Mountain Group Research Articles

Provenance of Permian Delaware Mountain Group, central and southern Delaware Basin, and implications of sediment dispersal pathway near the southwestern terminus of Pangea

ABSTRACTThe Delaware Basin is located near the southwestern end of the Alleghanian–Ouachita–Marathon orogenic belt. The basin is mostly filled by Permian clastic rocks of the Delaware Mountain Group with ramp- to shelf-carbonate rimming basin edges. The Delaware Mountain Group has been well-documented as a deep-water clastic reservoir unit in the prolific Permian Basin, but its sources and related sediment dispersal pathways remain inconclusive. In this study, a total of 55 samples of the Delaware Mountain Group were collected from whole core and sidewall core from the central and southern Delaware Basin, and sandstone modal analyses and U-Pb detrital zircon geochronology were applied to constrain their potential sources. Sandstone modal analyses show that the majority of samples fall within the transitional continental source field. Age spectra of detrital zircon from five selected samples include a prominent middle Palaeozoic age cluster (~490–275 Ma), a major Neoproterozoic to early Palaeozoic age cluster (~790–510 Ma), and a series of minor age clusters of the middle to late Mesoproterozoic (~1300–920 Ma), early Mesoproterozoic (~1600–1300 Ma), late Palaeoproterozoic (~1825–1600 Ma), and Archaean and Palaeoproterozoic (> ~1825 Ma). Integrating detrital zircon data from all potential sources and coeval sandstones from the northern Delaware Basin suggests that the majority of sediment was derived from the Appalachian foreland, the Ouachita orogenic system, and the peri-Gondwanan terranes. Variation in the abundance of the different age groups reveals a provenance shift between deposition of the Brushy Canyon Formation and the Cherry and Bell Canyon Formations. To accommodate the composition, and the stratigraphic and spatial age spectral variations, we proposed that the sediment dispersal pathway includes a transcontinental fluvial system from the Appalachian orogenic belt to the east, a regional scale fluvial system from the Ouachita orogenic belt to the north and northeast, and a local, proximal fluvial system from the peri-Gondwanan terranes to the south and southeast.

AMS Radiocarbon Dates on Peat Section Related with Tephra and Archaeological Sites in Carlisle Island, the Islands of Four Mountains, Alaska

ABSTRACTWe obtained radiocarbon (14C) dates with accelerator mass spectrometry (AMS) of vascular plant samples and a charcoal sample collected from peat deposits near the prehistoric village site informally designated CR-03 on Carlisle Island in the Islands of Four Mountains group, Alaska, to determine the eruption age of the CR-02 tephra. A fine vitric ash erupted from Okmok caldera, Umnak Island (ca. 2 ka BP) was also discovered in the bog. The ages of the CR-02 tephra and Okmok II ash are estimated to be 1050 and 2000 cal BP, respectively. Because both tephras are distinctive and widespread, these are important chronostratigraphic markers for archaeological sites in this island group. The 14C dates obtained from this bog are 800 years younger than the dates of the charcoal fragments from cultural layers in the Unit 3 of prehistoric village site CR-02 (AMK-0003).

Диатомовые комплексы донных отложений оз. Щучье (Хибинский горный массив, Кольский п-ов)

Диатомовые комплексы донных отложений оз. Щучье (Хибинский горный массив, Кольский п-ов)

Fractured basement — an overlooked play type with significant potential from a global seismic database

Fractured basement reservoirs are most commonly defined as metamorphic and igneous rocks unconformably overlain by a sedimentary sequence, where faulting has led to the creation of a natural fracture network where hydrocarbons can accumulate. Here, we also consider basement rocks to include those of sedimentary origin with little or no matrix porosity (North, 1990), such as the Cambro-Ordovician quartzitic sandstones of the Table Mountain group in South Africa. Fractured quartzites and granites are generally considered to be the optimum reservoirs (Koning, 2013). Basement reservoirs have been recognized for decades but are still often disregarded – with wells barely penetrating them – as many oil companies stop drilling as soon as basement rocks are intersected. Where basement has been penetrated to a sufficient depth (approximately 300 m), significant volumes of undiscovered hydrocarbons may still have been missed by a failure to intersect the fracture systems (Aguilera, 1996). Despite inadequate exploration, fractured basement rocks are important oil and gas reservoirs around the globe (Figure 1). Though many were originally found by chance, the large discoveries made in Vietnam and more recently in the UK are now paving the way for an exploration strategy of this unconventional highly prospective play type.

Symboliczne i mityczne góry Kaszubów. Ich rola w kulturze i literaturze kaszubskiej od XIX wieku do okresu międzywojennego

The symbolic and mythical mountains of the Kashubians. Their role in Kashubian culture and literature from the 19th century till the inter-war periodThe geographical location within the Kashubian region is of particular significance for the symbolic role of mountains and hills in the regional identity building. The most important of them, described in the literature and journalistic writings, are to be found in the current Kashubian lan­guage area, mostly in its geographical centre, primarily in Kashubian Switzerland and Kashubian Lake District. The exception is Rowokół, which is not located centrally. This mountain symbolically marks the border of the area in which the Kashubian language is used and which was settled by the Kashubians in the modern period. It even symbolises a retreat of the language as well as the decline of the Slovincian language. However, it is this particular mountain which since the 19th century has been associated with relatively new content mixed with older religious and folk tradition.The mountains and hills appearing in the Kashubian literature in 1880–1930 probably never existed only for themselves and in themselves. They were always part of a broader picture of Kashubia. The contribution offers a typology of four groups of symbolic relevant hills and mountains, accordingly to their function in the Kashubian discourse and tradition: 1. abstract imagination of a “hilly landscape” as typical for the Kashubian country; 2. groups of hills with similar names and connected to similar folklore or literary traditions; 3. unique mountains with special significance for the all-Kashubian discourse; 4. hills as Kashubian places of pilgrimage.

Stable isotope and noble gas constraints on the source and residence time of spring water from the Table Mountain Group Aquifer, Paarl, South Africa and implications for large scale abstraction

Large scale groundwater abstraction is increasingly being used to support large urban centres especially in areas of low rainfall but presents particular challenges in the management and sustainability of the groundwater system. The Table Mountain Group (TMG) Aquifer is one of the largest and most important aquifer systems in South Africa and is currently being considered as an alternative source of potable water for the City of Cape Town, a metropolis of over four million people. The TMG aquifer is a fractured rock aquifer hosted primarily in super mature sandstones, quartzites and quartz arenites. The groundwater naturally emanates from numerous springs throughout the cape region. One set of springs were examined to assess the source and residence time of the spring water. Oxygen and hydrogen isotopes indicate that the spring water has not been subject to evaporation and in combination with Na/Cl ratios implies that recharge to the spring systems is via coastal precipitation. Although rainfall in the Cape is usually modelled on orographic rainfall, δ18O and δ2H values of some rainfall samples are strongly positive indicating a stratiform component as well. Comparing the spring water δ18O and δ2H values with that of local rainfall, indicates that the springs are likely derived from continuous bulk recharge over the immediate hinterland to the springs and not through large and/or heavy downpours. Noble gas concentrations, combined with tritium and radiocarbon activities indicate that the residence time of the TMG groundwater in this area is decadal in age with a probable maximum upper limit of ∼40years. This residence time is probably a reflection of the slow flow rate through the fractured rock aquifer and hence indicates that the interconnectedness of the fractures is the most important factor controlling groundwater flow. The short residence time of the groundwater suggest that recharge to the springs and the Table Mountain Group Aquifer as a whole is vulnerable to climate change and reductions in regional precipitation. Any plans for large scale abstraction to supplement the City of Cape Town water supply would need to factor this into models of maximum sustainable yield.

Sweet vernal grasses (Anthoxanthum) colonized African mountains along two fronts in the Late Pliocene, followed by secondary contact, polyploidization and local extinction in the Pleistocene.

High tropical mountains harbour remarkable and fragmented biodiversity thought to a large degree to have been shaped by multiple dispersals of cold-adapted lineages from remote areas. Few dated phylogenetic/phylogeographic analyses are however available. Here, we address the hypotheses that the sub-Saharan African sweet vernal grasses have a dual colonization history and that lineages of independent origins have established secondary contact. We carried out rangewide sampling across the eastern African high mountains, inferred dated phylogenies from nuclear ribosomal and plastid DNA using Bayesian methods, and performed flow cytometry and AFLP (amplified fragment length polymorphism) analyses. We inferred a single Late Pliocene western Eurasian origin of the eastern African taxa, whose high-ploid populations in one mountain group formed a distinct phylogeographic group and carried plastids that diverged from those of the currently allopatric southern African lineage in the Mid- to Late Pleistocene. We show that Anthoxanthum has an intriguing history in sub-Saharan Africa, including Late Pliocene colonization from southeast and north, followed by secondary contact, hybridization, allopolyploidization and local extinction during one of the last glacial cycles. Our results add to a growing body of evidence showing that isolated tropical high mountain habitats have a dynamic recent history involving niche conservatism and recruitment from remote sources, repeated dispersals, diversification, hybridization and local extinction.

Synthesis of the 780–740 Ma Chuar, Uinta Mountain, and Pahrump (ChUMP) groups, western USA: Implications for Laurentia-wide cratonic marine basins

The upper Tonian Chuar, Uinta Mountain, and middle Pahrump (ChUMP) groups of present-day western Laurentia collectively record the early breakup of Rodinia, large-scale perturbations in the carbon cycle, and eukaryotic evolution, all of which preceded the onset of global glaciation by tens of millions of years. The spectacularly preserved and shale-rich Chuar Group of the Grand Canyon Supergroup stands out as one of the best global records of this time period, particularly for paleobiology. A new U-Pb age of 782 Ma on detrital zircons ( n = 14 young grains) from the underlying Nankoweap Formation refines the Chuar Group’s maximum depositional age to younger than 782 Ma. A new 40 Ar/ 39 Ar age of 764 ± 16 Ma (2σ) from K-feldspar within early diagenetic marcasite nodules from the upper Chuar Group (Awatubi Member) helps calibrate the rich Chuar microfossil record and constrain the large-magnitude shift in δ 13 C org (up to 18‰; referred to here as the Awatubi positive carbon-isotope excursion or APCIE) to between ca. 764 and ca. 742 Ma, the date of an ash near the top of the Chuar Group. In addition to the maximum depositional age of ca. 782 Ma, U-Pb detrital zircon analyses ( n = 826 grains) on sandstone beds from the underlying Nankoweap Formation indicate the presence of multiple older Laurentian age peaks. The similarity of detrital zircon populations and sedimentary character to that of the overlying Chuar Group ( n = 764 grains) suggests that the Nankoweap Formation should be included as the lowermost unit in the Chuar Group. This revised geochronological framework indicates a 300 Ma unconformity between the Chuar Group (including the Nankoweap Formation) and the underlying 1.1 Ga Cardenas Basalt of the Unkar Group. Chuar Group detrital zircon populations share similarities with those of the Uinta Mountain Group and especially the middle Pahrump Group, including ca. 780 Ma grains. Biostratigraphic correlation using microfossils enhances the ChUMP connection and shows a trend of higher acritarch diversity in the lower Chuar and Uinta Mountain groups, and the presence of vase-shaped microfossils in the upper intervals of all three ChUMP units. Comparisons of δ 13 C org and δ 13 C carb among ChUMP successions suggest a combination of local and regional controls. Thus, ChUMP successions are coeval within the 780−740 Ma range, show similar fossil and C-isotope trends, and derived sediments from similar Laurentian sources or source types. In light of recent age constraints and compiled paleontology in other Neoproterozoic basins, our high-resolution correlation of ChUMP successions can be extended to the Callison Lake dolostone of NW Canada and the Akademikerbreen-Polarisbreen groups of Svalbard. Biostratigraphic correlation with poorly age-constrained strata such as the Akademikerbreen-Polarisbreen groups and, farther afield, the Visingso Group of Baltica suggests that ChUMP units record continentwide—and perhaps global—evolutionary patterns. The δ 13 C org and δ 13 C carb values in the Chuar Group and its equivalents in Canada and Svalbard show broadly similar trends, including the APCIE, suggesting that δ 13 C org values from organic-rich shale record variations in the C-isotope composition of late Tonian oceans. Intracratonic basins and contiguous rift margins of ChUMP age are inferred to have been important locations for microbial productivity and significant organic carbon burial that induced large positive shifts in δ 13 C and changes in global carbon balance prior to the onset of snowball Earth.

The hidden hydrology of Groenvlei, a lacustrine wetland on the southern Cape coast of South Africa

Following Parsons’ (2009) challenge of the hypothesis that Groenvlei is sustained by discharge from the underlying Table Mountain Group Aquifer, research was undertaken to better understand the hydrology of Groenvlei. Using a daily water balance model coupled to Darcian flow calculations it was possible to show that direct rainfall and evapotranspiration losses were the key hydrological drivers of the system, with groundwater playing an important but secondary role. It was found that Groenvlei is not endorheic and that S pan measurements are best upscaled to lake evaporation using coefficients offered by Midgley et al. (1994). The reed collar plays an important role in the functioning of the lake, but is dormant during winter. The outcome of the research demonstrated that sound conceptualisation using all available data, information and knowledge remains a critical aspect of any hydrological modelling. The improved understanding of the hydrology of Groenvlei is expected to facilitate a better understanding of the nine Ramsar wetlands located on similar, but more complicated, hydrogeological settings elsewhere on the South African coastline.

Decline of Geladandong Glacier Elevation in Yangtze River’s Source Region: Detection by ICESat and Assessment by Hydroclimatic Data

Several studies have indicated that glaciers in the Qinghai-Tibet plateau are thinning, resulting in reduced water supplies to major rivers such as the Yangtze, Yellow, Lancang, Indus, Ganges, Brahmaputra in China, and south Asia. Three rivers in the upstream of Yangtze River originate from glaciers around the Geladandong snow mountain group in central Tibet. Here we used elevation observations from Ice, Cloud, and land Elevation Satellite (ICESat) and reference elevations from a 3-arc-second digital elevation model (DEM) of Shuttle Radar Terrestrial Mission (SRTM), assisted with Landsat-7 images, to detect glacier elevation changes in the western (A), central (B), and eastern (C) regions of Geladandong. Robust fitting was used to determine rates of glacier elevation changes in regions with dense ICESat data, whereas a new method called rate averaging was employed to find rates in regions of low data density. The rate of elevation change was −0.158 ± 0.066 m·a−1 over 2003–2009 in the entire Geladandong and it was −0.176 ± 0.102 m·a−1 over 2003–2008 in Region C (by robust fitting). The rates in Regions A, B, and C were −0.418 ± 0.322 m·a−1 (2000–2009), −0.432 ± 0.020 m·a−1 (2000–2003), and −0.321 ± 0.139 m·a−1 (2000–2008) (by rate averaging). We used in situ hydroclimatic dataset to assess these negative rates: the glacier thinning was caused by temperature rises around Geladandong, based on the temperature records over 1979–2009, 1957–2013, and 1966–2013 at stations Tuotuohe, Wudaoliang, and Anduo. The thinning Geladandong glaciers led to increased discharges recorded at the river gauge stations Tuotuohe and Chumda over 1956–2012. An unabated Geladandong glacier melting will reduce its long-term water supply to the Yangtze River Basin, causing irreversible socioeconomic consequences and seriously degrading the ecological system of the Yangtze River Basin.

Searching for the glacial refugia ofErebia euryale(Lepidoptera, Nymphalidae) - insights from mtDNA- and nDNA-based phylogeography in the Western Carpathians

The refugial history and postglacial re-colonization routes of Western Carpathian insects are insufficiently understood. Therefore, we investigated the spatio-genetic structure (phylogeography) of Western Carpathian populations of Erebia euryale (Esper, 1805) (Lepidoptera, Nymphalidae) and inferred their colonization routes over the postglacial period. Our results provide new insights into the phylogeography and origin of Erebia euryale in the rarely studied region of the Western Carpathian Mountains. Their phylogeography, including glacial refugia and Pleistocene expansion routes, was reconstructed based on two mitochondrial (COI and CR) and three nuclear markers (CAD, MDH and IDH). Statistical parsimony networks showed the following geographic coherences: (1) populations from Romania and the Bukovske Mountains (Kremenec) grouped together; (2) a Cergov group containing populations only from the Cergov Mountains; (3) a Volovske Mountains group with populations from Kojsovska hoľa and Slovak Paradise grouped together, most likely due to the lack of geographic isolation between the areas; (4) haplotypes characterized from the Volovske Mountains populations were widespread. Comparisons of Western Carpathian E. euryale COI-haplotypes with haplotypes from the Southern Carpathians and Balkans suggest that the refugial areas were located in south-eastern Europe in the Balkan region and Southern Carpathians. We also hypothesize possible central European contact zones in Slovakia for E. euryale in the Western Carpathians. Our results indicate that the Western Carpathians could have served as one of the contact zones between Eastern and Western populations, and additionally as an extra refugium in the southern part of the Volovske Mountains for populations also occurring in Czech mountain regions.

The geological structure of the Muizenberg Block, Cape Peninsula, South Africa

The Muizenberg Block, is an outlier of the Table Mountain Group (Cape Supergroup) and lies to the west of the main occurrence of the Cape Fold Belt. Structural mapping of this outlier has identified a spaced cleavage in Peninsula Formation quartz arenites, and an exposure of dolerite that have not been previously documented. Monoclinal folding, an unrelated spaced cleavage, low-angle faults, and steeply dipping faults, that strike east-northeast – west-southwest, are similar to structures found in the syntaxis domain of the Cape Fold Belt and are therefore thought to have formed during the Late Permian – Early Triassic Cape Orogeny. However, as the Muizenberg Block lies outside the presently accepted boundaries of the syntaxis domain, those boundaries may deserve re-examination. Sub-vertical dilational quartz veining, jointing, cataclastic faulting and the intrusion of a sub-parallel dolerite dyke, that all strike northwest – southeast, are thought to represent a younger tectonic event. They are provisionally attributed to the Upper Jurassic to Cretaceous taphrogenesis that preceded the drifting apart of South America and Africa.

Exploring the different facets of plant endemism in the South-Eastern Carpathians: a manifold approach for the determination of biotic elements, centres and areas of endemism

In the European Alpine System, the Carpathian Mountains are recognized as one of the major centres of diversity and endemism. In the present study, we aimed to explain the spatial structure of plant endemism in its South-Eastern subunit by the complementary use of diversity indices, parsimony analysis of endemicity (PAE), biotic element analysis (BEA), and barrier analysis. We analyzed the available information on 111 plant taxa confined to the South-Eastern Carpathians, mapped using two different sets of operational geographical units (OGUs): 71 geomorphological units and 64 quadrats. Our results showed that centres of endemics diversity largely corresponded to the areas of endemism and biotic elements. PAE consensus cladogram outlined four major areas of endemism (with three nested ones): (1) Danubian; (2) western part of the Southern Carpathians; (3) eastern part of the Southern Carpathians; and (4) Pocutico-Marmarossian. Out of the seven identified biotic elements, five were spatially clustered and overlapped the major areas of endemism, with one notable exception: the calcareous massifs from the Eastern Carpathians, not identified through PAE. Conversely, the latter outlined a nested area of endemism (Cozia – Buila-Vânturarița), omitted by BEA. Barrier analysis identified three major breaks in the distribution of endemics: (1) south of the Retezat – Țarcu – Godeanu mountain group; (2) north of the Piatra Craiului – Bucegi – Ciucaș mountain group; and (3) north of the Rodna massif. The results obtained in here using different methods are generally spatially convergent, indicating highly structured patterns of endemism in the South-Eastern Carpathians. These patterns mostly follow the present-day distribution of alpine habitats and calcareous bedrock, which might have acted as isolating factors through insularity. Interestingly, three of the spatial clusters of OGUs obtained from the endemics distribution analyses (the Eastern Carpathians, as well as eastern and western parts of the Southern Carpathians) largely also correspond to the mid-Miocene archipelago configuration of landmasses in this part of the Carpathians. This might suggest the existence of older migration barriers that emerged throughout the Neogene Period. Differences in the spatial patterns outlined by PAE and BEA could stem from partial sympatry of endemics caused by post-speciation processes such as dispersal or extinction. Additionally, sympatric distribution of taxa with disjunct populations may be caused by the absence of divergence among segregated populations, such as the patterns of relict distributions seen in alpine plants. Finally, the complementary use of these methods may prove to be an efficient approach for better understanding the geographical structure of endemism and provide a starting point for further testing of hypotheses on evolutionary processes.

Preliminary conceptual model of an Alpine carbonate aquifer (Pale di San Martino, Dolomites, Italy)

A hydrogeological and hydrochemical monitoring was conducted in the Pale di San Martino mountain ridge (Trento and Belluno Provinces, Italy) to build a preliminary conceptual model of the groundwater system. The model derives from a combination of new fieldwork and preexisting data provided by various public authorities. New data include geological and hydrogeological surveys, such as in situ measurements of the physical and chemical parameters, geochemical sampling and streamflow measurements. The lithologies outcropping in the area were grouped into seven hydrogeological complexes, each playing a different role in groundwater circulation. The dolomitic body of the ridges forms the main aquifer complex and is located above a terrigenous and evaporitic aquiclude. Due to this geometrical relationship, the site can be considered an isolated hydrostructure with well-defined no-flow boundaries. The main springs outcome near the aquifer-aquiclude boundary and in particular where the elevation of the contact is low and the tectonic pattern favors the drainage. Most of them have a calciumbicarbonate water composition, low temperature and low electrical conductivity, supporting the hypothesis of a fast flowing circulation in carbonate rocks and a high-altitude recharge. Seasonal streamflow measurements allowed the identification of linear springs and provided the first cumulative discharge data at the scale of the entire mountain group. The resulting model highlights a great spatial and temporal variability of the groundwater resources. Considering the geometry of the aquifer and the great seasonal variability of the discharge, it is possible to infer the absence of significant groundwater reserves at a regional scale. Thus, the hydrostructure shows a great capacity to supply water resources (mean discharge of 6 m3/s), but a low selfregulation capacity. It is necessary to consider this aspect when planning a long-term exploitation of the water resources that are used in the area for drinking purposes and hydropower generation.

The karst hydrostructure of the Verzegnis group (NE Italy)

In a quickly changing environment where drinking water appears ever more scarce and polluted, it is vitally important to study the quantity and quality of the available resources. With this in mind, the Verzegnis mountain group (Western Carnian Prealps, NE Italy) represents an important karst aquifer system upon which to draw water to supply inhabitants and industrial activities. The aim of this study is to highlight the state of the art of the resources present in the hydrostructure, understanding the recharge areas and characterizing the flow dynamics with a view to a sustainable exploitation. To complete this study, classical field surveys were conducted during which the main geochemical characteristics were analyzed. Measurements of water temperature (T), Electrical Conductivity (EC), Total Dissolved Solid (TDS), groundwater discharge (Q) and precipitation amount were performed monthly for a period of two years. The geochemical characteristics were defined using water sample analyses of the major ions and δ18O values. The analyses performed and the resulting hydrogeological map allowed for a preliminary characterization of the hydrogeological behavior of the entire hydrostructure where the presence of tectonic structures and different lithological units represent a physical threshold for the waters. In fact, the groundwaters are mainly contained between the tectonic structure Douf—Auda thrust in the E, NE and a permeability threshold on the W created by the presence of the Dolomia di Forni Formation. In the southern side of the massif, a transcurrent fault creates a water divide between Mt. Verzegnis and Mt. Piombada.

Crustal structure beneath the Blue Mountains terranes and cratonic North America, eastern Oregon, and Idaho, from teleseismic receiver functions

AbstractWe present new images of lithospheric structure obtained from P‐to‐S conversions defined by receiver functions at the 85 broadband seismic stations of the EarthScope IDaho‐ORegon experiment. We resolve the crustal thickness beneath the Blue Mountains province and the former western margin of cratonic North America, the geometry of the western Idaho shear zone (WISZ), and the boundary between the Grouse Creek and Farmington provinces. We calculated P‐to‐S receiver functions using the iterative time domain deconvolution method, and we used the H‐k grid search method and common conversion point stacking to image the lithospheric structure. Moho depths beneath the Blue Mountains terranes range from 24 to 34 km, whereas the crust is 32–40 km thick beneath the Idaho batholith and the regions of extended crust of east‐central Idaho. The Blue Mountains group Olds Ferry terrane is characterized by the thinnest crust in the study area, ~24 km thick. There is a clear break in the continuity of the Moho across the WISZ, with depths increasing from 28 km west of the shear zone to 36 km just east of its surface expression. The presence of a strong midcrustal converting interface at ~18 km depth beneath the Idaho batholith extending ~20 km east of the WISZ indicates tectonic wedging in this region. A north striking ~7 km offset in Moho depth, thinning to the east, is present beneath the Lost River Range and Pahsimeroi Valley; we identify this sharp offset as the boundary that juxtaposes the Archean Grouse Creek block with the Paleoproterozoic Farmington zone.

LONG-TERM MONITORING OF GLACIER CHANGE AT GÖSSNITZKEES (AUSTRIA) USING TERRESTRIAL PHOTOGRAMMETRY

Gössnitzkees is a small heavily debris-covered cirque glacier (49.8 ha) located in the Schober Mountains, Hohe Tauern Range, Austrian Alps. Glacier nourishment is mainly due to avalanches descending from its surrounding headwalls. Gössnitzkees is the largest glacier in the Schober Mountains and is highly representative of the other 25 glaciers of this mountain group. All glaciers of this mountain group have receded continuously since 1850. Ongoing atmospheric warming sustains excessive glacier melt. In 1988 a long-term monitoring program was started at Gössnitzkees using terrestrial photogrammetry in order to document and quantify glacier change. The surveys have been repeated from time to time using different types of cameras. Recent surveys date from 2009, 2012, and 2015. The aim of this paper is twofold: firstly, to investigate whether or not the rather complex photogrammetric evaluation process using a conventional photogrammetric workstation (mostly with a limited degree of automation for terrestrial applications) can be replaced by modern fully automated Structure-from-Motion (SfM) based approaches, and secondly, to document and quantify the glacier change at Gössnitzkees based on available information augmented by results obtained from the most recent surveys mentioned. Over the last 27 years (1988-2015) the terminus of Gössnitzkees has receded by 179 m and the glacier ice has melted at a mean annual rate of about 1.5 m/year. The Schober Mountains are in the process of deglaciation and the glaciers will likely disappear within the next two decades. Based on our practical investigations we found out that SfM-based software is in general capable of handling terrestrial photographs in a fully automatic mode supporting challenging glacier studies.

LONG-TERM MONITORING OF GLACIER CHANGE AT GÖSSNITZKEES (AUSTRIA) USING TERRESTRIAL PHOTOGRAMMETRY

Abstract. Gössnitzkees is a small heavily debris-covered cirque glacier (49.8 ha) located in the Schober Mountains, Hohe Tauern Range, Austrian Alps. Glacier nourishment is mainly due to avalanches descending from its surrounding headwalls. Gössnitzkees is the largest glacier in the Schober Mountains and is highly representative of the other 25 glaciers of this mountain group. All glaciers of this mountain group have receded continuously since 1850. Ongoing atmospheric warming sustains excessive glacier melt. In 1988 a long-term monitoring program was started at Gössnitzkees using terrestrial photogrammetry in order to document and quantify glacier change. The surveys have been repeated from time to time using different types of cameras. Recent surveys date from 2009, 2012, and 2015. The aim of this paper is twofold: firstly, to investigate whether or not the rather complex photogrammetric evaluation process using a conventional photogrammetric workstation (mostly with a limited degree of automation for terrestrial applications) can be replaced by modern fully automated Structure-from-Motion (SfM) based approaches, and secondly, to document and quantify the glacier change at Gössnitzkees based on available information augmented by results obtained from the most recent surveys mentioned. Over the last 27 years (1988-2015) the terminus of Gössnitzkees has receded by 179 m and the glacier ice has melted at a mean annual rate of about 1.5 m/year. The Schober Mountains are in the process of deglaciation and the glaciers will likely disappear within the next two decades. Based on our practical investigations we found out that SfM-based software is in general capable of handling terrestrial photographs in a fully automatic mode supporting challenging glacier studies.

Palaeoenvironment and provenance in the early Cape Basin of southwest Gondwana: sedimentology of the Lower Ordovician Piekenierskloof Formation, Cape Supergroup, South Africa

The lowermost unit of the Table Mountain Group (Cape Supergroup), the Ordovician Piekenierskloof Formation is a siliciclastic succession that formed during the initial stages of the Cape Basin development in southwest Gondwana. This contemporary sedimentological re-evaluation of the depositional history and provenance of the Piekenierskloof Formation provides new insights into the palaeoenvironment and tectonic setting of the early Cape Basin. Outcrop-based sedimentary facies analysis revealed distinctive depositional features, dominated by large trough cross-bedding, which suggest a shallow, perennial, sand-bed braided fluvial style with bedload transportation in roughly 1 to 2.5 m deep and relatively wide channels. This fluvial style was possibly influenced by the global absence of substrate stabilizing terrestrial flora in pre-Devonian rivers. Based on an integrated approach of clast count, framework petrography and palaeocurrent studies, the provenance analysis show that the source rocks of the Piekenierskloof Formation were likely situated in source areas characterized by two main rock types: (1) a dominant low metamorphic rank metasedimentary rock suite with parent rocks of variable grain-size, and (2) minor plutonic rocks. The data also suggest that the parent rocks were locally intruded by quartz veins and/or pegmatites. Consistent palaeoflow to the southeast and east further indicates that these source areas were located to the northwest and west of the clastic sediment depocentres in the Cape Basin of southwest Gondwana in the Early Ordovician. Accessible outcrops of the Piekenierskloof Formation are mostly laterally limited and sparsely distributed, which hinder stratigraphic correlations, and therefore inferences of tectonic activity during the sedimentation in the Early Ordovician cannot be convincingly made. For a better understanding of the Early Palaeozoic evolution of the Cape Basin in southwest Gondwana, systematic outcrop studies acquiring high-resolution digital imagery using unmanned aerial vehicles (UAVs) and terrestrial laser scanning, coupled with subsurface facies analysis should be undertaken. The Piekenierskloof Formation and the rest of the Table Mountain Group, with their exceptionally extensive, but rather inaccessible cliff faces, are excellent candidates for such high-resolution digital-based studies.

Evaluation Exhaustive De La Diversité Des Plantes Aromatiques Et Médicinales De La Péninsule Tingitane (Maroc)

Aromatic and Medicinal Plants (AMP) represent a large part of biodiversity. However, in the absence of a detailed record of this diversity, research and AMP development projects are generally limited to a small portion of ethnobotanical heritage. To guide prospection, exploitation and conservation studies of the existing potential, a comprehensive evaluation of the natural diversity of AMP is required. The western Rif region in northern Morocco, which area represents less than 1% of national territory, is home to about 50% of the Moroccan floristic richness (2053 species and infraspecific taxa). This heritage includes 630 taxa from which only 23 are currently exploited and merely 57% are recognized by ethno-botanists. Among these assets, a list is drawn up containing 106 taxa with a special conservation status (very rare or rare taxa, and / or endemic and / or threatened) and some of which are widely exploited. From a phytosociological point of view and based on an available database of 449 floristic samples, natural forest stands and matorrals contain about 27% of all MAP of the study area. These AMP organize almost half the floristic composition of sclerophyllous forests (oleaster, kermes oak and cork oak forest) and about a third of the richness of each of the other groups analyzed (thermophilic formations, pure fir, limestone mountains forest, calcifuges deciduous, maritime pine, matorrals). Mountain groups are the richest in exclusive, endemic, rare and endangered AMP.