Morphological characteristics and development of coastal nabkhas, north-east Kuwait

The coastal aeolian nabkhas, in Kuwait, are mostly elongated, with an average length of about 10 m, an average width of 3.7 m, and an average height of 0.65 m. The horizontal component of the nabkha dune (HC: the mean of the length and width of nabkha dune), developed around Nitraria retusa, was measured and compared with the height of the shrub. A second-polynomial function was found to best fit the set of data. The fitting identified three trends of the development of the nabkhas. Initially, as the height of shrubs (H) increases, the HC increases linearly until it reaches approximately 10 m. When H exceeds 2 m, the effect of shrub height becomes ineffective in trapping more sediments; that is, reaching an equilibrium condition, before a decrease in shrub height effectiveness occurs. Sediments of the nabkha crest and wings, left and right sides, are subjected to high energy winds, and therefore, they are generally coarser and better sorted than those of the tail or the nose. Minor differences are noted in the textural characteristics and the mineral composition of nabkha sediments and those of other aeolian landforms found in upwind nabkha field; this indicates that the sediments were derived from the nearby sources.     

Age and tectonomagmatic setting of the Eocene Çöpler–Kabataş magmatic complex and porphyry-epithermal Au deposit, East Central Anatolia, Turkey

The Çöpler epithermal Au deposit and related subeconomic porphyry Cu–Au deposit is hosted by the middle Eocene Çöpler–Kabata? magmatic complex in central eastern Anatolia. The intrusive rocks of the complex were emplaced into Late Paleozoic–Mesozoic metamorphosed sedimentary basement rocks near the northeastern margin of the Tauride-Anatolide Block. Igneous biotite from two samples of the magmatic complex yielded ⁴⁰Ar/³⁹Ar plateau ages of 43.75?±?0.26 Ma and 44.19?±?0.23, whereas igneous hornblende from a third sample yielded a plateau age of 44.13?±?0.38. These ages closely overlap with ⁴⁰Ar/³⁹Ar ages of hydrothermal sericite (44.44?±?0.28 Ma) and biotite (43.84?±?0.26 Ma), and Re–Os ages from two molybdenite samples (44.6?±?0.2 and 43.9?±?0.2 Ma) suggesting a short-lived (<1 my) magmatic and hydrothermal history at Çöpler. No suitable minerals were found that could be used to date the epithermal system, but it is inferred to be close in age to the precursor porphyry system. The Çöpler–Kabata? intrusive rocks show I-type calc-alkaline affinities. Their normalized trace element patterns show enrichments in large ion lithophile and light rare earth elements and relative depletions in middle and heavy rare earth elements, resembling magmas generated in convergent margins. However, given its distance from the coeval Eocene Maden–Helete volcanic arc, the complex is interpreted to be formed in a back-arc setting, in response to Paleocene slab roll-back and upper-plate extension. The tectonomagmatic environment of porphyry-epithermal mineralization at Çöpler is comparable to some other isolated back-arc porphyry systems such as Bajo de la Alumbrera (Argentina) or Bingham Canyon (USA).     

Impacts of Depositional Facies and Diagenesis on Reservoir Quality: A Case Study from the Rudist-bearing Sarvak Formation, Abadan Plain, SW Iran

An integrated geological-petrophysical analysis of the rudist-bearing sequence of the Cretaceous Sarvak Formation is given one giant oilfield, and provides an improved understanding of this main reservoir in the Abadan Plain, in the Zagros Basin, SW Iran. The main objective of this study is to evaluate reservoir potential of the Sarvak Formation, and then to utilize the calibrated well log signature to correlate reservoir potential in un-cored wells. Eight main facies are recognized and categori...     

Ophiolite emplacement by strike-slip tectonics between the Pontide Zone and the Sakarya Zone in northwestern Anatolia, Turkey

Northwestern Anatolia contains three main tectonic units: (a) the Pontide Zone in the north which consists mainly of the Gstanbul-Zonguldak Unit in the west and the BallLda<-Küre Unit in the east; (b) the Sakarya Zone (or Continent) in the south, which is juxtaposed against the Pontide Zone due to the closure of Paleo-Tethys prior to Late Jurassic time; and (c) the Armutlu-OvacLk Zone which appears to represent a tectonic mixture of both zones. These three major tectonic zones are presently bounded by the two branches of the North Anatolian Transform Fault. The two tectonic contacts follow older tectonic lineaments (the Western Pontide Fault) which formed during the development of the Armutlu-OvacLk Zone. Since the earliest Cretaceous, an overall extensional regime dominated the region. A transpressional tectonic regime of Coniacian/Santonian to Campanian age caused the welding of the Gstanbul-Zonguldak Unit to the Sakarya Zone by an oblique collision. In the Late Campanian, a transtensional tectonic regime developed, forming a new basin within the amalgamated tectonic mosaic. The different tectonic regimes in the region were caused by activity of the Western Pontide Fault. Most of the ophiolites within the Armutlu-OvacLk Zone belong to the Paleo-Tethyan and/or pre-Ordovician ophiolitic core of the Gstanbul-Zonguldak Unit. The Late Cretaceous ophiolites in the eastern parts of the Armutlu-OvacLk Zone were transported from Neo-Tethyan ophiolites farther east by left-lateral strike-slip faults along the Western Pontide Fault. There is insufficient evidence to indicate the presence of an ocean (Intra-Pontide Ocean) between the Gstanbul-Zonguldak Unit and the Sakarya Zone during Late Cretaceous time.     

铀在近代海洋生物中的积聚

本文研究的目的是确定软体动物对于铀在海洋生态系统中的分布所起的地球化学作用。对取自里海、日本海、马尔马拉海、爱琴海、黑海、地中海、波罗的海和印度洋的近代软体动物贝壳进行了生物地球化学研究,这些贝壳的物理、化学、地理和地球化学特征各不相同。本次研究中,分析了9个腹足类和54个双壳类不同种的贝壳以记录铀在不同季节层中的变化。季节层是由软体动物在整个生命过程中季节性的碳酸盐—有机相生成的。研究中使用的贝壳主要分3层:上(外)棱柱层,中棱柱层,内(珠母)层。此外,条件许可时,将贝壳性的头部、中部和下部分别进行分析,并且还计算出相对     

Automatic identification of fake patterns caused by short-width wavelets in seismic data

Despite the popularity of using the Haar wavelet filter in many applications, it sometimes introduces fake patterns into the multi resolution analysis (MRA) of seismic data. In this work, we compared different wavelet filters to demonstrate that these patterns are fake and not part of the original waveforms and to show that they are a result of using the Haar wavelet filter as a short-width wavelet. To achieve this, many seismic waveforms from two different sources: the Egyptian National Seismic Network (ENSN) and the High Sensitivity Seismograph Network Japan (Hi-net) are used with different wavelet filters. We propose an algorithm based on an autoregressive (AR) model to detect these patterns automatically and fully.