Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

We report on the coronal hole (CH) influence on the 54 magnetic cloud (MC) and non-MC associated coronal mass ejections (CMEs) selected for studies during the Coordinated Data Analysis Workshops (CDAWs) focusing on the question if all CMEs are flux ropes. All selected CMEs originated from source regions located between longitudes 15E?–?15W. Xie, Gopalswamy, and St. Cyr (2013, Solar Phys., doi: 10.1007/s11207-012-0209-0 ) found that these MC and non-MC associated CMEs are on average deflected towards and away from the Sun–Earth line, respectively. We used a CH influence parameter (CHIP) that depends on the CH area, average magnetic field strength, and distance from the CME source region to describe the influence of all on-disk CHs on the erupting CME. We found that for CHIP values larger than 2.6 G the MC and non-MC events separate into two distinct groups where MCs (non-MCs) are deflected towards (away) from the disk center. Division into two groups was also observed when the distance to the nearest CH was less than 3.2×10⁵ km. At CHIP values less than 2.6 G or at distances of the nearest CH larger than 3.2×10⁵ km the deflection distributions of the MC and non-MCs started to overlap, indicating diminishing CH influence. These results give support to the idea that all CMEs are flux ropes, but those observed to be non-MCs at 1 AU could be deflected away from the Sun–Earth line by nearby CHs, making their flux rope structure unobservable at 1 AU.     

Calibration of paired watersheds: Utility of moving sums in presence of externalities

Historically, paired watershed studies have been used to quantify the hydrological effects of land use and management practices by concurrently monitoring 2 similar watersheds during calibration (pretreatment) and post‐treatment periods. This study characterizes seasonal water table and flow response to rainfall during the calibration period and tests a change detection technique of moving sums of recursive residuals (MOSUM) to select calibration periods for each control–treatment watershed pair when the regression coefficients for daily water table elevation were most stable to minimize regression model uncertainty. The control and treatment watersheds were 1 watershed of 3–4‐year‐old intensely managed loblolly pine (Pinus taeda L.) with natural understory, 1 watershed of 3–4‐year‐old loblolly pine intercropped with switchgrass (Panicum virgatum), 1 watershed of 14–15‐year‐old thinned loblolly pine with natural understory (control), and 1 watershed of switchgrass only. The study period spanned from 2009 to 2012. Silvicultural operational practices during this period acted as external factors, potentially shifting hydrologic calibration relationships between control and treatment watersheds. MOSUM results indicated significant changes in regression parameters due to silvicultural operations and were used to identify stable relationships for water table elevation. None of the calibration relationships developed using this method were significantly different from the classical calibration relationship based on published historical data. We attribute that to the similarity of historical and 2010–2012 leaf area index on control and treatment watersheds as moderated by the emergent vegetation. Although the MOSUM approach does not eliminate the need for true calibration data or replace the classic paired watershed approach, our results show that it may be an effective alternative approach when true data are unavailable, as it minimizes the impacts of external disturbances other than the treatment of interest.     

Flow dynamics at the origin of thin clayey sand lacustrine turbidites: Examples from Lake Hazar,Turkey

Turbidity currents and their deposits can be investigated using several methods, i.e. direct monitoring, physical and numerical modelling, sediment cores and outcrops. The present study focused on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in eleven clusters of closely spaced thin beds. Depositional processes and sources for three of those eleven clusters are studied at three coring sites. Bathymetrical data and seismic reflection profiles are used to understand the specific geomorphology of each site. X‐ray, thin sections and CT scan imagery combined with grain‐size, geochemical and mineralogical measurements on the cores allow characterization of the turbidites. Turbidites included in each cluster were produced by remobilization of surficial slope sediment, a process identified in very few studies worldwide. Three types of turbidites are distinguished and compared with deposits obtained in flume studies published in the literature. Type 1 is made of an ungraded clayey silt layer issued from a cohesive flow. Type 2 is composed of a partially graded clayey sand layer overlain by a mud cap, attributed to a transitional flow. Type 3 corresponds to a graded clayey sand layer overlain by a mud cap issued from a turbulence‐dominated flow. While the published experimental studies show that turbulence is damped by cohesion for low clay content, type 3 deposits of this study show evidence for a turbulence‐dominated mechanism despite their high clay content. This divergence may in part relate to input variables, such as water chemistry and clay mineralogy, that are not routinely considered in experimental studies. Furthermore, the large sedimentological variety observed in the turbidites from one coring site to another is related to the evolution of a sediment flow within a field‐scale basin made of a complex physiography that cannot be tackled by flume experiments.     

Biostratigraphy and seismic data analysis to detect the sequence stratigraphic depositional environment of the Miocene succession: Gulf of Suez (Egypt)

This work comprises a study of the sequence stratigraphy, seismic-facies analysis, biostratigraphy and depositional environments of the northern part of the Gulf of Suez, Egypt, using a set of 24 3D seismic profiles, composite logs and sonic logs from ten wells. The syn-rift formations in the studied ten wells are described lithologically and interpreted based on investigating two seismic profiles. Biostratigraphically, the Miocene fossils are identified to correlate the five planktonic foraminiferal biozones in the examined boreholes (RB-A1, RB-B1, RB-B3, EE85-2 and RB-C1). The sequence stratigraphic analysis suggests that the Miocene succession can be subdivided into two major third order depositional sequences (S1 and S2) separated by the three major sequence boundaries (DSB1, DSB2 and DSB3).     

Composition,radioactivity, and possible applications of kaolin deposits of Sinai,Egypt

This work discusses the composition, radioactivity, and possible utilization of the kaolin resources in Sinai which are hosted in thick sandstone sequences belonging to the Carboniferous (Wadi Khaboba) and Early Cretaceous (Wadi Iseila and Abansakar) ages. The characterization of kaolin was done by microscopic and SEM examination, supported by XRD and ICP-MS analyses. The studied kaolin resources consist of kaolinite, as the main constituent, associated with subsidiary dickite and halloysite, and minor contribution of smectite and illite. The most dominant non-clay mineral is quartz, besides minor gypsum, dolomite, and hematite. Ferrugination dominates, in most cases, at the upper boundaries of the kaolin lenses, suggesting possible supergene activity. The high Al₂O₃/SiO₂ ratio for the Cretaceous kaolin (0.54, in average) specifies its better grade relative to the Carboniferous kaolin (0.43, in average). The kaolin of the middle part of lens C in Wadi Iseila contains Si/Al molecular ratio of about unity, suggesting high-grade kaolin. The Carboniferous kaolin has enriched the radionuclides: U, Th, and Ra (at disequilibrium state due to leaching of eU relative to Ra) and the REE, relative to that of the Cretaceous age. The Carboniferous kaolin is characterized by a higher contribution of HREE (zircon signature), whereas LREE seems to be more influential for the Early Cretaceous kaolin (monazite signature). In spite of the very high CIA index (93 to 99), none of the analyzed kaolin deposits displays Ce abnormality. The high radioactivity of some Carboniferous kaolin can be a serious impediment for its utilization or its exportation. The kaolin of Sinai does not satisfy the international standards for paperwork industries and refractory manufacturing, but beneficiation may overcome this challenge. However, some lenses have high-grade kaolin with a low percentage of oxides of iron, magnesium, calcium, sodium, and potassium and a low radioactivity, hence nominated for the local refractory industry. The high-grade kaolin of Sinai fulfills the standards required for ceramics manufacturing in the global market. Grade 3 kaolin (< 30%, Al₂O₃) can be used in the manufacturing of white Portland cement and red glaze manufacturing on both local and global markets.     

Origin of dyke swarms in Wadi El Redi-Wadi Lahami area,southern Eastern Desert of Egypt

Dykes predominate within the Neoproterozoic rocks, especially granites, of Wadi El Redi-Wadi Lahami area in the southern Eastern Desert of Egypt. The dyke swarms form three major suites: from the oldest to the youngest, they are basaltic andesite—Suite 1 (E-W and ENE-WSW), rhyolite—Suite 2 (NE-SW), and andesite—Suite 3 (NNE-SSW, NNW-SSE, and NW-SE). Despite the wide ranges of the dyke compositions, the feldspar and amphibole are usually the essential forming minerals. The plagioclase arrays between Ab_0.9An_99.10 in the basaltic andesite and Ab_98.80An_0.70 in the rhyolite, while sanidine ranges from Or_44.60Ab_49.70 to Or_98.40Ab_1.60. Amphibole in Suite 1 and 3 (Al₂O₃, TiO₂, Na₂O, and K₂O are the lowest and those of SiO₂ and CaO are the highest) samples are usually magnesio-hornblende, whereas it is edenite and tschermakite in Suite 2 dykes. Despite all parent magmas have calc-alkaline affinity, some elements such as Ni show an erratic behavior against the progressing differentiation from one magma chamber and implying for an assimilation of the country rocks. The high contents of amphibole, the depletion in Ti, and the enrichment in large-ion lithophile elements (such as K, Rb, Ba, Sr, and Ba) compared to the primitive mantle composition are consistent with parent hydrous melts generated due to extension above the subduction zone. The estimated compositions of liquids in equilibrium with amphiboles and the pressures at which they crystallized (4.61–7.8 kbar for the Suite 2 and 1.5–2 kbar for the Suites 1 and 3) are greatly varied. These are indications for a difference in the source regions of the parent magmas of the studied dykes. It is supposed that the Suite 1 and 2 dykes are a conjugate set emplaced due to the NW-SE crustal extension in the Arabian-Nubian shield, whereas the Suite 3 dykes generated due to the rifting along the Red Sea.     

The effectiveness of the very low frequency electromagnetic method (VLF-EM) in the exploration of sulphide mineralization in arid environments,case study from South Sinai Peninsula,Egypt

Very low frequency electromagnetic (VLF-EM) measurements were carried out in Wadi Isbayia area, south Sinai Peninsula, to test the efficiency of the VLF-EM method in the exploration of sulphide mineralization in arid environments. The VLF-EM field measurements, including tilt angle, real and imaginary components of the received VLF field, were carried out along fifteen profiles covering a quartz monzonite bedrock. Interpretation of the VLF measurements, in the light of geological information, has showed that sulphide minerals in the Wadi Isbayia area extend from the ground surface to a depth of about 200 m. However, the structural lineaments, especially faults, have controlled the distribution of the sulphide mineralization. A few of polished sections for rock samples, collected from the sites of the VLF-EM anomalies in the study area, have been prepared and examined by ore microscopy which confirmed the presence of pyrite and chalcopyrite as well as iron oxides, disseminated in the quartz monzonite bedrock. These results showed that the VLF-EM method is an effective tool in the exploration of sulphide minerals in the arid environments.