Obliquity-driven mountain permafrost-related fluvial magnetic susceptibility cycles in the Quaternary mid-latitude long-term (2.5 Ma) fluvial Maros Fan in the Pannonian Basin

Magnetic susceptibility (MS) of the Quaternary long-term mid-latitude Maros fluvial fan (Pannonian Basin) was recorded to understand the stratigraphical features of source-proximal fluvial depositional settings. Three fully cored 500-m-deep boreholes were sampled at 0.5-m intervals; low-field and frequency dependent MS were measured, and complementary hysteresis and SEM-EDAX investigations were performed on selected samples. Logged susceptibility data were also used to log correlations established by a simultaneous comparison of wireline log and laboratory measurements. Time-series analyses of the susceptibility records reveal a ~41-ka and ~100-ka cyclicity. Towards the source-distal sections the intensity of the ~41-ka cycles decreases, while that of the ~100-ka cycles remains strong. Stratigraphical and spectral similarities were observed between the Maros fluvial fan and Chinese loess records; however, based on complementary magnetic data, the magnetic phase of the Maros Fan sections is related to the detrital magnetite that originates from the catchment during early postglacial permafrost degradations. The amplification of the ~41-ka cycles can be attributed to the very high susceptibility values in source-proximal settings and to the special stratigraphical feature of the distributive fluvial systems. This comprises the increased avulsion frequency on the fluvial fans in ‘glacial recession periods’, in concert with the ‘early postglacial’ occurrence of the permafrost-related magnetite originating from the catchment. As a local phenomenon, this is significant since it records the obliquity-driven variations in permafrost development in a catchment. However, fluvial and alluvial fans are widespread depositional landforms within the Eurasian mountain range and were possibly the same during the Quaternary deglaciations. Thus, obliquity-driven magnetic susceptibility variations in source-proximal fan deposits attached or adjacent to regions of loess deposition should also be considered when scanning for potential source material of aeolian deposits.     

http://www.sciencedirect.com/science/article/pii/S1674987111000776

The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists mainly of a subhorizontal gold-quartz vein perpendicular to subvertical shear zones. The 0.3e0.5 m thick vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening and mineral precipitation. Measurement of the c-axis of primary growth quartz indicates that quartz preferentially grew perpendicular to the fracture, suggesting open space filling and/or extensional nature of the fracture. Measurement of the orientations of microfractures, veinlets and fluideinclusion planes (FIPs) crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum principal stress (s1), which is inconsistent with the subhorizontal s1 inferred from the regional stress field with NeS shortening. This apparent discrepancy is explained by invoking episodic fluid pressure fluctuation between supralithostatic and hydrostatic regimes accompanied by episodic opening and closing of the subhorizontal fracture. When fluid pressure was higher than the lithostatic value, the fracture was opened and primary growth minerals were precipitated, whereas when fluid pressure decreased toward the hydrostatic value, the hanging wall of the fracture collapsed, causing collision of protruding primary growth minerals from both sides of the fracture and resulting in formation of vein-parallel deformation bands. The columns where the two facing sides of the fracture collided were subject to higher-than-lithostatic stress due to the bridging effect and reduced support surface area, explaining the development of vertical s1. This hypothesis is consistent the fault-valve model, and explains the flipping of s1 without having to change the regional stress field.     

Possible Effect of the Earth’s Inertial Induction on the Orbital Decay of LAGEOS

The theory of velocity dependent inertial induction, based upon extended Mach’s principle, has been able to generate many interesting results related to celestial mechanics and cosmological problems. Because of the extremely minute magnitude of the effect its presence can be detected through the motion of accurately observed bodies like Earth satellites. LAGEOS I and II are medium altitude satellites with nearly circular orbits. The motions of these satellites are accurately recorded and the past data of a few decades help to test many theories including the general theory of relativity. Therefore, it is hoped that the effect of the Earth’s inertial induction can have any detectable effect on the motion of these satellites. It is established that the semi-major axis of LAGEOS I is decreasing at the rate of 1.3 mm/d. As the atmospheric drag is negligible at that altitude, a proper explanation of the secular change has been wanting, and, therefore, this paper examines the effect of the Earth’s inertial induction effect on LAGEOS I. Past researches have established that Yarkovsky thermal drag, charged and neutral particle drag might be the possible mechanisms for this orbital decay. Inertial induction is found to generate a perturbing force that results in 0.33 mm/d decay of the semi major axis. Some other changes are also predicted and the phenomenon also helps to explain the observed changes in the orbits of a few other satellites. The results indicate the feasibility of the theory of inertial induction i.e. the dynamic gravitation phenomenon of the Earth on its satellites as a possible partial cause for orbital decay.     

Effect of Random Inclusion of Polypropylene Fibers on Strength Characteristics of Cohesive Soil

This paper presents the effect of random inclusion of polypropylene fibers on strength characteristics of soil. Locally available cohesive soil (CL) is used as medium and polypropylene fibers with three aspect ratios (l/d = 75, 100 and 125) are used as reinforcement. Soil is compacted with standard Proctor’s maximum density with low percentage of reinforcement (0–1% by weight of oven-dried soil). Direct shear tests, unconfined compression tests and CBR tests were conducted on un-reinforced as well as reinforced soil to investigate the strength characteristics of fiber-reinforced soil. The test results reveal that the inclusion of randomly distributed polypropylene fibers in soil increases peak and residual shear strength, unconfined compressive strength and CBR value of soil. It is noticed that the optimum fiber content for achieving maximum strength is 0.4–0.8% of the weight of oven-dried soil for fiber aspect ratio of 100.     

Understanding of the biochemical events in a chemo-bioreactor during continuous acid mine drainage treatment

Spent mushroom compost (SMC) is widely used as reactor matrix in passive bioreactor involving sulfate reducing bacteria (SRB) for acid mine drainage (AMD) treatment. Follow-up our previous report, recent work has been established the extent of activity, sustained organic carbon availability, and the biochemical events of successive alkalinity producing system-based chemo-bioreactor for continuous performance using SMC. Removal of iron and sulfate from influent was over 77 and 90%, respectively, for first 13 weeks, while sulfate removal efficiency suddenly dropped down to 31% thereafter. Ahead of 13th week, process failure was beginning to be noticed when available dissolved organic carbon (DOC) value dropped down to 50 mg/L. SRB population was mostly affected with DOC drought at this stage. Sulfur was one of the major elements found with other tested metals in blackish green effluent precipitate. Sulfide compounds of the tested metals were formed on both exhausted chemo-bioreactor bed and precipitate. FTIR analysis indicated that SMC was responsible for metal binding and available nutrients supply. The present study revealed the feasibility of SMC as a host for treating AMD by this chemo-bioreactor that will assist in designing the continuous treatment practice.     

Variogram Fractal Dimension Based Features for Hyperspectral Data Dimensionality Reduction

In this paper a new approach for fractal based dimensionality reduction of hyperspectral data has been proposed. The features have been generated by multiplying variogram fractal dimension value with spectral energy. Fractal dimension bears the information related to the shape or characteristic of the spectral response curves and the spectral energy bears the information related to class separation. It has been observed that, the features provide accuracy better than 90 % in distinguishing different land cover classes in an urban area, different vegetation types belonging to an agricultural area as well as various types of minerals belonging to the same parent class. Statistical comparison with some conventional dimensionality reduction methods validates the fact that the proposed method, having less computational burden than the conventional methods, is able to produce classification statistically equivalent to those of the conventional methods.     

Palynological evidence for the Palaeocene evolution of the forearc basin, Indus Suture Zone, Ladakh, India

The discovery of Permian, Mesozoic and Palaeocene palynomorphs from the Nindam forearc basin, exposed along the Indus Suture Zone in Ladakh, is reported. The palynomorphs are from volcanogenic sandstones and are poorly preserved, distorted and show the effects of abrasion (striation marks). The frequent occurrence of Proxapertites indicates the assemblage is at least Palaeocene in age. The Palaeocene palynomorphs and sediments were transported to the Nindam trough from nearby elevated landward regions (islands). These Palaeocene provenance areas were characterized by an estuarine, nearshore, tropical, warm‐humid environment and were situated at equatorial palaeolatitudes. However, the occurrence of Permian and Mesozoic palynomorphs in the assemblage indicates that the Late Palaeozoic and Mesozoic Tethyan sedimentary rocks exposed along the northern margin of the Indian plate were redeposited into the tectonically active Cretaceous–Palaeocene trench–subduction complex that existed between the Indian and the Asian plates until the collision took place at ～50–60 Ma.     

Fractal compression of satellite images

Fractal geometry provides a means for describing and analysing the complexity of various features present in digital images. In this paper, characteristics of Fractal based compression of satellite data have been tested for Indian Remote Sensing (IRS) images (of different bands and resolution). The fidelity and efficiency of the algorithm and its relationship with spatial complexity of images is also evaluated. Results obtained from fractal compression have been compared with popularly used compression methods such as JPEG 2000, WinRar. The effect of bands and pixel resolution on the compression rate has also been examined. The results from this study show that the fractal based compression method provides higher compression rate while maintaining the information content of RS images to a great extent than that of JPEG. This paper also asserts that information loss due to fractal compression is minimal. It may be concluded that fractal technique has many potential advantages for compression of satellite images.