Dolomite Outcrops Research Articles

Seismic imaging of the gold deposit and geological structures through reprocessing of legacy seismic profiles near Kloof–Driefontein Complex East Mine, South Africa

AbstractTwo legacy reflection seismic profiles were acquired in 1988, north of the Kloof–Driefontein Complex East Mine in the West Rand goldfield (South Africa), for the purpose of gold exploration and mine planning. These legacy 2D seismic data have been reprocessed using the latest processing tools to improve imaging. Special interest is given to the Black Reef Formation, which hosts a known gold orebody. The original legacy data are of poor quality, especially in areas that are dominated by dolomitic outcrops. To improve the quality of the data, special attention was given to the refraction static correction to enhance the continuity of the reflections below dolomitic rocks. Refraction seismic tomograms from both profiles exhibit three‐layer P‐wave velocity models: (1) topsoil (1000–2000 m/s), (2) a weathered layer ranging from ca. 100 to 300 m in thickness (2000–5000 m/s) and (3) bedrock (> 5000 m/s). Seismic profile OK‐212 shows poor imaging of the Black Reef Formation because of the scattering of seismic energy in the near‐surface due to dolomites from the Transvaal Supergroup, while seismic profile OK‐213 exhibits south‐dipping reflections that are associated with the Black Reef Formation. To improve the structural imaging resolution, we tried pre‐stack time migration, pre‐stack depth migration and post‐stack time migration using the Kirchhoff algorithm. PreSDM most improved the imaging of deeper reflections due to its ability to honour complex lateral variations in the velocity field. Both pre‐stack time migration and post‐stack time migration enhanced the continuity of the near‐surface reflections below the dolomitic rocks.

Chemical evolution of runoff in Eastern Mediterranean mountainous karstic terrains

The Israeli central mountain rim was chosen to represent the transformation of rain chemical composition to runoff composition in a carbonate landscape under a Mediterranean climate. It was found that at the mostly dolomitic slopes of the Samaria Mountains the main processes shaping runoff chemistry are dissolution of dry fallout (dust) and salts that were precipitated during evaporation of water from previous small-scale runoff events. Calcium and sulfate concentrations in the runoff are defined mainly by the dissolution of dust minerals. The main input of sodium and chloride into runoff composition comes from both rain and dissolution of halite that remained from the evaporation of the previous runoff, whereas the main input of magnesium is connected to dissolution of dolomite outcrops. A combination of forward and inverse modeling by using PHREEQC software was found to be effective for studying runoff chemistry formation. Numerical simulations of runoff sample evaporation have shown that the main minerals precipitating during dry periods are calcite, anhydrite/gypsum, glauberite and halite. The high Na to Cl equivalent ratios (about 1.3 at average) may reflect two-phase dissolution of sulfates and halite in the initial stage that whereas and of glauberite in the following stage. Rainwater transformation to runoff inverse modeling was found to be consistent with the results of forward modeling, confirming these runoff chemical processes.

Physicochemical Characterization of the Quality of Groundwater: Case Study of the Tebessa Plain (North-East Algeria)

In order to characterize the physicochemical quality of groundwater, and to examine the behavior of factors influencing water chemism in the Tebessa Plain, which is part of a semi-arid region located in the northeast of Algeria, physicochemical analyses were carried out on 32 water samples from the Mio-Plio quaternary water table. In the east of the study region, in the Djebissa area, most of the Triassic formations form a depression made up of masses of gypsiferous clay, where some outcrops of Triassic dolomites appear together with several blocks of carbonate rocks, torn off during the Aptian- Albian age. In the center and to the west of the plain, carbonate formations are represented by a significant layer of limestone marl and marl from the Cretaceous to Tertiary periods. The results obtained showed that the quality of the water is influenced by the heterogeneity of the geological formations. The concentrations of chlorides, sulphates, and sodium are high in the eastern part of the study area, which can be explained by the impact of gypsum formations, confirmed by the Sr<sup>2+</sup>/Ca<sup>2+</sup> ratio being greater than 3 ‰ for the majority of samples. In the wells of the Tebessa and Ain Chabro areas, the concentrations of calcium, magnesium, and bicarbonates increase due to the predominance of carbonate formations of borders. The use of the statistical tool confirmed the evaporitic origin of the anions, especially in the east of the study region.

Vegetation and flora of marble outcrops and their nearby matrices in mountains of central Argentina. Rock chemistry also matters

We present a comparative study of the flora and vegetation of marble outcrops and their nearby migmatite matrix from mountains in central Argentina. In all, we sampled 50 sites and recorded the cover-abundance of all vascular plants present according to the Braun-Blanquet cover-abundance scale. In addition, rock fragments were collected for chemical analysis (Ca2+, Mg2+, K and Na). Three plant communities were classified using ISOPAM, one occurring in the migmatite matrix and two others associated with calcic (richer in Ca2+) and dolomitic (richer in Mg2+) marble, respectively. The marble outcrops and nearby matrix vegetation differed in plant species and life form composition, as well as in diagnostic species. Rocky outcrops also exhibited differences in floristic composition between dolomitic and calcic marble. The overall number of species in the matrix vegetation was higher than in the outcrop communities, but dolomitic outcrops revealed a higher average species richness per relevé. We found a higher proportion of endemics in the marble vegetation with respect to the surrounding matrix communities, with herbs, grasses and subshrubs dominating in the marble outcrops, while trees and shrubs dominated the matrix vegetation. Taxa of the Southern-Brazilian and Chaquenian chorotypes were the most abundant in the three communities. Our results suggest that the marble outcrops harbor a flora including several highly restricted endemics, which is clearly distinct from that of the surrounding habitats, indicating that outcrop diversity should be taken into account in conservation policies.

Middle Stone Age lithic assemblages from Leba Cave (Southwest Angola)

Africa is a key region to understand the emergence and evolution of humans and their distinctive cultural traits. Detailed information exists across the continent, but major areas still lack crucial evidence. One of the most under-represented regions in research about the Middle Stone Age (MSA) is Angola. The geographical position of Angola linking the Central Plateau of Africa to the rainforest, at north, and the Namib Desert, at south, encompasses a mosaic of ecotones that are most relevant to understand the emergence and evolution of human culture in Southwestern Africa.A detailed analysis of the lithic assemblages from Leba Cave, a site located in the western edge of the Huíla Plateau is presented. These highlands correspond to a strip of the Great Escarpment of Africa, a major landform shaping the relief of the southern half of the continent. In the upper series of the escarpment in southern Angola, the outcrops of dolomites and dolostones present a variety of karstic features with preservation of palaeontological and archaeological remains.Leba Cave is located at Humpata, Huíla Province, and was discovered during the Portuguese Colonial Missions. A test pit opened in 1950 retrieved a collection of sediments, fauna and lithics. Our study was focused on the lithic assemblages referenced with the three lower horizons in the reported stratigraphy (III, IV, VI). The techno-typological analysis of the lithics showed these assemblages relate to the classic repertoires of the MSA found across Southern and Central Africa. The chrono-cultural significance of these results is discussed, as well as the regional idiosyncrasies that may characterize the lithic assemblages north of the Namib Desert.

Intracellular and Extracellular Biomineralization Induced by Klebsiella pneumoniae LH1 Isolated from Dolomites

The interaction between bacteria and minerals is very complicated and has been intensively studied in the laboratory and the field in the last few decades, but the processes and mechanisms of biomineralization and mineral precipitation are still not fully understood and need to be explored further. In the present work, biomineralization experiments were undertaken using Klebsiella pneumoniae LH1, collected from a natural surface environment in an area of outcrops of Cambrian dolomite, in a culture medium with various Mg/Ca molar ratios (0, 3, 6 and 12). The mineral precipitates obtained were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectrometer (FTIR), laser scanning confocal microscopy (LSCM) and X-ray photoelectron spectroscopy (XPS). Cells were analyzed with a scanning transmission electron microscope (STEM), high resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED). The composition of amino acids in extracellular polymeric substances (EPS) was also determined. In the experiments it was found that the production of ammonia and the presence of carbonate anhydrase promoted the increase of the medium pH and that minerals are nucleated on the EPS, which consist chiefly of amino acids and negatively-charged organic functional groups. With increasing Mg/Ca ratios, the mineral phases changed, including calcite (100%) at Mg/Ca molar ratio of 0, monohydrocalcite (36.05%) + dypingite (63.95%) at Mg/Ca molar ratio of 3, monohydrocalcite (29.72%) + dypingite (15.48%) + nesquehonite (54.80%) at Mg/Ca molar ratio of 6, and monohydrocalcite (14.2%) + dypingite (1.0%) + nesquehonite (84.80%) at Mg/Ca molar ratio of 12. Some intracellular amorphous calcium- and magnesium-rich inclusions were also detected in K. pneumoniae LH1, suggesting intracellular biomineralization accompanying the extracellular mineral precipitation. This study provides further understanding of the biomineralization processes of microorganisms.

Bed‐scale spatial patterns in dolomite abundance: Part II. Effect of varied fluid chemistry, flow rate, precursor mineralogy, temperature, textural heterogeneity, nucleation density and bed geometry

AbstractReaction‐transport modelling shows that a lateral, metre‐scale pattern in dolomite abundance can form during replacive dolomitization of calcite and aragonite precursors by Mississippian, Triassic and modern seawaters advecting at >20 cm year−1 in low temperature (≤60°C) hydrogeological systems. The modelled pattern develops best in beds >1 m thick with a relatively uniform nucleate density and a low variance in reactive surface area (for example, grainstones). These conditions suggest that a lateral pattern in dolomite abundance should be expected in dolomites formed by any shallow hydrodynamic system that advects dolomitizing fluid horizontally, including the down‐gradient portion of a reflux system, the oceanward reaches of geothermal (Kohout) convection systems, and the seaward reaches of a seawater entrainment zone below a freshwater aquifer. However, even in those systems, a pattern will not form in all dolomites. Pattern will be muted in thinner (≤ ca 50 cm thick) beds and non‐emergent where the precursor had a high variance in reactive surface area (for example, a skeletal wackestone) and/or large variation in nucleate density. Pattern also did not form at temperatures above ca 60°C, which implies that pattern should not be expected in dolomites formed at intermediate to deep burial depths. As the patterns are horizontal, they also should not be expected where dolomitizing fluids moved vertically (for example, reflux immediately below a brine source). Pattern metrics (short‐range correlation length, and wavelength and amplitude of the longer cyclic component) vary with flow rate, fluid chemistry, bed thickness, porosity, grain size, temperature and the flow complexity (one‐dimensional, two‐dimensional or three‐dimensional) within the bed. However, no modelled pattern produced metrics larger than those documented on dolomite outcrops. The results thus constrain the length scales of porosity and permeability variance to include in petrophysical models of dolomite reservoirs, as well as the geological scenarios in which to consider metre‐scale lateral petrophysical variability.

Genetic diversity and differentiation in narrow versus widespread taxa of Helianthemum (Cistaceae) in a hotspot: The role of geographic range, habitat, and reproductive traits.

Unraveling the relationships between ecological, functional traits and genetic diversity of narrow endemic plants provide opportunities for understanding how evolutionary processes operate over local spatial scales and ultimately how diversity is created and maintained. To explore these aspects in Sierra Nevada, the core of the Mediterranean Betic‐Rifean hotspot, we have analyzed nuclear DNA microsatellite diversity and a set of biological and environmental factors (physicochemical soil parameters, floral traits, and community composition) in two strictly endemic taxa from dolomite outcrops of Sierra Nevada (Helianthemum pannosum and H. apenninum subsp. estevei) and two congeneric widespread taxa (H. cinereum subsp. rotundifolium and H. apenninum subsp. apenninum) that further belong to two different lineages (subgenera) of Helianthemum. We obtained rather unexpected results contrasting with the theory: (a) The narrow endemic taxa showed higher values of genetic diversity as well as higher average values of pollen production per flower and pollen‐to‐ovule ratio than their widespread relatives; and (b) the two taxa of subg. Helianthemum, with larger corollas, approach herkogamy and higher pollen production than the two taxa of subg. Plectolobum, displayed lower genetic diversity and higher values of inbreeding. Altogether, these results disclose how genetic diversity may be affected simultaneously by a large number of intrinsic and extrinsic factors, especially in Pleistocene glacial refugia in mountains where the spatial context harbors a great ecological heterogeneity. On the other hand, differences in mating system and the significant effect of the substrate profile, both being highly diverse in the genus Helianthemum, in the genetic variability illustrate about the importance of these two factors in the diversification and species differentiation of this paradigmatic genus in the Mediterranean and open the field to formulate and test new hypotheses of local adaptation, trait evolution, and habitat diversification.

Fracture distribution on the Swift Reservoir Anticline, Montana: Implications for structural and lithological controls on fracture intensity

Abstract Where primary porosity and permeability of a rock are unfavourable for hydrocarbon production, fractures can improve reservoir potential by enhancing permeability. Higher fracture intensity may create a better-connected fracture network, improving fractured-reservoir quality. Investigations into the controls on fracture intensity commonly conclude that either structural or lithological factors have the greatest influence on fracture abundance. We use the Swift Reservoir Anticline in northwestern Montana to investigate how fracture intensity varies throughout the structure and determine that although structural factors do influence fracture intensity, lithology is the main control at outcrop. The Swift Reservoir Anticline exposes bedding surfaces of the Mississippian Castle Reef Formation dolomite. Field data indicates that fracture intensity is highest in the fold forelimb, decreasing into the backlimb except in outcrops of coarse dolomite where fracture intensity is low, regardless of structural position. Field fracture intensity correlates with whole-rock quartz, kaolinite and porosity percentages. We suggest porosity and composition influence bulk-rock mechanical properties, which, in turn, control the fracture intensity at outcrop. Fracture intensity has a stronger relationship with lithological than structural factors, therefore we suggest that the key to predicting fracture intensity in the subsurface here is understanding how lithology varies spatially.

FRACTAL ANALYSIS OF FRACTURE SYSTEMS IN UPPER TRIASSIC DOLOMITES IN ŽUMBERAK MOUNTAIN, CROATIA

This paper presents results of fractal analysis of fracture systems in upper Triassic dolomites in Žumberak Mountain, Croatia. Mechanical rock characteristics together with structural and diagenetic processes results with fracture systems that can be considered as fractals. They are scale-invariant in specific range of scales. Distribution of fractures can be than described with power law distribution and fractal dimension. Fractal dimension is a measure of how fractures fill the space. Fractal dimension can be estimated form photographs of outcrops by converting photographs to binary photographs. In binary photo there is only black (rock or fractures) and white (fractures or rock). Fractal dimension is then estimated based on box-counting method. In this paper we present results of fractal analysis from three outcrops. Results are very similar to previous published results from outcrops of dolomites in Slovenia. Obtained fractal dimensions are in range 2,69-2,78 and it depends on how fracture systems are distributed in the outcrop. Lower values indicate smaller number of fractures and higher significance of larger fractures. Higher values indicate distribution of more similar sized fractures throughout whole outcrop. Fractal dimension is very significant parameter in rock fracture system characterisation sense it describes how fractures are distributed in the outcrop. It can be used in discrete fracture network modelling if spatial distribution of fractures is represented with power law distribution.

New Records of Lichens and Lichenicolous Fungi in Lithuania, Mainly from Quarries

Motiejūnaitė, J. & Skridlaitė, G. 2017. New records of lichens and lichenicolous fungi in Lithuania, mainly from quarries. — Herzogia 30: 126–137.The lichen floras of dolomite, limestone, opoka, clay, sand and gravel quarries, as well the few existing natural dolomite outcrops suitable for lichens in various parts of Lithuania were studied. Also, some lichen records from built-up areas were examined. Quarries and built-up areas proved to be habitats rich in lichens, harbouring a number of rare species, two of which, Lecania leprosa and Stigmidium collematis, are new for the whole Baltic Sea region, and Caloplaca soralifera, Hawksworthiana peltigericola and Skyttella mulleri are recorded for the first time in the Baltic States. Seven lichens, Blennothallia crispa, Dirina massiliensis f. sorediata, Gregorella humida, Hymenelia epulotica, Protoblastenia rupestris, Psoroglaena dictyospora and Thelidium incavatum and two lichenicolous fungi, Didymellopsis pulposi and Stigmidium peltideae, are new for Lithuania. Ecology and conservation issues of rare calcicolous lichens in the country are discussed, and it is noted that transient type of their habitats and the habitat management make lichen protection unfeasible.

Ubicazione delle cave di pietra da calce utilizzata come materia prima degli intonaci romani nella Lombardia occidentale

[it] La calce come materiale da costruzione ebbe larga diffusione nell’architettura romana della Lombardia occidentale. La presenza di carbonato di magnesio è stata per lo più riscontrata negli intonaci dipinti provenienti dai siti romani di Milano. Il carbonato di magnesio testimonia l’impiego di dolomia per la preparazione della calce e rocce di questa composizione affiorano per esteso nelle Prealpi lombarde: dolomie e calcari dolomitici grigio chiari (Dolomia del Salvatore, Ladinico-Anisico), dolomie grigie, talvolta con ciclotemi (Dolomia principale, Norico). Non sono conservate evidenze di cave o di forni romani in quest’area prealpina: i Romani sfruttarono gli stessi affioramenti dolomitici, situati lungo la sponda orientale del lago Maggiore, affioramenti da cui si produsse calce a partire dal Medio Evo in avanti. 
 I depositi fluvio-glaciali del medio corso del fiume Adda tra Brivio e Trezzo (massi, ciottoli di calcari marnosi, calcari e dolomie che affiorano nel bacino fluviale) furono un’altra fonte medievale e moderna di materia prima, soprattutto per produrre una calce debolmente idraulica (chiamata “calce forte”), ma questo tipo di calce è assente negli intonaci romani.

Delimiting plant diversity that is functionally related via interactions with diurnal pollinators: An expanded use of rarefaction curves

The way in which taxonomic diversity relates to functional diversity is important for understanding the mechanisms that sustain ecosystem function and services. We investigated how an explicit consideration of plant-pollinator interactions influences our view of plant diversity. We studied three plant species-rich communities located in different biodiversity hotspot regions: two soil-specific plant communities with Mediterranean-climate, sandy dolomite outcrops in Andalusia (Spain) and serpentine seeps in California (USA), and a third community in the sub-tropical dry scrublands in Yucatan (Mexico). Sampling at three spatial scales (region, site, plot) and rarefaction analyses were used to characterize and compare spatial and temporal variation of entomophilous plant diversity based on species presence (“static plant diversity”), flower display sizes along the season (“dynamic flower diversity”), and pollinator visitation (“interaction-effective diversity”). The studied communities differed in the static diversity of plants, with sub-tropical dry scrublands being less diverse than the two Mediterranean communities. Reduction of static diversity at local scale was stronger in the richest Mediterranean communities and, thus, static diversity was similar among regions when considering finer (site-level) spatial scales. In addition, the two Mediterranean communities displayed more seasonal variation, thus reducing differences in dynamic diversity among regions, i.e. when considering finer temporal scales. These results suggested that, at finer spatio-temporal scales expected to be relevant for interactions with pollinators, plant communities are not necessarily as diverse as the region where they occur. Accordingly, interaction-effective diversity based on pollinator visitation was in all cases lower than expected relative to the diversity of flowers. Thus, diversity of visited flowers does not perfectly track diversity of flowering species but instead reaches asymptotes at much lower values than expected in the richest communities. Regional species diversity may support the functionality of interactions at broader spatial and temporal scales than they actually occur.

Visualization of Acid Treatments With 3D Nuclear-Magnetic-Resonance Imaging

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 168198, “The First Visualization of Acid Treatments on Carbonates With 3D Nuclear-Magnetic-Resonance Imaging,” by M. Krebs, SPE, Clausthal University of Technology; B. Lungwitz, SPE, A. Souza, SPE, A. Pépin, SPE, S. Montoya, P. Schlicht, and A. Boyd, SPE, Schlumberger; and E. Vidoto, R. Polli, and T. Bonagamba, University of Sao Paulo, prepared for the 2014 SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 26–28 February. The paper has been peer reviewed and is scheduled to appear in SPE Journal. Core-flow tests are usually conducted to test and model stimulation treatments at laboratory scale, to predict the performance of such treatments in carbonate reservoirs. The visualization of wormholes created within core-flow tests requires novel technologies for evaluation and pathway-prediction purposes. Unfortunately, past visualization techniques were always associated with the destruction of the core sample. This paper describes the use of nuclear-magnetic-resonance imaging (NMRI) as a nondestructive visualization method in correlation with 3D rock imaging. Introduction The experiments described in the complete paper were conducted with different core samples such as Indiana limestone, Silurian dolomite, Winterset limestone, and carbonate outcrops. The core samples were selected according to their properties, which greatly differ for each type with respect to their origin. The core-flow tests or acidizing tests performed in this study serve the purpose of simulating field treatments at laboratory scale. NMRI applies a gradient static magnetic field such that the strength of the field decreases with increasing distance away from the source. The Larmor frequency becomes dependent on the position of the nuclei, which will be associated with a single value of the gradient magnetic field. Hence, it is possible to locate the nuclei in a region radially around the source. More specifically, NMRI uses mostly pulsed gradient magnetic fields that belong to a group of linear gradient fields in order to link acquired signals to a specific volume element. Therefore, it is possible to locate the nuclei more exactly in the 3D space instead of only defining a region. The gradient fields are used for spatial encoding to acquire a location-dependent signal, and they are the slice-selection gradient, phase-encoding gradient, and frequency-encoding gradient.

Variability, genetic structure and phylogeography of the dolomitophilous speciesConvolvulus boissieri(Convolvulaceae) in the Baetic ranges, inferred from AFLPs, plastid DNA and ITS sequences

Convolvulus boissieri is an edaphic endemic plant which grows in the Baetic ranges always in association with high mountain xeric dolomitic outcrops. As these dolomitic areas appear in a ‘soil-island’ pattern, the distribution of this species is disjunct. Populations of this species frequently include a low number of individuals, which could have an important impact on their genetic diversity and viability. Convolvulus boissieri provides an excellent opportunity to study the genetic and phylogeographical aspects of species linked to dolomites. We used amplified fragment length polymorphism markers and nuclear (internal transcribed spacer region of the nuclear ribosomal cistron) and plastid sequences (trnL-trnF, rpl32-trnL and trnQ-5′rps16). Data were generated from 15 populations, representing the distribution area of the species. For sequence analysis and estimation of divergence times we also used sequences from other Convolvulus species. Results revealed low intrapopulational genetic diversity and a strong interpopulational structure. Furthermore, we found clear-cut differentiation caused by the existence of two large population groups separated by the Guadiana Menor river basin. Estimation of divergence times indicated that divergence took place during the Pleistocene glaciations. Genetic diversity and differentiation are similar to those other species exhibiting naturally fragmented distribution with a sky islands pattern. In phylogeographical terms, the successive glaciation–interglaciation cycles caused the species to spread from the western sites to eastern sites, the latter being more exposed to the effects of glaciation. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 506–523.

Seasonal variations in leaf δ13C values: implications for different water-use strategies among species growing on continuous dolomite outcrops in subtropical China

Plant species growing in shallow-soil habitat are likely to experience water deficit especially in seasonally dry or arid regions. However, only scarce studies focused on their water-use strategies. The current study aimed to reveal water-use strategies of different species growing on continuous dolomite outcrops (a typical shallow-soil habitat) in subtropical China that relied on different water sources, and to investigate the differences between narrow endemic and widespread species, based on season variations in leaf δ13C values. Leaf samples of six plant species (Radermachera sinica, Sapium rotundifolium, Sterculia euosma, Schefflera octophylla, Alchornea trewioides, and Vitex negundo, in different life-forms and leaf phenologies) were collected for carbon isotope measurements in the wet and dry seasons, respectively. Contrary to the expectation, the evergreen big shrub species, S. octophylla, which always relied on deep water sources, exhibited the most positive δ13C values (high water-use efficiency, WUE), indicating more conservative water-use strategies. While the two deciduous small shrubs, A. trewioides and V. negundo, which always relied on shallow water sources, exhibited the most negative δ13C values (low WUE). This result was associated with their short life spans, indicating an opportunistic water-use strategy. Leaf δ13C values of almost all (except for S. octophylla) the selected species were significantly (P < 0.05) higher in the dry season than in the wet season. This indicated that it was a common strategy for species in rocky karst habitat to improve their WUE in dry season. Despite the similar water sources utilized by the selected three tree species, the widespread one (R. sinica) exhibited greater improvement in leaf δ13C values than the narrow endemic ones (S. rotundifolium and S. euosma). This suggested that the widespread tree species had more flexible water-use strategies. It was further speculated that broad spatial distribution of widespread species may contribute to their highly plastic responses to changes in environmental conditions rather than always maintaining high WUE.

Airborne geophysical survey of the catastrophic landslide at Stože, Log pod Mangrtom, as a test of an innovative approach for landslide mapping in steep alpine terrains

Abstract. Airborne geophysics is a promising method for investigating landslides. Here we present a case study of multisensor airborne geophysical survey at the catastrophic landslide Stože near Log pod Mangrtom in Slovenia, which was conducted in the framework of the European FP7th Project "SafeLand". Based on the survey itself and achieved results, we discuss applicability, limits, and benefits and costs of the method for investigating landslides in steep alpine terrains. Despite of several operational constraints, the airborne electromagnetic survey of the area well presented the lithological pattern and water saturation. The high resistivity regions mostly indicated drained slope scree and landslide mass, drained and loosened material of the moraine deposit in the tension zone of the landslide with present cracks and cavities. The minima of the resistivity pattern were attributed to the outcrop of marls rich in clay, to water-saturated moraine deposit above impermeable marls in the tension zone, and to water-saturated porous alluvial gravel and landslide scree along the Koritnica River. The magnetic survey proved to be inapplicable for such a small and rough area. The Potassium and Thorium maps, on the other hand, both well identified the regions of tension inside the landslide zone, outcrops of marls and dolomite, clay-rich colluvium, weathered zones along a regional tectonic fault, and alluvial deposits and deposits of debris flows, and the minima of the 137Cs clearly revealed the zones of material removal due to recent mass movements.

Strong inbreeding depression and individually variable mating system in the narrow endemic &lt;i&gt;Erodium cazorlanum&lt;/i&gt; (Geraniaceae)

Alonso, C. & Garcia-Sevilla, M. 2013. Strong inbreeding depression and individually variable mating system in the narrow endemic Erodium cazorlanum (Geraniaceae). Anales Jard. Bot. Madrid 70(1): 72-80. Angiosperms evolved different systems to attract effective pollinators while reducing selfing in hermaphroditic flowers. Selfing ability can be advantageous when pollinators and/or mates are scarce, although inbreeding depression may largely reduce those advantages. Recent comparative analyses suggested endemic species tend to evolve self-compatibility but a better understanding of the associated reproductive and genetic tradeoffs is required. Experimental hand-pollinations under greenhouse conditions were conducted to investigate the selfing ability and estimate inbreeding depression up to the offspring’ first reproductive event in Ero dium cazorlanum, a narrow endemic species restricted to dolomite outcrops in SE Spanish mountains. We found autonomous selfing ineffective. Further, when experimentally applied, pollen of the same flower produced significantly fewer fruits and seeds compared to geitonogamous and cross pollinations. The number of seeds per fruit was significantly higher after cross pollinations and strong inbreeding depression accumulated through the life-cycle. Interestingly, individual plants exhibited broad variation in selfing ability with six out of 14 individuals producing no seed after geitonogamy. Understanding the consequences of individual variation in self compatibility deserves further investigation in the field now that we know that strong inbreeding depression may limit recruitment of selfed progeny.

Water source utilization by woody plants growing on dolomite outcrops and nearby soils during dry seasons in karst region of Southwest China

Summary In the seasonally dry karst region of Southwest China, woodland vegetation is frequently associated with rocky outcrops. We used stable isotope techniques to determine the water sources of two woody plant species (the semideciduous tree Rademachera sinica and the deciduous shrub Alchornea trewioides ) across three surface types: continuous and isolated dolomite outcrops, as well as adjacent surfaces with soils. Main water sources for R. sinica growing on the continuous outcrops shifted from deep water sources (e.g., water in the saturated zone) on March 23, 2009 (the late dry season of 2008–2009) to rainwater stored in rock fissures of the unsaturated zone on November 8, 2009 (the early dry season of 2009–2010). R. sinica growing on nearby thin soils exhibited a similar shift of main water sources, from deep water sources in the late dry season to shallow soil water (0–30 cm) in the early dry season. However, they extracted deep water sources from the bottom of nearby outcrops rather than from deeper layers below the soil surface. Main water sources for R. sinica growing on the isolated outcrops shifted from previous (one to two months ago) rainwater in the late dry season to the mixture of recent (within the last one month) and previous rainwater in the early dry season, while using little or no deep water sources. In contrast, A. trewioides growing on these two kinds of outcrops always relied on recent rainwater, while those growing on soils always relied on shallow soil water. The shift of water sources for tree species (especially those growing on continuous rock outcrops and nearby soils) may allow them to maintain normal transpiration throughout the year, which increases the amount of evapotranspiration in the watershed and further enhances the water storage capacity of the study area.

キレート滴定の諸問題と, 石灰石, ドロマイト露頭における化学成分の変動について

キレート滴定の諸問題と, 石灰石, ドロマイト露頭における化学成分の変動について