Observations of rotational motion in prominences

The writer reports some recent observations carried out with the McMath Solar Telescope, which can be interpreted as due to rotational motions in prominences. Kitt Peak National Observatory Contribution No. 454. Visiting Astronomer to the Solar Division, Kitt Peak National Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation.     

Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land,South Africa

A Paleoarchean impact spherule‐bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro‐X‐ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer‐scale, assisted in the localization and characterization of eight spherule‐bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni‐Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al₂O₃‐rich and can be distinguished from the Al₂O₃‐poor marine sediments by distinct Al‐OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al‐OH‐rich spherule layers in Al₂O₃‐poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism.     

Novel applications of fluid inclusions and isotope geochemistry in unravelling the genesis of fossil travertine systems

The Denizli Basin is a fault‐bounded Neogene–Quaternary depression located in the Western Anatolian Extensional Province, Western Turkey. The basin is a unique geological site with abundant active and fossil (Quaternary) travertine and tufa deposits. Fluid inclusion microthermometry and isotopic analysis were applied to study the genesis of the Ball?k fossil travertine deposits, located in the south‐eastern part of the basin. Microthermometry on fluid inclusions indicates that the main travertine precipitating and cementing fluids are characterized by low salinity (<0·7 wt% NaCl equivalent) and variable temperatures that cluster at <50°C and ca 100°C. Fluids of meteoric origin have been heated by migration to the deeper subsurface, possibly in a local high geothermal gradient setting. A later uncommon cementation phase is related to a fluid with a significantly higher salinity (25·5 to 26·0 wt% bulk). The fluid obtained its salinity by interaction with Late Triassic evaporite layers. Strontium isotopes indicate that the parent carbonate source rock of the different travertine precipitates is very likely to be the Triassic limestone of the Lycian Nappes. Carbon isotopes suggest that the parent CO₂ gas originated from thermal decarbonation of the Lycian limestones with minor contributions of magmatic degassing and organic soil CO₂. Oxygen isotopes confirm the meteoric origin of the fluids and indicate disequilibrium precipitation because of evaporation and degassing. Results were integrated within the available geological data of the Denizli Basin in a generalized travertine precipitation model, which enhanced the understanding of fossil travertine systems. The study highlights the novel application of fluid inclusion research in unravelling the genesis of continental carbonates and provides several recommendations for hydrocarbon exploration in travertine‐bearing sedimentary basins. The findings suggest that travertine bodies and their parent carbonate source rocks have the potential to constitute interesting subsurface hydrocarbon reservoirs.     

Kinematics of a twisted surge

Using the H-alpha solar filtergrams taken at Kandilli Observatory, we have studied the motion of a twisted surge, from the kinematic point of view. We applied the Palu (1972) method to two knots of the twisted surge occurred at 10 November, 1967. The results are discussed.     

Geochemistry, mineralogy and genesis of pyrophyllite deposits in the Pötürge Region (Malatya, Eastern Turkey)

In the Pötürge (Malatya, Turkey) area pyrophyllite occurrences are common in the shear zones, mostly in the form of lenses along faults. Mineralogical investigations (XRD, FTIR and SEM) revealed that pyrophyllite, kaolinite (dickite) and quartz are present in the form of major phases and muscovite (sericite), kyanite, chlorite, and alunite are only present in the form of minor phases. This study revealed that the existence of the kyanite phase points out to high pressure and temperature conditions which the rocks were underwent. On the other hand, the minerals such as pyrophyllite, kaolinite, and alunite are products of a low degree metamorphism (retrograde). The mineral paragenesis in the pyrophyllite deposits suggests that the formation of minerals took place in two ways: (1) the transformation of kyanite into pyrophyllite and quartz through retrograde metamorphism by a high degree temperature, (2) then pyrophyllite and probably muscovite were transformed into kaolinite and alunite through reactions with relatively low temperature hydrothermal fluids. The geochemical data indicate that during the retrograde metamorphism the elements K, Rb, Sr, Ba, S, and Fe were mobile, the elements Si, Al, P moderately mobile to immobile and the HPS elements (Zr, Ti, and Nb) were immobile. It was shown that the formation of pyrophyllite, kaolinite and alunite was associated with depletion in alkalis, Mg, Fe and enrichment of elements including Sr, Ba, and S. Mineralogical and geochemical data suggest that parent rocks (pre-metamorphism) of the Pötürge pyrophyllite were probably kaolinite, Al-rich clays or bauxites.     

Degradation of digested sewage sludge residue under anaerobic conditions for mine tailings remediation

Previous studies showed that 85 % of total organic matter (TOM) in digested sewage sludge (biosolids) used as a sealing layer material over sulfide tailings at the Kristineberg Mine, northern Sweden, had been degraded 8 years after application, resulting in a TOM reduction from 78 to 14 %. To achieve a better understanding of the field observations, laboratory studies were performed to evaluate biodegradation rates of the TOM under anaerobic conditions. Results reveal that the original biosolid consisted of ca. 60 % TOM (48.0 % lignin and 11.8 % carbohydrates) that had not been fully degraded. The incubation experiments proved that 27.8 % TOM in the biosolid was further degraded anaerobically at 20–22 °C during the 230 days’ incubation period, and that a plateau to the biodegradation rate was approached. Based on model results, the degradation constant was found to be 0.0125 (day^?1). The calculated theoretical gas formation potential was ca. 50 % higher than the modeled results based on the average degradation rate. Cumulated H₂S equated to 0.65 μmoL g^?1 of biosolid at 230 days. However, the large sulfurous compounds reservoir (1.76 g SO₄ ^2? kg^?1 biosolid) together with anaerobic conditions can generate high concentrations of this gas over a long-term perspective. Due to the rate of biodegradability identified via anaerobic processes, the function of the biosolid to serve as an effective barrier to inhibit oxygen migration to underlying tailings, may decrease over time. However, a lack of readily degradable organic fractions in the biosolid and a large fraction of organic matter that was recalcitrant to degradation suggest a longer degradation duration, which would prolong the biosolid material’s function and integrity.     

Plan‐form evolution of ancient meandering rivers reconstructed from longitudinal outcrop sections

The mode of channel‐bend transformation (i.e. expansion, translation, rotation or a combination thereof) has a direct bearing on the dimensions, shape, bedding architecture and connectivity of point‐bar sandstone bodies within a fluvial meander belt, but is generally difficult to recognize in vertical outcrops. This study demonstrates how the bend transformation mode and relative rate of channel‐floor aggradation can be deciphered from longitudinal outcrop sections aligned parallel to the meander‐belt axis, as a crucial methodological aid to the reconstruction of ancient fluvial systems and the development of outcrop analogue models for fluvial petroleum reservoirs. The study focuses on single‐storey and multi‐storey fluvial meander‐belt sandstone bodies in the Palaeogene piggyback Boyabat Basin of north‐central Turkey. The sandstone bodies are several hundred metres wide, 5 to 40 m thick and encased in muddy floodplain deposits. The individual channel‐belt storeys are 5 to 9 m thick and their transverse sections show lateral‐accretion bed packages representing point bars. Point bars in longitudinal sections are recognizable as broad mounds whose parts with downstream‐inclined, subhorizontal and upstream‐inclined bedding represent, respectively, the bar downstream, central and upstream parts. The inter‐bar channel thalweg is recognizable as the transition zone between adjacent point‐bar bedsets with opposing dip directions into or out of the outcrop section. The diverging or converging adjacent thalweg trajectories, or a trajectory migrating in up‐valley direction, indicate point‐bar broadening and hence channel‐bend expansion. A concurrent down‐valley migration of adjacent trajectories indicates channel‐bend translation. Bend rotation is recognizable from the replacement of a depositional riffle by an erosional pool zone or vice versa along the thalweg trajectory. The steepness of the thalweg trajectory reflects the relative rate of channel‐floor aggradation. This study discusses further how the late‐stage foreland tectonics, with its alternating pulses of uplift and subsidence and a progressive narrowing of the basin, has forced aggradation of fluvial channels and caused vertical stacking of meander belts.     

The Inference of Geo-Mechanical Properties of Soft Rocks and their Degradation from Needle Penetration Tests

Needle penetration tests (NPTs) are used for inferring the uniaxial compressive strength of soft rocks, particularly in tunneling through squeezing rocks and foundations on weathered rocks in Japan. The device measures the applied load and the penetration depth of its needle. The ratio of applied load to penetration depth was originally called the needle penetration index (NPI). In this study, this device has been used to infer the geo-mechanical properties of soft rocks from Japan, Turkey, Indonesia, and Egypt. Various equations are presented to infer the geo-mechanical properties in terms of the NPI and compared with the experimental results. The possibility of evaluating the anisotropy of geo-mechanical properties is shown. Furthermore, the characterization of geo-mechanical properties of fault/fracture and slip (shear) surfaces is explained. Some additional equations are given to consider the degradation of geo-mechanical properties as a function of water content, weathering state, and number of cycles of freezing–thawing. Furthermore, the possibility of evaluating the time-dependency characteristics of soft rocks by needle penetration testing is discussed through experiments. It is shown that the effects of water content, weathering state, and number of cycles of freezing–thawing and time-dependency can be evaluated using the NPT technique.     

New lessons for technology policy and climate change: investment for innovation

The direction of UK energy policy requires a renewed impetus if the goal of climate change stabilization is to be met. Cost is not the main issue: a transformation to a low-carbon energy system may be no more expensive than meeting future energy demands with fossil fuels. Institutional barriers are preventing the large-scale adoption of the necessary technologies. New institutions to promote low-carbon technologies have not yet led to investment on the necessary scale. Further changes to the operation of the UK electricity markets to create a ‘level playing field’ for small-scale and intermittent generation are necessary. UK policy can contribute to international agreements following on from the Kyoto Accord, which also need to address the institutional barriers to energy technology development and transfer.