Differences In Provenance Research Articles

Transcriptional profiling reveals distinct classes of parathyroid tumors in PHPT.

The clinical presentation of primary hyperparathyroidism (PHPT) varies widely, although the underlying mechanistic reasons for this disparity remain unknown. We recently reported that parathyroid tumors can be functionally segregated into two distinct groups on the basis of their relative responsiveness to ambient calcium, and that patients in these groups differ significantly in their likelihood of manifesting bone disability. To examine the molecular basis for this phenotypic variation in PHPT, we compared the global gene expression profiles of calcium-sensitive and calcium-resistant parathyroid tumors. RNAseq and proteomic analysis identified a candidate set of differentially expressed genes highly correlated with calcium-sensing capacity. Subsequent quantitative assessment of the expression levels of these genes in an independent cohort of parathyroid tumors confirmed that calcium-sensitive tumors cluster in a discrete transcriptional profile group. These data indicate that PHPT is not an etiologically monolithic disorder and suggest that divergent molecular mechanisms could drive the observed phenotypic differences in PHPT disease course, provenance, and outcome.

Sediment routing and basin evolution in Proterozoic to Mesozoic east Gondwana: A case study from southern Australia

Sedimentary rocks along the southern margin of Australia host an important record of the break-up history of east Gondwana, as well as fragments of a deeper geological history, which collectively help inform the geological evolution of a vast and largely underexplored region. New drilling through Cenozoic cover has allowed examination of the Cretaceous rift-related Madura Shelf sequence (Bight Basin), and identification of two new stratigraphic units beneath the shelf; the possibly Proterozoic Shanes Dam Conglomerate and the interpreted Palaeozoic southern Officer Basin unit, the Decoration Sandstone. Recognition of these new units indicates an earlier basinal history than previously known.Lithostratigraphy of the new drillcore has been integrated with that published from onshore and offshore cores to present isopach maps of sedimentary cover on the Madura Shelf. New palynological data demonstrate progression from more localised freshwater-brackish fluvio-lacustrine clastics in the early Cretaceous (Foraminisporis wonthaggiensis – Valanginian to Barremian) to widespread topography-blanketing, fully marine, glauconitic mudrocks in the mid Cretaceous (Endoceratium ludbrookiae – Albian).Geochronology and Hf-isotope geochemistry show detrital zircon populations from the Madura Shelf are comparable to those from the southern Officer Basin, as well as Cenozoic shoreline and palaeovalley sediments in the region. The detrital zircon population from the Shanes Dam Conglomerate is defined by a unimodal ~1400Ma peak, which correlates with directly underlying crystalline basement of the Madura Province. Peak ages of ~1150Ma and ~1650Ma dominate the age spectra of all other samples, indicating a stable sediment reservoir through much of the Phanerozoic, with sediments largely sourced from the Albany-Fraser Orogen and Musgrave Province (directly and via multiple recycling events). The Madura Shelf detrital zircon population differs from published data for the Upper Cretaceous Ceduna Delta to the east, indicating significant differences in sediment provenance and routing between the Ceduna Sub-basin and central Bight Basin.

Geo-thermochronology of the Saint Antonin basin, south-eastern France

The clastic sedimentary formations of the Saint Antonin basin in the French Maritime Alps contain the record of the Early Oligocene erosional history of the Maures-Esterel massif, Sardinia and Corsica. Detrital apatite fission-track dating and zircon fission-track/U-Pb double dating of samples collected from the Saint Antonin basin confirm sediment provenance and allow obtaining first-order estimates of drainage basin maximum and long-term average exhumation rates. Whereas average exhumation rates were on the order of 0.1–0.2 km/Myr during the Early Oligocene, small parts of the Saint Antonin basin source areas may have experienced maximum exhumation rates on the order of 0.4–0.7 km/Myr. Although zircons and apatites with Early Oligocene fission-track cooling ages make up between 11–15% of the dated grains, a possible volcanic contribution is negligible, as only one single volcanic zircon grain was identified by fission-track/U-Pb double dating. Regional geodynamic processes with convergence in the Western Alps to the east and the end of the Pyreneo-Provençal compression phase by the early Oligocene controlled the differences in basin fill history and sediment provenance between the Saint Antonin basin and the largely contemporaneous Barrême basin in south-eastern France.

The subduction-accretion history of the Bangong-Nujiang Ocean: Constraints from provenance and geochronology of the Mesozoic strata near Gaize, central Tibet

The Mesozoic strata, within the Bangong-Nujiang suture zone in central Tibet, recorded critical information about the subduction-accretion processes of the Bangong-Nujiang Ocean prior to the Lhasa-Qiangtang collision. This paper reports detailed field observations, petrographic descriptions, sandstone detrital zircon U-Pb ages and Hf isotopic analyses from an accretionary complex (preserved as Mugagangri Group) and the unconformably overlying Shamuluo Formation near Gaize. The youngest detrital zircon ages, together with other age constraints from literature, suggest that the Mugagangri Group was deposited during late Triassic-early Jurassic, while the Shamuluo Formation was deposited during late Jurassic-early Cretaceous. Based on the differences in lithology, age and provenance, the Mugagangri Group is subdivided into the upper, middle and lower subunits. These units are younging structurally downward/southward, consistent with models of progressive off-scrapping and accretion in a southward-facing subduction complex. The upper subunit, comprising mainly quartz-sandstone and siliceous mud/shale, was deposited in abyssal plain environment close to the Qiangtang passive margin during late Triassic, with sediments derived from the southern Qiangtang block. The middle and lower subunits comprise mainly lithic-quartz-sandstone and mud/shale, containing abundant ultramafic/ophiolitic fragments. The middle subunit, of late Triassic-early Jurassic age, records a transition in tectono-depositional setting from abyssal plain to trench-wedge basin, with sudden influx of sediments sourced from the central Qiangtang metamorphic belt and northern Qiangtang magmatic belt. The appearance of ultramafic/ophiolitic fragments in the middle subunit reflects the subduction initiation. The lower subunit was deposited in a trench-wedge basin during early Jurassic, with influx of Jurassic-aged zircons originating from the newly active southern Qiangtang magmatic arc. The lower subunit records the onset of arc magmatism related to the northward subduction of the Bangong-Nujiang Ocean. The Shamuluo Formation, comprising mainly lithic-feldspar-sandstone with limestone interlayers, was deposited in a post-collisional residual-sea or pre-collisional trench-slope basin, with sediments derived entirely from the Qiangtang block.

Magnetostratigraphy, age and depositional environment of the Lobo Formation, southwest New Mexico: implications for the Laramide orogeny in the southern Rocky Mountains

AbstractThe Lobo Formation of southwestern New Mexico consists of spatially variable continental successions attributed to the Laramide orogeny (80–40 Myr), although its age and provenance are virtually undocumented. This study combines sedimentological, magnetostratigraphical and geochronological data to infer the timing and origin of the Lobo Formation. Measured sections of Lobo strata at two locations, Capitol Dome in the Florida Mountains and in the Victorio Mountains, indicate significant differences in depositional environments and sediment provenance. At Capitol Dome, where Lobo strata were deposited above a syncline developed in Palaeozoic strata, deposition took place in fluvial, palustrine and marginal lacustrine settings, with alluvial‐fan deposits only at the top of the formation. Combined magnetostratigraphy and a young U–Pb detrital zircon age suggest deposition of the section at Capitol Dome from ~60 to 52 Ma. The Lobo Formation in the Victorio Mountains was deposited in alluvial‐fan and fluvial settings; the age of deposition is poorly bracketed between 66 ± 2 Ma, the weighted‐mean age of two young zircons, and middle Eocene (~40 Ma), the approximate age of overlying volcanic rocks. U–Pb zircon ages from sandstones at the Victorio and Capitol Dome localities indicate that different source rocks provided sediment to the Lobo Formation. Local Proterozoic basement (~1.47–1.45 Ga) dominated the source of the Lobo Formation in the Victorio Mountains, consistent with abundant granitic clasts that are present in the proximal facies there; a diverse range of grain ages suggest that recycled Lower Cretaceous strata provided the dominant source for Lobo Formation sediment at the Capitol Dome locality. The U–Pb data suggest that the depositional systems at the two sites were not connected. Contrasts in depositional setting and detrital zircon provenance indicate that the Palaeogene Lobo Formation in southwest New Mexico was deposited in an assemblage of local depositional settings, possibly in separate structural basins, as a consequence of Laramide tectonics in the region.

Chemostratigraphic and sedimentologic evolution of Wajid Group (Wajid Sandstone): An outcrop analog study from the Cambrian to Permian, SW Saudi Arabia

The Paleozoic age succession in Saudi Arabia represents one of the most prolific petroleum producing systems in the Arabian Peninsula. This succession is also considered important for unconventional tight gas and shale gas reservoirs. The Wajid Group (Wajid Sandstone) in SW Saudi Arabia consists of four formations, namely, Dibsiyah (Lower and Upper), Sanamah, Khusayyayn and Juwayl from bottom to top. This study investigates the major oxides, trace and rare earth elements for the Wajid Group formations in southwestern Saudi Arabia. We characterize and compare the sandstone types, provenance, tectonic setting, and climate. Moreover, we applied the chemostratigraphic technique for stratigraphic differentiation. Concentrations of certain elements indicate that Wajid Group was deposited in a passive continental margin. The geochemical analysis reveals that Wajid Group sediments were likely derived from the upper and bulk continental crust and mafic igneous provenance. The elemental geochemical data has been applied in this study to improve the stratigraphic subdivision and correlation. Using selected elements, geochemical vertical profiles, binary, and ternary diagrams allow clearly distinguishing between Wajid Group formations. Thus supports the established formation boundaries that constructed using lithostratigraphy and sedimentology. The geochemical elements variation between formations can be related to differences in rock-forming minerals, facies change, climate, and provenance. The results of this study may help in constraining and correlating complex facies strata and can be used as a guide for stratigraphic correlations in the subsurface within the Wajid basin and other equivalent stratigraphic successions within Saudi Arabia.

Quantifying the provenance of aeolian sediments using multiple composite fingerprints

Abstract We introduce a new fingerprinting method that uses multiple composite fingerprints for studies of aeolian sediment provenance. We used this method to quantify the provenance of sediments on both sides of the Qinghai-Tibetan Railway (QTR) in the Cuona Lake section of the Tibetan Plateau (TP), in an environment characterized by aeolian and fluvial interactions. The method involves repeatedly solving a linear mixing model based on mass conservation; the model is not limited to spatial scale or transport types and uses all the tracer groups that passed the range check, Kruskal-Wallis H-test, and a strict analytical solution screening. The proportional estimates that result from using different composite fingerprints are highly variable; however, the average of these fingerprints has a greater accuracy and certainty than any single fingerprint. The results show that sand from the lake beach, hilly surface, and gullies contribute, respectively, 48%, 31% and 21% to the western railway sediments and 43%, 33% and 24% to the eastern railway sediments. The difference between contributions from various sources on either side of the railway, which may increase in the future, was clearly related to variations in local transport characteristics, a conclusion that is supported by grain size analysis. The construction of the QTR changed the local cycling of materials, and the difference in provenance between the sediments that are separated by the railway reflects the changed sedimentary conditions on either side of the railway. The effectiveness of this method suggests that it will be useful in other studies of aeolian sediments.

Climate change and response in bottom water circulation and sediment provenance in the Central Arctic Ocean since the Last Glacial

In this study, Arctic Ocean patterns of deep water circulation and sediment provenance during the Last Glacial (LG) were compared with the recent situation by investigating the Nd and Sr isotopic composition (143Nd/144Nd, expressed as εNd, 87Sr/86Sr) of the leachable and lithogenic sediment fractions as well as the elemental composition (Mn, Ca, Mg, total inorganic carbon (TIC)) on a spatially extended scale encompassing 11 sediment cores from several Arctic Ocean basins and ridges.The leachable, authigenic signature of the surface sediments implies a North Atlantic deep water source and a late Holocene circulation regime that leads to well-mixed, mostly uniform, εNd values of −10.9 to −10.3. Sediments from the LG have overall more variable authigenic εNd values (−13.9 to −7.4). Lower values specifically occur in the Amerasian and Amundsen Basins, documenting an enhanced flow of deep waters from the Makarov Basin to the Amundsen Basin probably via the Lomonosov Ridge intra-basin.In terms of detrital provenance areas, the lithogenic material deposited at the core locations cannot be unambiguously assigned to distinct source areas based on its radiogenic isotope composition, but represents a diverse mixture. Nevertheless, the Nd and Sr isotope signatures of surface sediments from the Amerasian Basin are dominated by western Arctic sources (εNd=−12.8 to −11.0; 87Sr/86Sr=0.7214 to 0.7251), while Eurasian Basin surface sediments are dominated by Eurasian sources (εNd=−10.9 to −9.7, 87Sr/86Sr=0.7178 to 0.7299), which is in agreement with previous studies. Bulk element patterns (Ca, Mg, TIC) of the studied sediments support these differences in provenance. The LG samples show the same trends with low εNd (−16.1 to −13.7) and high 87Sr/86Sr (0.7294) in the Canada Basin, and higher εNd (−12.6 to −8.8) and lower 87Sr/86Sr (0.7154 to 0.7249) in the Eurasian Basin sediments. However, LG samples have mostly lower and more heterogenous εNd and 87Sr/86Sr values than the surface samples.Our geochemical study shows that the overall circulation pattern of the deep water masses during the LG was locally influenced by brine formation but was generally similar to today. The isotopic composition of the lithogenic material from the LG is different from modern times, presumably due to shorter transport pathways of lithogenic material to the Arctic Ocean because of a lower sea level and exposed shelves during the LG. Nevertheless, the lithogenic fraction still represents a mixture from several sources.

Bitterfeld amber is not Baltic amber: Three geochemical tests and further constraints on the botanical affinities of succinite

Baltic and Bitterfeld ambers are important deposits of polymerized conifer resin that are widely recognized for their exquisite fossil inclusions, especially insects. Because of over-arching similarities with respect to visual appearance, organic geochemistry, arthropod assemblages, and proximity to forests of the Paleogene North Sea margin, these two ambers have not yet been differentiated definitively, leading to ongoing debate as to whether or not they (and their respective inclusions) are truly equivalent. We combine micro-Fourier transform infrared spectroscopy (FTIR), time of flight-secondary ion mass spectrometry (ToF-SIMS), and stable isotopes (δ13C and δ2H) to establish that Baltic and Bitterfeld ambers differ consistently in their geochemical properties, and thus capture distinct depositional episodes in space, but not necessarily in time. Baltic amber has more succinic acid, succinic anhydride, and communic acid relative to Bitterfeld amber, but less dehydroabietic acid. Although both ambers produce overlapping δ13C values, supporting a similar age of formation, δ2H is markedly depleted (by ~20‰) in Baltic amber relative to Bitterfeld amber. The hydrogen isotopic results confer paleolatitudinal differences in amber provenance, that is, a clear differentiation between sources originating from the northern (Baltic) and southern (Bitterfeld) margins of the Paleogene North Sea. We conclude that the two deposits are geologically distinct in origin, but that similarities in their respective faunal records arise because they are broadly coeval in time. We also present new ToF-SIMS results that imply only resins from modern conifers of the families Pinaceae and Sciadopityaceae begin to satisfy the expanded geochemical profiles presented for Baltic and Bitterfeld ambers.

Basin evolution of Upper Cretaceous–Lower Cenozoic strata in the Malargüe fold‐and‐thrust belt: northern Neuquén Basin, Argentina

AbstractThe Andean Orogen is the type‐example of an active Cordilleran style margin with a long‐lived retroarc fold‐and‐thrust belt and foreland basin. Timing of initial shortening and foreland basin development in Argentina is diachronous along‐strike, with ages varying by 20–30 Myr. The Neuquén Basin (32°S to 40°S) contains a thick sedimentary sequence ranging in age from late Triassic to Cenozoic, which preserves a record of rift, back arc and foreland basin environments. As much of the primary evidence for initial uplift has been overprinted or covered by younger shortening and volcanic activity, basin strata provide the most complete record of early mountain building. Detailed sedimentology and new maximum depositional ages obtained from detrital zircon U–Pb analyses from the Malargüe fold‐and‐thrust belt (35°S) record a facies change between the marine evaporites of the Huitrín Formation (ca. 122 Ma) and the fluvial sandstones and conglomerates of the Diamante Formation (ca. 95 Ma). A 25–30 Myr unconformity between the Huitrín and Diamante formations represents the transition from post‐rift thermal subsidence to forebulge erosion during initial flexural loading related to crustal shortening and uplift along the magmatic arc to the west by at least 97 ± 2 Ma. This change in basin style is not marked by any significant difference in provenance and detrital zircon signature. A distinct change in detrital zircons, sandstone composition and palaeocurrent direction from west‐directed to east‐directed occurs instead in the middle Diamante Formation and may reflect the Late Cretaceous transition from forebulge derived sediment in the distal foredeep to proximal foredeep material derived from the thrust belt to the west. This change in palaeoflow represents the migration of the forebulge, and therefore, of the foreland basin system between 80 and 90 Ma in the Malargüe area.

Heavy minerals in the late Eocene sandstone of Medicine Pole Hills, southwestern North Dakota

Late Eocene sandstone capping hills and small buttes in the Medicine Pole Hills in southwestern North Dakota has been correlated with the Chalky Buttes Member of the Chadron Formation. Heavy-mineral analysis was used to assess this correlation. Optical microscopy and chemical analysis using a scanning electron microscope/energy dispersive spectrometer (SEM/EDS) system were used to determine abundances and compositions of heavy minerals separated from 0.25–0.30 mm fractions of nine samples from seven depositional units (353–602 grains per sample). The 0.063–0.125 mm fraction was also studied for one of these samples. Samples ranged from coarse- to medium- to fine-grained poorly consolidated sandstone. Total heavy mineral recovery (0.4–14.1%) generally corresponded with the grain-size distribution of samples, with higher recoveries in coarser samples. Opaque grains (ferruginous aggregates, Fe-Ti oxides, and leucoxene) comprised 0.8–15.6 percent of heavy mineral grains. Non-opaque grains were dominated by amphibole (24.4–52.2%) and epidote-clinozoisite (10.6–38.1%), with variable diopside (0–51.1%). Generally less abundant minerals included garnet, apatite (bone fragments), biotite, and muscovite. One sample was biotite-rich (36.5%). Chemical compositions of heavy minerals showed no significant stratigraphic variations, suggesting the nature of the sources did not vary. Diopside, biotite, and approximately 1/3 of the amphibole grains were interpreted as derived from Tertiary volcanic sources. The majority of the amphibole grains (tremolite and blue-green hornblende), epidote, and garnet were derived from Precambrian metamorphic sources. The relative contribution of volcanic sources was variable (19–64%), being highest in those samples with more diopside and (with the exception of the biotite-rich sample) highest in those samples with higher overall heavy-mineral abundances. Individual heavy-mineral abundances also correlated fairly well with grain size. Overall, variations in heavy minerals were explained by variable volcanic source contributions and variations in grain-size distributions of the samples. Despite the variability found, cluster analysis showed that the samples from Medicine Pole Hills were consistently different than the generally much more stable heavy-mineral assemblages found in the Chalky Buttes Member. They were also consistently different when volcanic heavy minerals were ignored. The differences could not be explained by variable volcanic contributions, grain-size effects, and/or differences in heavy mineral stabilities alone. They require differences in provenance, suggesting that the sandstone of Medicine Pole Hills should not be correlated with the Chalky Buttes Member, or, at the very least, it should be considered a distinct facies of the Chalky Buttes Member.

Dynamics of the late Plio–Pleistocene West Antarctic Ice Sheet documented in subglacial diamictites, AND-1B drill core

Geologic studies of sediment deposited by glaciers can provide crucial insights into the subglacial environment. We studied muddy diamictites in the ANtarctic geological DRILLing (ANDRILL) AND-1B drill core, acquired from beneath the Ross Ice Shelf in McMurdo Sound, with the aim of identifying paleo-ice stream activity in the Plio–Pleistocene. Glacial advances were identified from glacial surfaces of erosion (GSEs) and subglacial diamictites within three complete sequences were investigated using lithofacies associations, micromorphology, and quartz sand grain microtextures. Whereas conditions in the Late Pliocene resemble the modern Greenland Ice Sheet where fast flowing glaciers lubricated by surface meltwater terminate directly in the sea (interval 201–212mbsl) conditions in the Late Pleistocene are similar to modern West Antarctic Ice Sheet (WAIS) ice streams (38–49mbsl). We identify the latter from ductile deformation and high pore-water pressure, which resulted in pervasive rotation and formation of till pellets and low relief, rounded sand grains dominated by abrasion. In the transitional period during the Mid-Pleistocene (55–68mbsf), a slow moving inland ice sheet deposited tills with brittle deformation, producing lineations and bi-masepic and unistrial plasma fabric, along with high relief, conchoidally fractured quartz grains. Changes in the provenance of gravel to cobble-size clasts support a distant source area of Byrd Glacier for fast-flowing paleo-ice streams and a proximal area between Darwin and Skelton Glaciers for the slow-moving inland ice sheet. This difference in till provenance documents a shift in direction of glacial flow at the core site, which indirectly reflects changes in the size and thickness of the WAIS. Hence, we found that fast ice streaming motion is a consequence of a thicker WAIS pushing flow lines to the west and introducing clasts from the Byrd Glacier source area to the drill site. The detailed analysis of diamictites in AND-1B demonstrates that Pliocene glacial intervals were warmer than in the Pleistocene when polar ice sheets grew from local inland ice to regional ice streams.

The Research on the Depositional Systems Types and Characteristics of Sublacustrine Fan Deposits in the Second Member of Dongying Formation, Liaodong Bay

Integrated employment of wireline logging and seismic data, turbidite fan types and distribution characteristics were analyzed in the Paleogene strata of the second Member of Dongying Formaiton. The results showed that: the study area developed many types of turbidite fan, including the slump turbidite fans, deepwater turbidite fan, steep nearshore turbidite fan, far shore slope turbidite fan, etc. There are significant differences in the developmental environment, sedimentary characteristics, the main factors and so on. The differences in delta size, provenance, ancient terrain and triggering mechanism affect the development of different turbidite fan deposits. By identifying wireline logs stacking patterns, the external geometry and internal reflection structure of seismic events, the types of lacustrine fan identification modes were determined. And also with three-dimensional seismic attribute analysis techniques for predicting sublacustrine fan and determining the plane distribution, it provide basic geological evidence for lacustrine fan hydrocarbon reservoir exploration.

Provenance and depositional conditions of Cretaceous–Paleogene boundary sandstones from northeastern Mexico

We compare Late Maastrichtian siliciclastic sandstone in northeastern Mexico with those representing the Cretaceous–Paleogene (K–Pg) boundary to reveal differences in provenance and depositional conditions between background sedimentation and K–Pg sand. Lithology and compositional variations are presented for the deep-water Burgos Basin and the shallow-water La Popa Basin.The Late Maastrichtian sandstones in the Burgos Basin have sharp lower contacts, contain abundant trace fossils and are separated by meter-thick marl layers. They represent sporadic mass flows from coastal areas separated by long phases of hemipelagic sedimentation. The K–Pg sandstone layers are amalgamated, contain thin marl intercalations only in the uppermost part and trace fossils are present in the top sandstone layer only. Also this succession represents mass-flow deposits, but the sand may have been deposited during a very short period. The La Popa Basin sandstones represent deltaic sedimentation interrupted by submarine channel deposition during the K–Pg boundary transition with abundant rip-up clasts and bioclasts at the base.The sandstones of the Burgos Basin are quartz to akosic wacke dominated by quartz (>90%) and some feldspar (<10%) in calcite cement and matrix. Lithic fragments are rare and dominated by chert and bioclasts. Ultra-stable heavy minerals (ZTR=50–80) and plutonic quartz grains (ca. 40% of the total quartz population) are particularly common in the K–Pg sandstones. In the Maastrichtian sandstones, metamorphic heavy minerals, particularly chlorite, clinozoisite, and tourmaline (20–50% of the heavy mineral population), and metamorphic quartz (80% of the quartz population) have higher abundances. The La Popa sandstones are subarkose to arkose and arkosic wacke and have a high abundance of feldspar (15–30%) and lithic fragments (5–20%), mainly of siltstone and carbonate. The sandstones from both basins have chemical compositions typical for recycling (Zr/Sc=12–27 and 17–140 in the Burgos and La Popa Basin, respectively) and influences from mafic source rocks (Th/Sc=0.4–1.1; Ti/Nb=350–510). Therefore we suggest that all studied successions share a common provenance with transport of recycled orogenic metasedimentary components from northwestern Mexico and magmatic arc material from western Mexico. Subsequently, longshore currents mixed the detritus with limestone clasts derived from the tectonically active Sierra Madre Oriental, which probably is the cause for compositional changes in the sandstones. Due to increased sediment input from western Mexico at the K–Pg boundary, provenance changes cannot be related to the Chicxulub impact.

Provenance and family variation in seed mass and fruit composition in Sclerocarya birrea sub-species caffra

Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (Marula) is one of the traditionally important indigenous multi-purpose fruits trees in Africa, which has been commercialized as its fruits and processed nuts/kennels have entered local, regional and international trade. This study was an analysis of the variation between and within provenances of S. birrea sub-species caffra with respect to seed mass of dried fresh seed, total soluble solids (total sugars) content of fresh fruits, and the vitamin C content of fresh fruits as well as family heritabilities of fruit parameters and seed mass. A nested sampling procedure was followed for where there were four areas (provenances), eight to ten families (parent trees) and fifty fruits per family. There were significant differences in provenance and family in seed mass (p=0.06 and p=0.0001) and vitamin C (p=0.001 and p=0.0001), total soluble solids lacked provenance variation (p=0.35) but had wide family variation (p=0.0001). There was no correlation between parameters except a significant correlation between rainfall intensity and total soluble solids content; lower the rainfall higher the sugar content and the higher the rainfall the lower the sugar content (p=0.06). The most variable parameter was vitamin C with the highest family heritability, however all traits had relatively high family heritabilities (above 0.5). It was concluded that the results of fruit composition and seed mass could be of remarkable importance in the identification of superior genotypes, making use of the wide family variation that exists. A study to capture a wider range of provenances and families including studying the environmental parameters of soils, rainfall and altitude for more precision. Key words: Traits, parameters, correlation, variance.

A heavy mineral study of sandstones from the eastern Murzuq Basin, Libya: Constraints on provenance and stratigraphic correlation

This paper presents the results of an integrated heavy mineral and mineral chemical study of Precambrian–Mesozoic clastic sediments from the eastern Murzuq Basin. The purpose of this study was to constrain the provenance of sediment and to assess the value of heavy minerals as a stratigraphic tool. Conventional heavy mineral analysis was carried out on 64 samples, tourmaline geochemical analysis on 25 samples, garnet geochemical analysis on four samples, rutile geochemical analysis on 21 samples, and clinopyroxene geochemical analysis on two samples. The study indicates that heavy mineral analysis is a valuable tool for understanding the provenance of Palaeozoic and Mesozoic clastic sediments in Libya, despite the intense weathering that surface samples have undergone. Based on heavy mineral ratios and mineral chemical data, there appear to be three key events when the provenance signature changed within the Palaeozoic–Mesozoic sedimentary succession at the eastern Murzuq Basin: (i) at the base of the Tanezzuft Formation (early Silurian), (ii) at the base of the Tadrart Formation (Early Devonian), and (iii) at the base of the Mrar Formation (Carboniferous), subdividing the succession into four intervals (Hasawnah–Mamuniyat, Tanezzuft–Akakus, Tadrart–Awaynat Wanin, and Mrar–Nubian). There is probably also an event between the Precambrian and the Hasawnah Formation (Cambrian), but there are currently insufficient data to prove this unequivocally. Comparing data of the present study with results from the previous work in the Kufra Basin it is evident that heavy mineral data provide useful evidence for differences in provenance both regionally and stratigraphically in basins of the central Sahara.

Genesis of upland soils, Lewes Plateau, central Yukon. Part 1: soils formed on Pleistocene glacial deposits

Dampier, L., Sanborn, P., Smith, S., Bond, J. and Clague, J. J. 2011. Genesis of upland soils, Lewes Plateau, central Yukon. Part 1: soils formed on Pleistocene glacial deposits. Can. J. Soil Sci. 91: 563–578. We describe and interpret nine upland (&gt;1000 m asl) Dystric Brunisols and one Humo-Ferric Podzol formed on till of the McConnell [Marine Isotope Stage (MIS) 2] and penultimate (MIS 4 or 6) glaciations on the Lewes Plateau of central Yukon Territory. Unlike soils formed on correlative glacial deposits at lower elevation in the nearby Tintina Trench, the soils on the Lewes Plateau display only weak age-related differences. Penultimate and McConnell soils have solum thicknesses of 50–75 cm and &lt;50 cm, respectively, but other morphological and chemical properties do not differ between the two age groups. Smectite is present in the McConnell soils; it was previously reported only in soils formed on Early Pleistocene glacial deposits in central Yukon and was interpreted to reflect weathering and soil formation during warm interglaciations. Paleoclimatic interpretations of clay mineralogy in central Yukon may be confounded by differences in parent material provenance and should be reassessed. This study shows that field soil characteristics alone are insufficient to differentiate McConnell and penultimate glacial deposits in upland landscape positions on the Lewes Plateau.

Evidence for a core gut microbiota in the zebrafish

Experimental analysis of gut microbial communities and their interactions with vertebrate hosts is conducted predominantly in domesticated animals that have been maintained in laboratory facilities for many generations. These animal models are useful for studying coevolved relationships between host and microbiota only if the microbial communities that occur in animals in lab facilities are representative of those that occur in nature. We performed 16S rRNA gene sequence-based comparisons of gut bacterial communities in zebrafish collected recently from their natural habitat and those reared for generations in lab facilities in different geographic locations. Patterns of gut microbiota structure in domesticated zebrafish varied across different lab facilities in correlation with historical connections between those facilities. However, gut microbiota membership in domesticated and recently caught zebrafish was strikingly similar, with a shared core gut microbiota. The zebrafish intestinal habitat therefore selects for specific bacterial taxa despite radical differences in host provenance and domestication status.

2H stable isotope analysis of human tooth enamel: a new tool for forensic human provenancing?

Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well-recognised and increasingly important method for determining the provenance of human remains, and it has been used successfully in bio-archaeological studies as well as forensic investigations. In particular, (18)O and (2)H stable isotope signatures of bone and hair, respectively, are well-established proxies of climate (temperature) and source water and are therefore considered as indicators of geographic life trajectories of animals and humans. While the methodology for (2)H analysis of human hair, fingernails, and bone collagen is currently used to determine human provenance, i.e. geographic origin and identify possible migration patterns, studies involving the analysis of (2)H in tooth enamel appear to be nonexistent in the scientific literature. Ground tooth enamel was analysed by continuous-flow isotope ratio mass spectrometry (IRMS) coupled on-line to a high-temperature conversion elemental analyser (TC/EA). An array of tooth enamel samples from archaeological and modern teeth has been analysed under different experimental conditions, and the results of this proof-of-concept study are presented. While no significant differences in (2)H abundance were noted as a result of H exchange studies or different sample preparation protocols, no significant differences or trends in measured δ(2)H-values were observed either with regard to known differences in geographical provenance. We concluded that the δ(2)H-values obtained from tooth enamel could not be used as proxy for a person's geographical origin during adolescence.

Evolution in the provenance of a tectonically controlled Plio–Pleistocene alluvial system between the Variscan Iberian Massif and the Atlantic margin, Portugal

Geochemical and mineralogical data from a Pliocene to Pleistocene alluvial sequence are integrated to access the factors that control rare earth elements (REE) geochemistry and the evolution and spatial differences in provenance. The studied alluvial system is situated in a tectonic active setting at the contact between the Variscan Massif, with several Paleozoic and Precambrian units that support a coastal range, and the Atlantic margin. REE and HREE abundances are generally higher in swamp-lake than in floodplain sediments. The majority of the REE in floodplain sediments is hosted by Y and Th-bearing minerals and illite; in swamp-lake sediments is also probable an association with organic matter. The high Gd/Yb, Eu/Eu* and kaolinite content in older sediments suggest that during the earlier phases provenance was mainly from the hinterland (weathered granitic rocks and its sediment cover). The subsequent illite (Mg-rich) clay assemblages and REE patterns indicate mainly lateral input from the eastern basin edge (Palaeozoic and Precambrian metapelitic rocks). These sediments tend to have lower Gd/Yb and La/Sm than their source rocks. The analysis of the chemical index of alteration (CIA) indicates that although a north-directed fluvial axis existed at that time the “mature” basin edge units found to the south (Silurian) had a limited role in supplying sediments. This shift in provenance is attributed to the uplift of the coastal range. Afterwards, the contribution of recycled Cretaceous and Cenozoic sedimentary units increased progressively. This is demonstrated by the increase is SiO 2/TiO 2, CIA and kaolinite/illite when the climatic conditions are expected to have become less chemically aggressive.