Stratigraphy, petrology, and depositional environments of the Jarvis creek coalfield, Alaska

Jarvis Creek basin coals are subbituminous, low in ash, and increase upsection in moisture, most major oxides and trace elements, and vitrinite with subsequent liptinite and inertinite decreases. Sulfide mineral deposits east-southeast of the basin are responsible for the enrichment of the upper coals in sulfur and metals. Sandstones are quartzose, arkosic, and lithic in the lower, middle, and upper units respectively, and were derived from a recycled orogen provenance. Sediment transport was from the south at the base, shifting to an easterly source higher in the section. Deposition was by braided and meandering streams on mid and distal portions of alluvial fans. The lower and middle units are correlative with the Healy Creek Formation, while the upper unit probably correlates with the Lignite Creek Formation. Measured, indicated, and inferred coal reserves are 17, 37, and 227 million short tons respectively, mostly in the upper unit at shallow depths.Presented to the Faculty of the University of Alaska in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENC

The Triassic Saharonim Formation of the Sephardic Province on the Southern Tethyan Margin Is an Analog for the Triassic Germanic Muschelkalk of Western Europe

The Germanic Muschelkalk consists of a sedimentary sequence of limestone and dolostone units that overlies the Permian Buntsandstein Formation and underlies the Middle and Late Triassic Keuper Formation. The three formations form the Germanic Triassic Supergroup. The Muschelkalk was deposited in a shallow marine environment that was only partially connected to the Tethys Ocean to the south with the middle section evaporitic indicating a restricted basin. Fossiliferous beds are often biostromal such as the well-known Coenothyris brachiopod beds (e.g. Terebratula Bed, terebratulid facies) common in the Muschelkalk. The Saharonim Formation of the Sephardic Province, found along the southern shore of the Tethys Ocean, consists of limestone and shale beds with occasional marls and bioturbated micrites. The formation is rich in marine fossils, especially the Fossiliferous Limestone Member from Makhtesh Ramon, southern Israel where the brachiopod genera Coenothyris and Tunethyris are common. The formation was also deposited in an open shelf environment that is indicative of the main transgressive phase of the Middle Triassic in the area. A shallow marine depositional environment is suggested by the numerous and diverse nautiloid population. The Saharonim Formation is similar to the Germanic Muschelkalk in that the lithology is comparable and the fossil constituents, although more diverse, are similar, especially among the brachiopods. Characteristic fossils common to both include: Encrinus, Ceratites, Germanonautilus, Lima, Myophoria, Plagiostoma, Hybodus and Nothosaurus

A Dielasma Community from the Triassic of Makhtesh Ramon, Southern Israel

The cosmopolitan brachiopod Dielasma ranges from the Upper Mississippian through the Upper Triassic. In southern Israel a new Dielasma community is recognized from the Triassic Saharonim Formation, Ramon Crater. The shells represent a new species and are very strongly sulciplicated, a feature that seems to be more prevalent in the Mesozoic than the Paleozoic. The Saharonim Formation was deposited under normal, calm, relatively shallow marine conditions as part of the global transgression of the Early Ladinian sea. There is no evidence of evaporitic or dolomitic sediments. The complete absence of scouring within the carbonates or signs of channeling and ripple marks implies that most of the Fossiliferous Limestone Member from which the shells were collected was deposited at least beneath wave base (at a paleolatitude of within 10°N) and may have been deposited even at a depth of between 100 to 200 m. Faunal constituents of the Saharonim Formation include conodonts, ostracods, foraminiferans, bivalves, cephalopods, gastropods, echinoderms and vertebrate remains that belong to the Sephardic Province and are diagnostic of the Middle Triassic series of Israel. The faunal composition and shallow depositional environment of the strata studied are useful in correlating the Triassic rocks in the Negev with those in Europe, and helps differentiate the Sephardic Province from the Germanic Muschelkalk and the Alpine Tethyan faunas to the north

Are Petroglyphs Markers for Frontier Boundaries or Directional to Raw Material Resources?

The Shawangunk, NY region is known for rich mineral resources: anomalous concentrations of quartz crystals; native silver; silver, copper and zinc sulfides; and minimal quantities of native gold. The Shawangunks also host Native American petroglyphs carved into local bedrock. Although the Shawangunks are rich in metallic ores and semiprecious minerals, the entire range is sorely deficient in chert and other raw materials used for prehistoric subsistence. Despite the lack of raw materials for subsistence needs, archaeological tools found in the area are strikingly similar in raw-material type, as well as general morphology, to quarry-extraction tools discovered in the adjacent Wallkill Valley. The Wallkill Valley contains hundreds of prehistoric chert quarries occurring in Cambro-Ordovician carbonates. Recovered objects are fashioned from metaconglomerates, arkoses, quartzites, and argillites occurring within the graded sequences of the middle to upper Silurian Shawangunk Formation. The formation extends from Rosendale, NY southward into Virginia and unconformably overlies shales and graywackes of the Ordovician Martinsburg Formation. The Shawangunk Ridge in the vicinity of New Paltz, NY consists of gray to white conglomerate and quartzite, with milky quartz pebbles and rose quartz in the upper part of the formation. It pinches out near Binnewater, NY. Tools weigh up to 10 kg and are battered on all surfaces. Some surfaces show pitting, grinding and abrasion. Ruptures occurring along joint surfaces, or joint-bedding intersections, are flaked backward to prepare a wedge-like impact surface. The full complement of rock types occurring within the graded sequence are exploited for their durability in production of tools. Morphologically the objects fit categorically into the chain of operation of lithic production described for Wallkill Valley chert quarries. Considering the paucity of subsistence raw material in the Shawangunks, what does the richness of petroglyphs and extraction tools signify? Do petroglyphs represent territorial/frontier boundaries or limits of raw-material resources? Perhaps the petroglyphs mark the entranceway to sources of commodity minerals employed for personal adornment, ideological activities or internment

Taxonomy, Paleobiogeography and Paleoecology of Jurassic Ethiopian Brachipods: A Progress Report

The area under study belongs to the Jurassic Ethiopian Province (western North Africa, Egypt, Israel, Jordan, Saudi Arabia, Ethiopia, Eritrea, Kenya, Madagascar and Kachchh). Work was begun in 1978 in northern Sinai with the discovery of the large, rare Callovian brachiopod Septirhynchia hirschi and subsequent sampling of 6,000 feet of sediment at Gebel Maghara and Gebel Engabashi. In the Negev, southern Israel, we described a brachiopod fauna from the Matmor Formation that was deposited on a low energy, peritidal, shallow marine shelf. During the latter part of the Jurassic we recognize a connection with the pelagic western Neotethys. Some brachiopod genera are common in northern Sinai (e.g. Sphriganaria, Ectyphoria, Sinaithyris) but are missing in the Negev (Hamakhtesh Hagadol). Daghanirhynchia is abundant in Jordan and Sinai but absent in the Negev. We are investigating the reasons for this anomalous distribution pattern as well as the reasons for the large degree of endemism in the province. Current work in progress includes a further study of brachiopod faunas of the southern Tethyan margin, specifically in the Negev, southern Israel, and Mt. Hermon, northern Israel, Gebel Maghara and Gebel Minshera, northern Sinai, and Wadi Zarqa, northwest Jordan. Upon completion of these projects we expect to correlate the Jurassic strata across the Dead Sea Rift from Israel to Jordan and complete a study of the paleocommunities in the region

Dielasma or Tunethyris? A Taxonomic Conundrum

A new species of a dielasmid brachiopod from the Triassic Saharonim Formation of Makhtesh Ramon, southern Israel, was discovered in Anisian-Ladinian limestones that alternate with calcareous shales. The environment of deposition was an open shelf with normal salinity. The new species is homeomorphic with Paleozoic forms, but may not belong to the genus Dielasma; however, it may be a species of Tunethyris, a Triassic genus from Tunisia. If the Triassic specimens belong to the Paleozoic genus Dielasma, an important new Lazarus genus is added to the systematic literature. However, if the specimens belong to the Triassic Tunethyris, there are important paleobiogeographic considerations to be noted, such as the significance of the enigmatic Ladinian crisis and the influence of the Hispanic Corridor, an immature seaway connecting the western Tethys with eastern Panthalassa that may have been open sporadically during the Late Triassic and affected brachiopod distribution. Points favoring the selection of Tunethyris are: 1. The orientation of the crura in the new species is slightly different from Paleozoic dielasmids, especially D. elongatum from the Permian of Germany; 2. the anatomy of Tunethyris punica from the Norian of Tunisia is very similar to the new species and the anterior commissure of both is sulicplicate, a feature not found in Paleozoic forms; 3. The loop of the Israeli brachiopods is acuminate. In addition to other anatomical characters that support the erection of a new species, Tunethyris calzada has a septalium supported by a median septum whereas the septalium in the brachiopods from Makhtesh Ramon rests on the valve floor

Radically enhanced molecular recognition

The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host–guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication

Probing the limits of selectivity in a recognition-mediated reaction network embedded within a dynamic covalent library

This work was supported by the award of a Postgraduate Studentship from EPSRC (EP/K503162/1) to TK.Two recognition-mediated reaction processes operating through a reactive binary complex drive resolution of a 24-component dynamic covalent library, assembled from individual aldehydes and nucleophiles. The effectiveness of the library resolution and selective amplification of one recognition-enabled species over another is limited by the difference in the rates of the recognition-mediated reactive processes and strength of the recognition processes employed in the dynamic system.PostprintPeer reviewe

Human-based fibrillar nanocomposite hydrogels as bioinstructive matrices to tune stem cell behavior

The extracellular matrix (ECM)-biomimetic fibrillar structure of platelet lysate (PL) gels along with its enriched milieu of biomolecules has drawn significant interest in regenerative medicine applications. However, PL-based gels have poor structural stability which severely limits its performance as a bioinstructive biomaterial. Here, rod-shaped cellulose nanocrystals (CNC) are used as a novel approach to modulate the physical and biochemical microenvironment of PL gels enabling their effective use as injectable human-based cell scaffolds with a level of biomimicry that is difficult to recreate with synthetic biomaterials. The incorporation of CNC (0 to 0.61 wt.%) into the PL fibrillar network during the coagulation cascade leads to decreased fiber branching, increased interfiber porosity (from 66 to 83%) and modulate fiber (from 1.4 ± 0.7 to 27 ± 12 kPa) and bulk hydrogel (from 18 ± 4 to 1256 ± 82 Pa) mechanical properties. As result of these physicochemical alterations, nanocomposite PL hydrogels resist to the typical extensive clot retraction (from 76 ± 1 to 24 ± 3 at Day 7) and show favored retention of PL bioactive molecules. The feedback of these cues on the fate of human adipose-derived stem cells is evaluated, showing how it can be explored to modulate the commitment of encapsulated stem cells toward different genetic phenotypes without the need for additional external biological stimuli. These fibrillar nanocomposite hydrogels allow therefore to explore the outstanding biological properties of human-based PL as an efficient engineered ECM which can be tailored to trigger specific regenerative pathways in minimal invasive strategies.The authors thank the Hospital da Prelada (Porto, Portugal) for providing adipose tissue samples. The authors acknowledge the financial support from project Recognize (UTAP-ICDT/CTM-BIO/0023/2014), project NORTE-01-0145FEDER-000021 supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), the European Union Framework Programme for Research and Innovation HORIZON 2020, under the TEAMING Grant agreement No. 739572 – The Discoveries CTR EU, Forecast 668983, Marie Skłodowska-Curie grant agreement No. 706996 (PrinTendon) and CHEM2NATURE 692333; FCT/MCTES (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia, e Ensino Superior) and the Fundo Social Europeu através do Programa Operacional do Capital Humano (FSE/POCH) in the framework of PhD grant PD/59/2013 – PD/BD/113807/2015 for BBM, Post-Doc grant SFRH/BPD/112459/2015 for R.D.info:eu-repo/semantics/publishedVersio