Fossil Content Research Articles

Anatomy of a mixed bioclastic–siliciclastic regressive tidal sand ridge: Facies‐based case study from the lower Pleistocene Siderno Strait, southern Italy

AbstractSand ridges, a common feature of modern open shelves, reflect persistent currents and sediment availability under recent transgressive conditions. They represent the largest bedforms in the oceans and, as such, can yield information on long‐term oceanographic processes. However, there is a limited number of tidal sand ridges documented from the rock record, examples of regressive tidal sand ridges are scarce and studies describing ridges in straits are even more rare. This study analyses a Gelasian succession within a structurally controlled, tide‐dominated strait in the Siderno Basin, southern Italy. The strait connected two wider basins, and accumulated sediments reworked by amplified tidal (bi‐directional) currents. A series of tidal sand ridges with superimposed dunes developed close to the south‐eastern end of the strait, where bathymetry was deeper and flow expansion occurred. One of the best‐exposed tidal sand ridges, 65 m thick, crops out along a ca 2 km long cliff. Large‐scale, ESE‐prograding, seaward‐offlapping shingles contain sets of bioclastic–siliciclastic, coarse‐grained, cross‐stratified sandstones, erosionally overlying upper Pliocene shelf marls and fine‐grained sandstones. Cross‐strata show angular, tangential and sigmoidal foresets with compound architectures and a SSE migration, i.e. oblique to the main growth direction. Fossil content indicates open‐marine conditions. The succession changes abruptly across an erosion surface to non‐tidal, highly burrowed mixed siliciclastic–bioclastic fine‐grained sandstones, less than 15 m thick. Documented features reflect stages of nucleation, active accretion and abandonment of an individual sand ridge, during a complete cycle of relative sea‐level change. The ridge formed during a phase of normal regression, with accretion occurring during an initial highstand and the ensuing falling stage. During the lowstand the ridge was split into several minor bodies by enhanced tidal currents. The ensuing transgression draped the moribund ridge with tabular strata, whereas final highstand shelf sedimentation reworked the top of the underlying sand body with weak currents.

A tectonic carpet of Variscan flysch at the base of a rootless accretionary prism in northwestern Iberia: U–Pb zircon age constrains from sediments and volcanic olistoliths

Abstract. The allochthonous complexes of Galicia–Trás-os-Montes Zone (NW Iberia) are part of a rootless tectonic stack which preserves part of a Variscan accretionary prism. They are formed by individual tectonic slices marked by specific tectonometamorphic evolutions, which were piled up in a piggy-back mode onto its relative autochthon, the Central Iberian Zone (CIZ). Allochthony decreases from the structurally upper thrust sheets towards the lower ones. The lowermost unit of the stack is known as the Parautochthon or Schistose Domain. It is characterized by a low metamorphic grade in contrast with higher temperatures and/or pressures estimated for the overlying allochthonous units and shares the stratigraphic sequence with the underlying autochthon. The Parautochthon is divided in two structural and stratigraphic sub-units: (i) the Lower Parautochthon (LPa) is made of synorogenic flysch-type sediments with varied turbiditic units and olistostrome bodies, showing Upper Devonian–lower Carboniferous age according to the youngest zircon populations and fossiliferous content; (ii) the Upper Parautochthon (UPa) is composed of highly deformed preorogenic upper Cambrian–Silurian volcano-sedimentary sequence comparable with the nearby autochthon and to some extent, also with the high-P and low-T Lower Allochthon laying structurally above. The UPa was emplaced onto the LPa along the Main-Trás-os-Montes Thrust, and the LPa became detached from the CIZ relative autochthon by a regional-scale structure, the Basal Lower Parautochthon Detachment, which follows a weak horizon of Silurian carbonaceous slates. A review on the detrital zircon studies on the synorogenic LPa complemented by zircon dating of 17 new samples is presented here. The results support the extension of the LPa underneath the NW Iberian allochthonous complexes, from Cabo Ortegal, to Bragança and Morais massifs. Its current exposure follows the lowermost tectonic boundary between the Galicia–Trás-os-Montes (allochthon) and Central Iberian (autochthon) zones. The youngest zircon age populations point to a maximum sedimentation age for the LPa formations ranging from Famennian to Serpukhovian and supports the piggy-back mode of emplacement of the Galicia–Trás-os-Montes Zone, of which it represents the latest imbricate. The zircon age populations in the LPa allow the sedimentary provenance areas to be constrained, showing the intervention of nearby sources (mostly the UPa) and/or multiply recycled and long-transport sediments with a typically north-central Gondwana age fingerprint, also found in the Lower Allochthon, UPa and Autochthon. Complementary geochronology of volcanic olistoliths trapped in the LPa sediments and of late Cambrian to Upper Ordovician rhyolites from the UPa is also presented. It shows a direct relationship between the major blocks source area (UPa) and the setting place (LPa). Old zircon age patterns show that the LPa sedimentary rocks were recycled from detrital rocks of the allochthon (advancing wedge) and the nearby autochthon (peripheral bulge).

Annually resolved sediments in the classic Clarkia lacustrine deposits (Idaho, USA) during the middle Miocene Climate Optimum

The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is closely associated with Columbia River Basalt Group volcanism. The flood basalt dammed a local drainage system to form the paleolake, which preserved a plant fossil Lagerstätte in its deposits. However, the precise age and temporal duration of the lake remain unsettled. We present the first unequivocal U-Pb zircon ages from interbedded volcanic ashes at the P-33 type location, constraining the deposition to 15.78 ± 0.039 Ma. Using micro–X-ray fluorescence and petrographic and spectral analyses, we establish the annual characteristics of laminations throughout the stratigraphic profile using the distribution of elemental ratios, mineral assemblages, and grain-size structures, as well as organic and fossil contents. Consequently, the ~7.5-m-thick varved deposit at the type location P-33 represents ~840 yr of deposition, coincident with the end of the main phase of Columbia River Basalt Group eruptions during the Miocene Climate Optimum. The timing and temporal resolution of the deposit offer a unique opportunity to study climate change in unprecedented detail during global warming associated with carbon-cycle perturbations.

A survey of the paleontological heritage of Paraná State, Brazil

The state of Parana has a considerable area with sedimentary outcrop rocks from the Parana Sedimentary Basins (Paleozoic and Mesozoic) and Bauru (Mesozoic), Curitiba Basin (Cenozoic), and metasedimentary basement rocks (Proterozoic) with fossiliferous content. The state’s paleofauna and paleoflora, geologically distributed over more than one billion years, are diversified and acknowledged in several scientific publications. On this regard, a survey of the main collections and paleontological sites in Parana state (Table 1) was conducted to provide a basis for the conception of a geoscience museum and with the scope of presenting representative fossils of the geological history of this region. The methodological procedures consisted of literature search, consultations with paleontologists, visits to various state institutions and a selection of the samples in different sectors of the State University of Ponta Grossa (UEPG). The surveyed set of paleontological collections and sites indicate the heritage that is known by the state research institutions and museums and allowed to organize and quantify the set of fossils that comprise the collection of the UEPG’s Museum of Natural Sciences, which now exhibits to the public the evolutionary history of Parana’s fossils. The survey identified 25 geosites in the state and 10 museological institutions located in 20 municipalities, which represent the most valuable scientific and educational paleontological heritage, as emphasized in this text.

Microfacies Characterizations and Paleoenvironment of Upper Part of Qamchuqa Formation from Chwarqauran Section, Sulaimaniyia Area, Kurdistan Region, Iraq

The Qamchuqa Formation was studied in Chwarqauran section, Sulaimanyia, Kurdistan region, Northeastern Iraq. The lithology of the formation contains limestone throughout the whole section except for one bed of dolomite at the Middle part. Twenty-four slides were prepared from 24 rock samples that were taken from this section to discriminate the petrography and fossil content. The petrographic study shows four main microfacies including lime mudstone, wackestone, packstone, and floatstone. Additionally, there are four sub microfacies: bioclast wackestone, miliolid wackestone, bioclast packstone and orbitolinid packstone. However, the fossil content shows the abundance of benthic foraminifera against the planktonic. All the microfacies indicate facies zone 7, 8 and 9A which reflect deposition in the platform interior between the tidal flat to the mid ramp and back reef environment

Paleoenvironmental and paleoclimatic reconstruction of Lower to Upper Cretaceous sequences of the Bauru Basin based on paleosol geochemistry and mineralogical analyses

The Cretaceous climate was characterized by arid and semiarid conditions in different parts of the world. Climatic changes for the Early to Late Cretaceous had been reported by many authors in North America, East Asia, Africa, and South America due to the geological evolution of Laurasia and Gondwana. In South America, the Bauru Basin, located in Brazil, is one of the most critical places to develop paleoclimatic reconstructions due to the presence of well-preserved Cretaceous sedimentary sequences, as well as abundant fossil content and paleosol profiles. The transition between the Lower and Upper Cretaceous in the Bauru Basin is represented by the Santo Anastácio and Araçatuba formations, which are characterized by a succession of sandstones, claystones, and paleosols. The paleosols are well distributed in the basin, providing valuable information about the paleoenvironmental conditions and insights about the tectonic and climatic changes in the Cretaceous Period. Since the 1960's decade, the Cretaceous paleosols of the Bauru Basin have been used as stratigraphic and sedimentological proxies providing paleoenvironmental and paleoclimatic insights, principally for the Late Cretaceous Period. This study, based on macromorphological descriptions, clay mineralogy (X-ray diffraction and scanning electron microscopy - SEM), and geochemical of paleosols, identified environmental and climatic patterns from the Lower and Upper Cretaceous. Results allowed to elaborate maps of paleoclimatic evolution that indicate changes occurred from Lower to Upper Cretaceous sequences of the Bauru Basin. These changes were compared and correlated with other continental basins in West Gondwana and Laurasia around the world, contributing to the understanding of the Cretaceous paleoclimatic context of South America.

The tetrapod fauna of the upper Permian Naobaogou Formation of China: 6. Turfanodon jiufengensis sp. nov. (Dicynodontia).

The dicynodont fossils from the Naobaogou Formation of Nei Mongol, China are abundant and diverse but poorly studied. In this article, one nearly complete skeleton and four cranial specimens from the Naobaogou Formation are referred to the dicynodontoid genus Turfanodon as a new species, T. jiufengensis. Previously, Turfanodon was known only from upper Permian sites in Xinjiang and Gansu. The new specimens are referred to Turfanodon based on the following characters: snout tall with steeply sloping profile, anterior tip of the snout squared off, facial region heavily pitted, nasal bosses present as paired swellings near the posterodorsal margin of the external nares, preparietal depressed, intertemporal bar long and narrow, premaxilla contacting frontal, palatal surface of premaxilla exposed in lateral view, and anterior pterygoid keel restricted to the anterior tip of the anterior ramus of the pterygoid. Turfanodon jiufengensis is differentiated from the type species, T. bogdaensis, by a contact of the lacrimal with the septomaxilla, discrete, raised nasal bosses, the dorsal edge of the erupted portion of the canine tusk slightly posterior to the anterior orbital margin, an anterior extension of the lacrimal distinctly shorter than that of the prefrontal, and a premaxillary dorsal surface with a median ridge. The holotype skeleton of T. jiufengensis includes a complete axial column with 50 vertebrae (six cervical, 23 dorsal, six sacral, and 15 caudal). Turfanodon represents the first confirmed tetrapod genus shared by the late Permian faunas of the Junggar and Ordos basins, and appears to be the first dicynodont genus distributed across both tropical and temperate zones (based on paleoclimate reconstructions). Based on tetrapod fossil content, the Naobaogou Formation can be roughly correlated to the Daptocephalus Assemblage Zone of South Africa (255–252 Ma in age).

Late Cretaceous Bauru Group biota from Southern Goiás state, Brazil: history and fossil content

The southern Goiás state region of Central Brazil has an extensive and informative record of fossil biota. Particularly over the last five years, there has been a great increase in fossil finds, which has enabled a greater understanding of this region's fauna and flora during the Late Cretaceous. In this article, we provide an updated synthesis of the biota from the Cretaceous of the southern Goiás state, the record of plants, gastropods, turtles, crocodilians, titanosaurs, and theropod dinosaurs.

Bioerosional structures from the Late Pleistocene coral reef, Red Sea coast, northwest Saudi Arabia

Herein, 20 ichnospecies belonging to 8 ichnogenera were identified in bivalves, gastropods, and corals (n = 701) from the Late Pleistocene coral reef along the Red Sea coast, northwest Saudi Arabia. The trace fossils were produced by clionid sponges (47.39%), endolithic bivalves (42.17%), polychaete annelids (5.42%), vermetid gastropods (3.81%), and acrothoracican barnacles (1.21%). The recognized ichnotaxa were Entobia geometrica, E. ovula, E. cf. goniodes, E. cf. retiformis, E. cretacea, Entobia isp., Gastrochaenolites torpedo, G. lapidicus, G. cf. dijugus, Gastrochaenolites isp., Oichnus paraboloides, O. simplex, Oichnus isp., Caulostrepsis taeniola, Caulostrepsis isp., Maeandropolydora cf. sulcans, Maeandropolydora isp., Renichnus isp., Centrichnus isp., and cf. Rogerella isp., Most bivalves and gastropods contain Entobia rather than Gastrochaenolites, which is commonly found in the larger and thicker corals. The content of the trace fossils indicated an Entobia ichnofacies formed in the coral reef during transgression. The habitat conditions changed gradually, from well-oxygenated, shallow, high-energy back-reef and reef crest bioeroding polychaetes and bivalves, to deep, low-energy reef slope dominated by boring sponges.

Assessing the lithological composition of carbonate rocks of the Permian age in order to clarify calculated parameters

The article deals with the determination of the reservoir properties of Permian-age carbonate rocks. There is a section dissection technique, taking into account the fossil organisms prevailing for a particular geological age. It was noted a high content of silica in the lower Artinskian deposits of Toravey and Varandey fields of the Komi Republic. The presence of silicon is associated with an increase in the population of siliceous sponges during this period of sedimentation; this fact caused the maximum values of porosity and permeability in the corresponding intervals. However, this was also the reason for the high values of the residual water saturation factor and, as a result, low oil flow rates from the lower Artinskian stage. The need for detailed correlation and accounting for the content of fossils in the rocks when dissecting the well section made it necessary to systematize the available actual material on core and well testing. It became obvious that the separation of reservoirs and stages at the qualitative level isn't possible, so quantitative estimates of the parameters that are significantly different for the upper and lower Artinskian deposits and allow you to dissect the well section were proposed.

Provenance of metasedimentary rocks of the western Dom Feliciano Belt in Uruguay: Insights from U–Pb detrital zircon geochronology, Hf and Nd model ages, and geochemical data

New isotopic and geochemical data for the Paleo- Meso- and Neoproterozoic metasedimentary cover of the southern Dom Feliciano Belt (Brasiliano/Pan-African) are presented and evaluated combined with published information. Whole-rock major and trace element geochemistry indicates that the dominant source for all the units had a composition similar to average upper continental crust. The geochemistry is similar even for late Ediacaran successions with a source component from slightly older Ediacaran granites, due to the crustal origin of these granites. Age constraints based on detrital zircon, fossil content, interbedded volcanic rocks and isotope geochemistry confirm Paleo-, Meso-, and Neoproterozoic successions, despite uncertainties remain in some cases. Detrital zircon data show the dominance of Archean (3.3–2.8 Ga) to Paleoproterozoic (2.2–1.9 Ga), and subordinated Mesoproterozoic (1.5–1.3 and 1.1 Ga) and Neoproterozoic (0.5–0.6 Ga) ages. Lu–Hf zircon and Sm–Nd whole-rock model ages confirm that the Archean and the Paleoproterozoic were the major crustal growth periods for the source areas. U–Pb detrital zircon age distributions and model ages demonstrate that the Nico Pérez Terrane and not the Río de la Plata Craton was the source for most metasedimentary rocks of the western Dom Feliciano Belt. Likewise, comparison of Archean, Paleo-, Meso- and Neoproterozoic events supports that the Nico Pérez Terrane could represent a fragment of the Congo Craton.

The carbonate platform of the Upper Tibasosa Formation, Lower Cretaceous, Eastern Cordillera Basin, Firavitoba-Boyacá, Colombia

The Tibasosa Formation is the main source of limestones in Boyacá. This unit corresponds to a Valanginian-Albian age according to the fossil content in the Eastern Cordillera Basin, recording the first incursion of the Cretaceous sea in Firavitoba. Outcrop-based facies and stratigraphic analyzes of the ~12 m-thick siliciclastic-carbonate succession of the uppermost Tibasosa Formation indicate tidal and carbonate systems. Ten facies/microfacies are grouped into two facies associations (FAs): FA1, tidal flat deposits consist of laminated sandstones/siltstones and floatstones with a single organism dominance (bivalve shells); and FA2 comprises fossiliferous rudstones, floatstones, packstones, and wackstones, representing a carbonate platform. The petrographic description determined rock textures/genesis and the diagenetic sequence with features of the eodiagenesis, mesodiagenesis, and telodiagenesis suggesting a primary origin of these carbonates. The analysis using cathodoluminescence (CL), energy disperse spectrometry (EDS), and scanning electron microscopy (SEM) allowed identify compositional differences, cementation phases, and morphological features in different processes as micritization, neomorphism, porosity, pyritization, compaction, cementation, fracturing, and weathering. The interpretation of facies and microfacies indicated a deposition mainly in a shallow platform with variation in the hydraulic conditions, warm waters, and episodic events of storms/tsunamis that fragmented the bioclasts. A shallow marine system in the Eastern Cordillera Basin during Cretaceous indicates a large transgressive event that flooded hundreds of kilometers, being a link with the Pacific Ocean before the Andes uplift. The main diagenetic events correspond to micritization, cementation of calcite, and mechanical/chemical compaction as a result of microbial activity, dissolution, precipitation in the vadose/phreatic zone, and burial diagenesis. The diagenetic sequence events reveal the incidence of marine and meteoric process that reduced porosity and attest to the microbial activity in carbonate precipitated. This new interpretation allows the understanding of carbonate platforms in the Eastern Cordillera Basin for future correlations of the Cretaceous sea in Colombia.

Abordagem didática do tema Paleontologia em uma escola de ensino fundamental da rede pública em Ponta Grossa, PR

Paleontology is a fundamental theme for the study and understanding of the origin and evolution of life on earth and is included in documents that govern basic education in Brazilian schools. The city of Ponta Grossa is widely known for its sites with abundant fossiliferous content. Based on the relevance of the theme and the characteristics of the region, this study evaluated the level of knowledge about Paleontology and the preservation of Paleontological Heritage among elementary school students of a public school. We used questionnaires, lectures, exhibitions of fossils from the region, and analysis of the textbooks used by the school with two classes of 7th and 8th grade. In general, the students of the four classes demonstrated a similar level of initial knowledge about the theme, presenting basic conceptualization difficulties and a lack of knowledge about the occurrence of fossils in the region. A lack of approach to the theme in the analyzed textbooks was also verified, which corroborates the low level of knowledge of the students. The activities applied were effective in the appropriation of knowledge, with changes in the level of understanding of the students at the end. The importance of using different methodologies for teaching this science is emphasized.

New leaf species from the upper Miocene flora of the leaf-bearing Wischgrund clay (Lower Lusatia, Brandenburg, Germany)

This is a brief outline of the fossil content of the Wischgrund leaf-bearing clay (Lower Lusatia, Brandenburg State, Germany), which belongs to the youngest Neogene layers of Lower Lusatia (upper Miocene, Tortonian). It is a deciduous temperate flora, with a small proportion of evergreen species. The reconstructed vegetation can be assigned to an azonal swamp forest with Taxodium and a riparian forest with Liquidambar and Acer as the most frequent species. Furthermore, a zonal Mixed Mesophytic Forest characterized by Quercus and Fagus is proposed in upland positions. The flora consists of 78 species of leaves, 51 carpological species and 82 palynological groups. The climate belongs to Cfa-type according to Köppen. Two new species of leaves are described from there, Pyracantha pseudococcinea sp. nov. and Ternstroemites klettwitzensis sp. nov.

Interevaporitic deposits of Las Minas Gypsum Unit: A record of Late Tortonian marine incursions and dolomite precipitation in Las Minas Basin (eastern Betic Cordillera, SE Spain)

The Las Minas Gypsum Unit consists of more than 100 m of alternations of gypsum, carbonates and marls in Las Minas Basin (Betic Cordillera). Although this unit has been previously described as lacustrine, a marine influence in the basin has been suggested. This study provides new geochemical and paleontological data supporting the marine influence during the interevaporitic episodes, allowing to refine the palaeogeography of the eastern Betic Seaway during the Late Tortonian.87Sr/86Sr ratios in gypsum (0.70797 to 0.70825) suggest recycling of Triassic evaporites. The sulphate isotopic values in gypsum (11.5 < δ34SVCDT < 21.9‰; 16.6 < δ18OVSMOW < 28.1‰) are indicative of microbial sulfate-reduction activity. Carbonates are mainly composed of dolomite formed by subspherical crystal aggregates related to bio-mediated processes. The 87Sr/86Sr values in the interevaporitic carbonates (0.70823 to 0.70851) are higher than those expected for Triassic marine authigenic carbonates but lower than expected for the Late Miocene ones, suggesting a mixing of continental and marine water contributions. The ‘non-marine’ isotopic values in gypsum and carbonates contrast with an abundant content of marine siliceous fossils (radiolarians, diatoms, porifera, etc.) in the marls and carbonates that reveals marine incursions into the basin between periods of gypsum precipitation. A tephra layer identified in Las Minas and in the nearby El Cenajo Basin, located in a more inland position, allows a precise correlation between both basins, showing marine fossils in Las Minas and lacustrine in El Cenajo. In El Cenajo Basin, marine microfossils have been found but only in some levels, while others show lacustrine diatoms. A new palaeogeographic model of evaporitic lakes with temporal marine connections is proposed for the latest Tortonian in this region, when the uplift of the Betic Cordillera was very active accelerating the palaeogeographic evolution.

Holocene progradation and retrogradation of the Central Texas Coast regulated by alongshore and cross‐shore sediment flux variability

AbstractFifteen transects of sediment cores located off the central Texas coast between Matagorda Peninsula and North Padre Island were investigated to examine the offshore record of Holocene evolution of the central Texas coast. The transects extend from near the modern shoreline to beyond the toe of the shoreface. Lithology, grain size and fossil content were used to identify upper shoreface, lower shoreface, ebb‐tidal delta and marine mud lithofacies. Interpretations of these core transects show a general stratigraphic pattern across the study area that indicates three major episodes of shoreface displacement. First, there was an episode of shoreface progradation that extended up to 5 km seaward. Second, an episode of landward shoreline displacement is indicated by 3–4 km of marine mud onlap. Third, the marine muds are overlain by shoreface sands, which indicates another episode of shoreface progradation of up to 5 km seaward. Radiocarbon ages constrain the onset of the first episode of progradation to ca 6.5 ka, ending at ca 5.0 ka when the rate of sea‐level rise slowed from an average rate of 1.6–0.5 mm/yr. Results from sediment budget calculations and sediment transport modelling based on reasonable estimates of an ancient shoreline shape and wave climate indicate that the first progradation was a result of sand supplied from erosion of the offshore Colorado and Rio Grande deltas. The transgressive phase occurred between ca 4.9 ka and ca 1.6 ka and coincided with a major expansion of the Texas Mud Blanket, which resulted in burial of offshore sand sources and the shoreface being inundated with mud. The second, more recent episode of shoreface progradation began ca 500 years ago with a maximum rate of ca 6 m/yr. This most recent change signals a healing phase of coastal evolution from the late Holocene transgressive event. Currently, the shoreline along the central Texas coast is retreating landward at an average rate of 0.30 m/yr, indicating that the second progradation event has ended.

LARGE FORAMINIFERA FROM LIMESTONE IN THE RAJAMANDALA FORMATION, SUKABUMI, WEST JAVA

Rajamandala Formation is a limestone reef formation that is exposed in the Rajamandala – Sukabumi area, West Java. Different from those in the Rajamandala area, this formation which is located in the Sukabumi area is still rarely analyzed, especially from its large foraminifera. This study aims to assess the content, age, and depositional environment of reef limestone from the Rajamandala Formation based on large foraminifera. Research method was carried out in several stages. Sampling was done by spot sampling as many as 6 samples. Then, thin section observations was carried out using Olympus CX-22 binocular microscope. Finally, age and environmental analysis were carried out using basic biostratigraphic methods and cluster analysis based on the fossil content of large foraminifera. Result, the limestone reefs of Rajamandala Formation in Sukabumi area have varied material content. These rock ages were found to be in the Late Oligocene range (Chattian). This rock depositional environment is in shallow marine environment which is divided into 3 main clusters. The first cluster is dominated by Austrotrilina and Borelis which shows the Backreef shelf environment. The second cluster is dominated by Heterostegina and Cycloclypeus which shows the Forereef shelf environment. Finally, the third cluster is dominated by all large foraminifera representing the Reef environment. When compared with previous studies, the limestone of Rajamandala Formation in Sukabumi and Rajamandala areas has the same age and depositional environment.

Late Triassic rift tectonics at the northernmost Andean margin (Sierra Nevada de Santa Marta)

Break-up of western Pangaea initiated a back-arc type tectonic setting along the northwestern margin of Gondwana, which resulted in the accumulation of sedimentary and volcanic deposits in extensional basins during the Middle-Late Triassic. The Sierra Nevada de Santa Marta massif, at the northwestern termination of the Andes, exposes Upper Triassic syn-rift successions beneath a voluminous Lower Jurassic volcanic cover. In this contribution, we present a sedimentological and stratigraphical analysis of the Upper Triassic Los Indios and Corual formations, by integrating whole-rock geochemistry, zircon U–Pb geochronology, and a biostratigraphic revaluation of the conchostracan fossil content. We divide the Los Indios Formation into two sandy to conglomeratic and two muddy members. First and third members were deposited in a coarse-grained delta environment. The second and fourth members are interpreted to represent offshore deposits resulting from the encroachment of gravity-flow lobes. Volcanoclastic and volcanic rocks interbedded with sedimentary deposits of the Los Indios and Corual formations record bimodal basic-acid volcanism with a variably alkaline tendency. Based on their alkaline and calc-alkaline signature, and rare earth and trace element patterns, volcanic rocks display a back-arc affinity. With respect to the age of the Los Indios Formation, we recovered conchostracans diagnostic of Upper Carnian and Lower Norian fauna, bearing similarity with faunal assemblages of other Upper Triassic deposits exposed in the northern Andes. The Los Indios and Corual formations are considered as syn-rift successions in a back-arc extension setting. The development of this back-arc basin coincided with the Late Triassic separation of the Oaxaquia, Acatlán, and Chortis terranes during Pangaea break-up. Finally, the Early to Middle Jurassic evolution of the NW Gondwana margin is marked by the inception of a magmatic arc, which characterizes the establishment of Andean-type subduction coeval to ignimbrite flare-up.

Lithofacies characterization and quantitative mineralogical analysis of the sediments from Sahaiawei-1well in the northern Delta Depobelt of the Niger Delta Basin

The sediments of Sahaiawei-1 Well in the Northern Delta Depobelt are represented by sand and shale alternation. Lithofacies characterization and X-ray diffraction technique were used to characterize the sediments from the well in order to characterize the lithofacies, identify the minerals present, determine environment of deposition and identify potential zones for hydrocarbon exploitation. The lithofacies characterization was based on the textural properties, mineralogical composition, fossil content, homogeneity and heterogeneity of the lithofacies units of the well. The lithofacies analysis for Sahaiawei-1 Well identified four (4) lithofacies types of mainly sandstone, shaly sandstone, sandy shale and shale; and fourteen (14) lithofacies zones. The result of the X-ray diffraction analysis identified the following clay minerals – kaolinite, illite/muscovite, chlorite and sepiolite; carbonates and non-clay minerals. Therefore, due to the high percentage of kaolinite in Sahaiawei-1 Well (2% to 39.87%), it could be concluded that pore filing kaolinite may have more effect on the reservoir quality than the pore bridging illite and pore lining chlorite.&#x0D; Keywords: alternation, lithofacies, X-ray diffraction, reservoir, mineralogy

Hoppet - the first fossil-free preschool

The building sector give rise to one fifth of the Swedish greenhouse gas emissions. This sector needs a climate shift to reach the UN Sustainable Development Goals. Local municipalities play an important role in this shift and the City of Gothenburg has therefore initiated an innovation project, Hoppet - the first fossil-free preschool. The purpose is to highlight the climate issue and inspire the industry to develop new fossil-free products and processes as well as promoting existing ones. Hoppet is an initiative leading the way towards a fossil-free society in Gothenburg City, Sweden and the world.Hoppet will be built with minimal climate impact and no fossil resources, as far as possible. This includes everything from production and transport of materials to energy used in the building.The fossil content and climate impact of traditionally built preschools have been calculated as a benchmark for Hoppet. More than 70 % of the 250 building products in a traditionally built preschool has a petroleum-based content, eg plastics. The climate impact of the building products in a traditionally built preschool was calculated to about 390 kg CO2-eq./m2 gross area.The design phase of first Hoppet preschool started in the autumn 2019 and, before materials are chosen, calculations of the actual climate impact are made. Examples of climate calculations and strategies for material selection for Hoppet are presented as well as ongoing and future work for fossil-free construction.For more than two years, the project has scouted for new innovative materials and old techniques in order to build fossil-free. Finding fossil-free and climate neutral products has been challenging. Product development and innovation are key issues for fossil-free construction, as well as communication and collaboration within the construction industry. Five important strategies for the transition into a fossil-free society have been identified; biobased building products, reused and recycled building products, minimized material usage, fossil-free construction site and a product life cycle perspective.