intraclasts mixed with siliciclastic fines and sand and Paleozoic limestone clasts transported downslope from higher on the hillside, are a common constituent in the sloping fan accumulation. The Belen travertines provide a very well-exposed example of sloping fan travertines and may provide relevant data with regard to the subsurface Aptian Pre-Salt deposits, offshore Brazil.

The Steepbank Formation: a paleokarst diamictite deposit in the Athabasca Oil Sands region of northeastern Alberta, Canada

Abstract The name “Steepbank Formation” is proposed for a paleokarst diamictite deposit that is present along the margins of the Middle Devonian Prairie Evaporite Formation in the Western Canada and Williston sedimentary basins, including the eastern portion of the Athabasca Oil Sands region. This poorly lithified diamictite forms a mappable unit that is distinct in both age and lithology from all contiguous formations. The Steepbank consists of clasts of dolostone, limestone, and siltstone up to the size of boulders with a matrix of silty to sandy calcareous mudstone. The material shows little or no evidence of bedding or sorting. Most clasts are angular and their orientation is commonly random. The diamictite formed in response to the dissolution of thick (up to 300 m) sequences of halite, anhydrite, and gypsum in the Prairie Evaporite Formation and the subsequent failure and collapse of interbedded and overlying insoluble strata. The top contact occurs where the intact strata of an overlying formation can be identified and is commonly gradational. The basal contact with the underlying Keg River Formation is sharp. Both contacts are unconformable. Evaporite dissolution and diamicton deposition likely began in late Middle Devonian time, moving down dip toward the west, and are continuing today near the Athabasca River.

Structural controls on carbonate-hosted Pb–Zn mineralization in the Dongmozhazhua deposit, central Tibet

Fault zones control the locations of many ore deposits, but the ore-forming processes in such fault zones are poorly understood. We have studied the deformation and ore textures associated with fault zones that controlled the lead–zinc mineralization of the Dongmozhazhua deposit, central Tibet, ∼100km southwest of Yushu City. Geological mapping shows that the structural framework of the Dongmozhazhua area is defined by NW–SE-trending reverse faults and superposed folds that indicate at least two stages of deformation. The first stage is characterized by tight nearly E–W-striking folds that formed during the closure of the Jinshajiang Paleo-Tethyan Ocean in the Triassic. The second stage of deformation produced NW–SE-trending reverse faults and related structures of the Fenghuoshan–Nangqian fold-and-thrust belt associated with India–Asia collision in the late Eocene to Oligocene. Scanline surveys along the ore-controlling fault zones show an internal structure that comprises a damage zone, a breccia zone with clasts that have become rounded, and a breccia zone with lenticular clasts, and this complex architecture was formed during at least two compressional substages of deformation. The Pb–Zn mineralization in the Dongmozhazhua area occurs exclusively close to NW–SE-trending reverse fault zones. Microtextural observations reveal that mineralization occurred as veinlets and disseminated blebs in limestone clasts, and as continuous bands and cements in fractured rocks. Cataclastic sulfide grains also can be seen in the matrix of some fault zones. The types of mineralization differ with structural position. The fillings of the ore-bearing veinlets typify the products of hydraulic fracture and both types of mineralization took place concurrently with regional contraction. We consider, therefore, that the ore-bearing fluids in the Dongmozhazhua deposit were concentrated in fault zones during regional compression and that the ore minerals were precipitated during hydraulic fracturing of host rocks. Subsequent fault activity pulverized some pre-existing sulfide material into cataclastic grains in the matrix of a tectonic breccia that developed in the same faults.

Quaternary aeolianites in south‐east Australia – a conceptual linkage between marine source and terrestrial deposition

AbstractCalcareous aeolianites are an integral part of many carbonate platforms and ramps. Such limestones are particularly common in heterozoan, Late Cenozoic carbonate systems, and it has been postulated that they could contain a particularly sensitive record of their offshore source. This hypothesis is tested herein by documenting and interpreting part of the most extensive and temporally longest such system in the modern world. The deposits are a combination of extraclasts and biofragments. Extraclasts are detrital quartz, relict allochems, older Pleistocene particles and Oligocene–Miocene limestone clasts. Biofragments are penecontemporaneous coralline algae, echinoderms, small benthic foraminifera, molluscs and bryozoans. The aeolianites differ in composition from distant, open shelf sediments because they contain more mollusc fragments and many fewer bryozoans. This difference is interpreted to be due to (i) most sediment was derived from near‐shore seagrass meadows and macroalgal reefs; (ii) all sediments were modified by hydrodynamics in near‐shore and beach environments; and (iii) fragments of infaunal, beach‐dwelling bivalves were added to the sediment at the strandline. Extraclasts should be expected in older Pleistocene and Cenozoic heterozoan deposits, because the limestones are poorly lithified, largely due to the lack of meteoric cementation, and so easily eroded. Thus, cool‐water aeolianites ought to contain more extraclasts than their warm‐water, tropical cousins. Seagrasses in temperate environments are more productive than in the tropics and thus potentially might contribute many more particles to the beach and dunes than do tropical systems. Although particle breakage in the surf zone cannot be proven, herein the abundance of whole benthic foraminifera and delicate bryozoans implies that suspension and flotsam shoreward transport was an essential process. The similarity of Pleistocene aeolianites over such a long time period herein suggests that the combination of postulated sedimentological, biogenic and hydrodynamic processes could be universally important.

Extreme block and boulder transport along a cliffed coastline (Calicoan Island, Philippines) during Super Typhoon Haiyan

This paper presents data and analysis for block and boulder transport during Super Typhoon Haiyan along a 4.5km long, low (5–12m) cliffed coastline in Calicoan Island, Eastern Samar, Philippines. Wave runup exceeding 15.2m elevation above mean sea level drove large limestone clasts, with volumes up to ~83m3, up to ~280m inland. A few very large clasts with volumes 65–132m3 were not transported by the waves. When combined with recent transport reported in May et al. (2015), Cox et al. (2016), and other literature, it is becoming increasingly clear that the largest blocks transported by storms overlie much of the tsunami transport range, increasing the difficulty in attributing the transport source without additional evidence. Comparison of present results with a global database of storm boulder transport shows a mass-elevation envelope outside of which no transport is observed.Initiation of motion criteria were extended to include non-rectangular cross-sections, which significantly reduces inferred velocities, particularly for overturning motion. These new relations were applied to the largest observed sliding and overturning boulders while considering coefficient uncertainties, and resulting velocity uncertainty was large enough that direct inference of wave heights would be problematic. Estimates of initiation velocities for cliff-edge boulders computed using lifting/joint-bounded relations were unreasonably large when compared to those for sliding and overturning boulders, suggesting that processes other than Bernoulli lift forces dominated at cliff edges.

Los depósitos clásticos pos-Laramide de la Sierra de Guanajuato: Implicaciones de su composición en la evolución tectono-sedimentaria y paleogeográfica

Este artículo presenta los resultados del estudio sobre la sedimentación, los ambientes sedimentarios, la evolución tectono-sedimentaria y paleogeográfica de los depósitos clásticos pos-Laramide y pre-vulcanismo de la Sierra Madre Occidental en la Sierra de Guanajuato. Los depósitos clásticos rojos analizados corresponden al Conglomerado Guanajuato y al Conglomerado Duarte del Eoceno que fueron depositados en la parte media y distal de abanicos aluviales. Los depósitos estudiados están constituidos de clastos de calizas, granito, andesita, rocas sedimentarias, diorita y piroxenita, que indican la erosión de bloques levantados del complejo basal de la Sierra de Guanajuato (Terreno Guerrero). El análisis composicional y petrográfico de clastos de calizas permitió reconocer calizas de cuenca y calizas de plataforma somera provenientes del complejo basal de la Sierra de Guanajuato (Cuenca Arperos). Las calizas de plataforma somera presentan fragmentos esqueletales de bivalvos, braquiópodos, gasterópodos, equinodermos y foraminíferos bentónicos del Berriasiano-Valanginiano. Los clastos de caliza de plataforma se interpreta que podrían proceder de facies someras limítrofes de la cuenca Arperos, cuyos afloramientos originales actualmente no afloran en la Sierra de Guanajuato.

Geological significance of the discovery of Middle Triassic (Ladinian) radiolarians from the Hong Hoi Formation of the Lampang Group, Sukhothai Zone, northern Thailand

This paper presents a newly found fauna of Ladinian (Middle Triassic) radiolarians from the Hong Hoi Formation of the Lampang Group, Sukhothai Zone, northern Thailand. The Ladinian age determined by the radiolarian fauna concords with the age previously determined by mollusks. The study section consists of intercalated sandstone and shale in the lower part and a thick conglomerate in the upper part. The radiolarian-bearing siliceous beds are intercalated within the lower unit. The lithic sandstone of the lower unit consists mainly of volcanic rock fragments, quartz, and feldspar, whereas the thickly bedded conglomerate of the upper unit is characterized by abundant gravel-sized clasts of volcanic rock and limestone. These lithic features of the study section suggest that during deposition the Hong Hoi Formation was located near a supply of volcanic materials. A forearc basin close to the Sukhothai Arc would be the most suitable environment for the deposition. The Ladinian age determined by the radiolarian fauna supports the occurrence of intensive volcanic activity within the Sukhothai Arc during the Middle Triassic.

Tectono-stratigraphic reconstruction of the Keban metamorphites based on new fossil findings, Eastern Turkey

Keban metamorphites located at the orogenic belt of the Eastern Taurides is an allochtonous union metamorphized at the greenschist facies comprised of several nappes. Contrary to the massives around it, the aging of the union is not quite satisfactory due to the lack of fossil data. Permo-Triassic/Permo-Carboniferous ages have been used until now for the age of the metamorphites that are stated to be located only at a single location, the species of which have not been determined and which are based on two fossil data. However, for the first time in this study, “microgastropods” have been found at Early Triassic age related with The Great Dying at the end of the Permian inside the clastic limestones at the base levels of the Nimri Formation which is one of the lower nappes of the Keban metamorphites. Again, trace fossils Planolites, Rhizocorallium, Thalassinoides, Helminthopsis and (?)Protovirgularia have been determined for the first time in the layered crystallized limestones at the medium levels of the Nimri Formation. This ichnofabric is frequently observed in the Middle Triassic aged limestones at Germany, Poland, Austria, Italy and the Taurides and is known as the “vermicular limestone facies”. The ages of Keban marble, Delimehmet and Süleymanlı Formations, tectonically located on the Nimri Formation, are evaluated by regional correlations as Middle-Late Devonian, Late Devonian and Early Carboniferous, respectively. In addition, probably pre-Triassic aged, dark green colored metadiabase dykes have been inserted in the Delimehmet formation in relation with the Variscan Orogeny. Regional correlations with other units and massives indicate that the Keban metamorphites that have deposited at the farthest north of the south branch of the Neo-Tethys ocean paleogeographically may be the continuation of the Bolkardağı Union at the east rather than the Alanya and Geyikdağı Unions.

Stratigraphy and conodont and ammonoid ages of Upper Triassic Nakijin Formation in Hedomisaki area, Okinawa-jima, Japan

We present a lithostratigraphic, biostratigraphic (conodont and ammonoid), and petrographic study of Upper Triassic bedded limestones (Nakijin Formation) from Hedomisaki, northern Okinawa Island, Japan. The Hedomisaki limestones comprise two formations: Upper Triassic bedded limestone of the Nakijin Formation and massive limestone of the Hedomisaki Formation of unknown age. The Nakijin Formation is divided into three members: (1) lower = dark gray micritic limestone (ca. 110 m thick); (2) middle = clastic limestone (ca. 180 m thick); and (3) upper = clastic limestone with slump beds (ca. 110 m thick). Biostratigraphic datums based on conodont and ammonoid fossils show that the Nakijin Formation was deposited in the early Carnian through the middle Norian. Microfacies in the Nakijin Formation are classified into four major facies: (1) radiolarian limestone–mudstone; (2) thin-shelled bivalve mudstone–wackestone; (3) litho–bioclastic packstone; and (4) peloidal–bioclastic packstone. Facies 1 and 2 are dominated by planktonic biota, indicating a deep-water pelagic environment. The clastic limestones (3, 4) in the middle to upper member of the Nakijin Formation were likely deposited in a shallow-water environment on and around an oceanic seamount in an open ocean setting.

Conodonts and tabulate corals from the Upper Ordovician Angullong Formation of central New South Wales, Australia

Zhen, Y.Y., Wang, G.X. & Percival, I.G., August 2016. Conodonts and tabulate corals from the Upper Ordovician Angullong Formation of central New South Wales, Australia. Alcheringa 41, xxx–xxx. ISSN 0311-5518.The Angullong Formation is the youngest Ordovician unit exposed in the Cliefden Caves area of central New South Wales. Its maximum age is constrained by a Styracograptus uncinatus graptolite Biozone fauna at the very top of the underlying Malongulli Formation, but the few fossils previously reported from higher in the Angullong Formation are either long-ranging or poorly known. From allochthonous limestone clasts in the middle part of the formation, we document a conodont fauna comprising Aphelognathus grandis, A. solidum, Aphelognathus sp., Aphelognathus? sp., Belodina confluens, Drepanoistodus suberectus, Panderodus gracilis, Panderodus sp., Phragmodus undatus, Pseudobelodina inclinata and Pseudobelodina? sp. aff. P. obtusa, which supports correlation with the Aphelognathus grandis Biozone (late Katian) of the North American Midcontinent succession. The species concepts of Aphelognathus and Pseudobelodina are reviewed in detail. Associated corals are exclusively tabulates, dominated by agetolitids, including Agetolites angullongensis sp. nov., Heliolites orientalis, Hemiagetolites breviseptatus, Hemiagetolites sp. cf. H. spinimarginatus, Navoites sp. cf. N. circumflexa, Plasmoporella bacilliforma, P. marginata, Quepora sp. cf. Q. calamus and Sarcinula sp. Affinities of the coral fauna from the Angullong Formation are closer to faunas from northern NSW and northern Queensland than to the locally recognized Fauna III of late Eastonian age in central NSW. We propose a subdivision of Fauna III to account for this difference, with the late Katian Fauna IIIB characterized by the incoming of agetolitid corals. The currently known distribution of representatives of this group with adequate age constraints suggests that agetolitids possibly originated in North China, subsequently migrating to Tarim, South China and adjacent peri-Gondwanan terranes while also spreading eastward to northern Gondwana, where they progressively moved through eastern Australia to reach the central NSW region by the early Bolindian.Yong Yi Zhen* (yong-yi.zhen@industry.nsw.gov.au) and Ian G. Percival (ian.percival@industry.nsw.gov.au), Geological Survey of New South Wales, W.B. Clarke Geoscience Centre, 947–953 Londonderry Road, Londonderry, NSW 2753, Australia; Guangxu Wang (gxwang@nigpas.ac.cn), State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, 39 East Beijing Road Nanjing 210008 PR China.