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71.
Qahtan A. M. Al Nuaimy 《Arabian Journal of Geosciences》2017,10(24):542
A biometric study of Chattian–Early Aquitanian taxa from shallow marine transgressive carbonate deposits in the Oligo-Miocene sedimentary basin of Kirkuk, Iraq, provides new insight into their taxonomy, stratigraphy, and palaeobiogeography. Their evolution is based on a distinct change in general nepiont morphology, which agrees with the principle of nepionic acceleration. Each Miogypsinoides group is represented by more than one lineage. We demonstrate for the first time the parallel evolution of Miogypsina and Miogypsinoides in the late Chattian of north-eastern Iraq. We assign specimens into two lineage groups: Miogypsinoides formosensis of the Late Chattian, with smaller embryon and longer post-embryonic spirals, which evolved into Miogypsinoides bantamensis of the Early Aquitanian; and Miogypsinoides sivasensis, with shorter spirals and larger embryon, originally found in late Chattian to Early Aquitanian deposits. This group evolved into large embryon and longer post-embryonic spiral specimens of the upper Azkand Formation, assigned to Miogypsinoides dehaartii and associated with Miogypsina gunteri-basraensis and M. gunteri due to their peculiar morphological features. Miogypsina specimens are related to Miogypsina basraensis, which have much smaller embryon dimensions. This part of the sequence corresponds to Ms. formosensis and is overlain by a Miogypsina ex. interc. gunteri-basraensis succession, a composite species that evolved to Miogypsina gunteri, the most common Miogypsinids taxon in the carbonate upper Azkand Formation, thereby acting as a reference for the evolution of this taxon and its transition to M. ex. interc. tani-gunteri. Miogypsinoides evolution in the Iraqi sedimentary basin is similar to Western Tethys evolution yet differs from Indo-Pacific evolution. 相似文献
72.
Gravimetric monitoring of the first field‐wide steam injection in a fractured carbonate field in Oman – a feasibility study 下载免费PDF全文
Marcin Glegola Pavel Ditmar Femke Vossepoel Rob Arts Fahad Al‐Kindy Roland Klees 《Geophysical Prospecting》2015,63(5):1256-1271
Gas‐Oil Gravity Drainage is to be enhanced by steam injection in a highly fractured, low permeability carbonate field in Oman. Following a successful pilot, field‐wide steam injection is being implemented, first of this type in the world. A dedicated monitoring program has been designed to track changes in the reservoir. Various observations are to be acquired, including, surface deformation, temperature measurements, microseismic, well logs, pressure and saturation measurements to monitor the reservoir. Because significant changes in the reservoir density are expected, time‐lapse gravimetry is also being considered. In this paper we investigate the feasibility of gravimetric monitoring of the thermally enhanced gravity drainage process at the carbonate field in Oman. For this purpose, forward gravity modelling is performed. Based on field groundwater measurements, the estimates of the hydrological signal are considered and it is investigated under what conditions the groundwater influences can be minimized. Using regularized inversion of synthetic gravity data, we analyse the achievable accuracy of heat‐front position estimates. In case of large groundwater variations at the field, the gravity observations can be significantly affected and, consequently, the accuracy of heat‐front monitoring can be deteriorated. We show that, by applying gravity corrections based on local observations of groundwater, the hydrological influences can to a large extent be reduced and the accuracy of estimates can be improved. We conclude that gravimetric monitoring of the heat‐front evolution has a great potential. 相似文献
73.
Ecohydrographic constraints on biodiversity and distribution of phytoplankton and zooplankton in coral reefs of the Red Sea,Saudi Arabia 下载免费PDF全文
Benjamin Kürten Hisham S. Khomayis Reny Devassy Saskia Audritz Ulrich Sommer Ulrich Struck Mohsen M. El‐Sherbiny Ali M. Al‐Aidaroos 《Marine Ecology》2015,36(4):1195-1214
An integral concept of ecological research is the constraint of biodiversity along latitudinal and environmental gradients. The Red Sea features a natural example of a latitudinal gradient of salinity, temperature and nutrient richness. Coral reefs along the Red Sea coasts are supported with allochthonous resources such as oceanic and neritic phytoplankton and zooplankton; however, relatively little is known about how the ecohydrography correlates with plankton biodiversity and abundance. In this article we present the biodiversity of phytoplankton and zooplankton in Red Sea coral reefs. Oceanographic data (temperature, salinity), water samples for nutrient analysis, particulate organic matter, phytoplankton and zooplankton, the latter with special reference to Copepoda (Crustacea), were collected at nine coral reefs over ~1500 km distance along the Red Sea coast of Saudi Arabia. The trophic state of ambient waters [as indicated by chlorophyll a (Chl a)] changed from strong oligotrophy in the north to mesotrophy in the south and was associated with increasing biomasses of Bacillariophyceae, picoeukaryotes and Synechococcus as indicated by pigment fingerprinting (CHEMTAX) and flow cytometry. Net‐phytoplankton microscopy revealed a Trichodesmium erythraeum (Cyanobacteria) bloom north of the Farasan Islands. Several potentially harmful algae, including Dinophysis miles and Gonyaulax spinifera (Dinophyceae), were encountered in larger numbers in the vicinity of the aquaculture facilities at Al Lith. Changes in zooplankton abundance were mainly correlated to the phytoplankton biomass following the latitudinal gradient. The largest zooplankton abundance was observed at the Farasan Archipelago, despite high abundances of copepodites, veligers (Gastropoda larvae) and Chaetognatha at Al Lith. Although the community composition changed over latitude, biodiversity indices of phytoplankton and zooplankton did not exhibit a systematic pattern. As this study constitutes the first current account of the plankton biodiversity in Red Sea coral reefs at a large spatial scale, the results will be informative for ecosystem‐based management along the coastline of Saudi Arabia. 相似文献
74.
Lineament extraction and analysis is one of the routine work in mapping medium and large areas using remote sensing data, most of which are satellite images. Landsat Enhanced Thematic Mapper (ETM) of 945×1 232 pixels subscene acquired on 21 March 2000 covering the northwestern part of Yunnan Province has been digitally processed using ER Mapper software. This article aims to produce lineament density map that predicts favorable zones for hydrothermal mineral occurrences and quantify spatial associations between the known hydrothermal mineral deposits. In the process of lineament extraction a number of image processing techniques were applied. The extracted lineaments were imported into MapGIS software and a suitable grid of 100 m×100 m was chosen. The Kriging method was used to create the lineament density map of the area. The results show that remote sensing data could be useful to extract the lineaments in the area. These lineaments are closely correlated with the faults obtained through other geological investigation methods. On comparing with field data the lineament-density map identifies two important high prospective zones, where large-scale deposits are already existing. In addition the map highlights unrecognized target areas that require follow up investigation. 相似文献
75.
Environmental isotopic and hydrochemical study of water in the karst aquifer and submarine springs of the Syrian coast 总被引:1,自引:0,他引:1
The groundwater of major karst systems and submarine springs in the coastal limestone aquifer of Syria has been investigated using chemical and isotopic techniques. The δ18O values of groundwater range from ?6.8 to ?5.05‰, while those for submarine springs vary from ?6.34 to +1.08‰ (eastern Mediterranean seawater samples have a mean of +1.7‰). Groundwater originates from the direct infiltration of atmospheric water. Stable isotopes show that the elevation of the recharge zones feeding the Banyas area (400–600 m a.s.l.) is higher than that feeding the Amrit area (100–300 m a.s.l.). The 18Oextracted (18O content of the seawater contribution) for the major submarine springs suggests a mean recharge area elevation of 600–700 m a.s.l., and lower than 400 m a.s.l. for the spring close to Amrit. Based on the measured velocity and the percentage of fresh water at the submarine springs outlet, the estimated discharge rate is 350 million m3/year. The tritium concentrations in groundwater (1.6–5.9 TU) are low and very close to the current rainfall values (2.9–5.6 TU). Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m3 was obtained for the maximum groundwater reservoir size. 相似文献
76.
Y. B. Onundi M.Sc. A. A. Mamun Ph.D. M. F. Al Khatib Ph.D. Y. M. Ahmed M.Sc. 《International Journal of Environmental Science and Technology》2010,7(4):751-758
Granular activated carbon produced from palm kernel shell was used as adsorbent to remove copper, nickel and lead ions from a synthesized industrial wastewater.Laboratory experimental investigation was carried out to identify the effect of pH and contact time on adsorption of lead, copper and nickel from the mixed metals solution. Equilibrium adsorption experiments at ambient room temperature were carried out and fitted to Langmuir and Freundlich models. Results showed that pH 5 was the most suitable, while the maximum adsorbent capacity was at a dosage of 1 g/L, recording a sorption capacity of 1.337 mg/g for lead, 1.581 mg/g for copper and 0.130 mg/g for nickel. The percentage metal removal approached equilibrium within 30 min for lead, 75 min for copper and nickel, with lead recording 100 %, copper 97 % and nickel 55 % removal, having a trend of Pb2+ > Cu2+ > Ni2+. Langmuir model had higher R2 values of 0.977, 0.817 and 0.978 for copper, nickel and lead respectively, which fitted the equilibrium adsorption process more than Freundlich model for the three metals. 相似文献
77.
78.
The Ras Al-Subiyah area is considered one of the most promising areas in Kuwait for future development. This development will
include a new town called Subiyah and its associated infrastructure. This area is also being considered as the location for
connection between Boubyan Island, which is now undergoing major development and the Kuwait mainland. The present study investigates
the geomorphology of the Ras Al-Sabiyah area in the northern sector of Kuwait. The study area is generally flat, and it is
located west of the Jal Az-Zor escarpment. It is bordered on the east by the Khor Al-Sabiyah tidal channel and on the south
by Kuwait Bay. The area receives sediments from several sources; currently the most important are aeolian sediments and the
deposition of mud delivered through the Khor Al-Sabiyah from the Iraqi marshes. The study area has been subjected to severe
environmental changes due to the Gulf wars and the drainage of Iraqi marshes and the associated artificial changes in fluvial
system. Twenty-two surface sediments were collected from the Ras Al-Subiyah area. Samples were collected to include the main
geomorphologic characteristic features of the study area. Field observations and remote sensing images from 1990 and 2001
were used to produce an updated geomorphologic map for the Ras Al-Subiyah and a map showing geomorphic changes between 1990
and 2001. Grain size of the surface sediment ranges from gravel to medium sand. In general, grain size statistical analysis
indicates that most of the areas are composed of two or more classes of sands transported and deposited from different sources
including aeolian, sabkhas, river and the bays. The variability in the grain size statistical parameters may be attributed
to the complexity of surface morphology as well as the diversity in the type of depositional environment in the Ras Al-Subiyah
area. The total area subjected to change during the 12-year period (1990–2001) is about 32 km2 as calculated using GIS techniques. 相似文献
79.
Petrology and geochemistry of feldspathic impact‐melt breccia Abar al' Uj 012, the first lunar meteorite from Saudi Arabia 下载免费PDF全文
Marianna Mészáros Beda A. Hofmann Pierre Lanari Randy L. Korotev Edwin Gnos Nicolas D. Greber Ingo Leya Richard C. Greenwood A. J. Timothy Jull Khalid Al‐Wagdani Ayman Mahjoub Abdulaziz A. Al‐Solami Siddiq N. Habibullah 《Meteoritics & planetary science》2016,51(10):1830-1848
Abar al' Uj (AaU) 012 is a clast‐rich, vesicular impact‐melt (IM) breccia, composed of lithic and mineral clasts set in a very fine‐grained and well‐crystallized matrix. It is a typical feldspathic lunar meteorite, most likely originating from the lunar farside. Bulk composition (31.0 wt% Al2O3, 3.85 wt% FeO) is close to the mean of feldspathic lunar meteorites and Apollo FAN‐suite rocks. The low concentration of incompatible trace elements (0.39 ppm Th, 0.13 ppm U) reflects the absence of a significant KREEP component. Plagioclase is highly anorthitic with a mean of An96.9Ab3.0Or0.1. Bulk rock Mg# is 63 and molar FeO/MnO is 76. The terrestrial age of the meteorite is 33.4 ± 5.2 kyr. AaU 012 contains a ~1.4 × 1.5 mm2 exotic clast different from the lithic clast population which is dominated by clasts of anorthosite breccias. Bulk composition and presence of relatively large vesicles indicate that the clast was most probably formed by an impact into a precursor having nonmare igneous origin most likely related to the rare alkali‐suite rocks. The IM clast is mainly composed of clinopyroxenes, contains a significant amount of cristobalite (9.0 vol%), and has a microcrystalline mesostasis. Although the clast shows similarities in texture and modal mineral abundances with some Apollo pigeonite basalts, it has lower FeO and higher SiO2 than any mare basalt. It also has higher FeO and lower Al2O3 than rocks from the FAN‐ or Mg‐suite. Its lower Mg# (59) compared to Mg‐suite rocks also excludes a relationship with these types of lunar material. 相似文献
80.
Alina Ristea Mohammad Al Boni Bernd Resch Matthew S. Gerber Michael Leitner 《International journal of geographical information science》2020,34(9):1708-1739
ABSTRACT Sporting events attract high volumes of people, which in turn leads to increased use of social media. In addition, research shows that sporting events may trigger violent behavior that can lead to crime. This study analyses the spatial relationships between crime occurrences, demographic, socio-economic and environmental variables, together with geo-located Twitter messages and their ‘violent’ subsets. The analysis compares basketball and hockey game days and non-game days. Moreover, this research aims to analyze crime prediction models using historical crime data as a basis and then introducing tweets and additional variables in their role as covariates of crime. First, this study investigates the spatial distribution of and correlation between crime and tweets during the same temporal periods. Feature selection models are applied in order to identify the best explanatory variables. Then, we apply localized kernel density estimation model for crime prediction during basketball and hockey games, and on non-game days. Findings from this study show that Twitter data, and a subset of violent tweets, are useful in building prediction models for the seven investigated crime types for home and away sporting events, and non-game days, with different levels of improvement. 相似文献