The meteoritic origin of Tutankhamun's iron dagger blade

Scholars have long discussed the introduction and spread of iron metallurgy in different civilizations. The sporadic use of iron has been reported in the Eastern Mediterranean area from the late Neolithic period to the Bronze Age. Despite the rare existence of smelted iron, it is generally assumed that early iron objects were produced from meteoritic iron. Nevertheless, the methods of working the metal, its use, and diffusion are contentious issues compromised by lack of detailed analysis. Since its discovery in 1925, the meteoritic origin of the iron dagger blade from the sarcophagus of the ancient Egyptian King Tutankhamun (14th C. BCE) has been the subject of debate and previous analyses yielded controversial results. We show that the composition of the blade (Fe plus 10.8 wt% Ni and 0.58 wt% Co), accurately determined through portable x‐ray fluorescence spectrometry, strongly supports its meteoritic origin. In agreement with recent results of metallographic analysis of ancient iron artifacts from Gerzeh, our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects. Moreover, the high manufacturing quality of Tutankhamun's dagger blade, in comparison with other simple‐shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun's time.     

Primitive Ordovician (Floian) echinoderms from Sandu,Guizhou Province,South China,and their significance

Pelmatozoans diversified primarily during the Middle and Late Ordovician Period, with Early Ordovician records being much more limited, resulting in many gaps in our knowledge of the early stages of their diversification. Dissociated pelmatozoan ossicles have been found abundantly in one section in the Tonggao Formation (Tetragraptus approximatus Biozone, Floian, Early Ordovician). Most of the ossicles are thecal plates and stem ossicles from hemicosmitoid and glyptocystitoid cystoids. Thecal plates of ‘Cheirocrinus’ sp., Polycosmites sp., and other plates of uncertain affinity are described. A different ossicle type, Pentagonopentagonalis (col.), may represent crinoid remains; this would be one of the earliest occurrences of the class. The thecal ossicles and columnals are all considered, as both sets of data are desirable to determine the most complete estimate of generic diversity. The echinoderm ossicles may have been transported in from shallower water palaeoenvironments and clusters of ossicles may represent coprolites or regurgitates. Estimates of Early Ordovician palaeogeography that place this site at 30°S or near the palaeoequator are supported by the physiological requirements of the primitive echinoderms described herein. Copyright © 2014 John Wiley & Sons, Ltd.     

Mode of formation of the Nile Gorge in northern Egypt: a study by DEM‐SRTM data and GIS analysis

This is an overview of the mode of formation of the Nile Gorge in northern Egypt. It is based on the interpretation of the Shuttle Radar Topography Mission (SRTM) data along with detailed analysis of landsat image, geological map and seismic data. The results show that the current course of the Nile was caused by a differential uplift of two plateaus: Ma'aza, to the east, and Western Desert plateau, to the west of the river. This uplift is caused by dynamic forces resulting from subsurface convection processes. It also contributed to the formation of several drainage systems, basins and structural features. Abundant faults and fractures that are parallel to the Nile Valley on both flanks that are associated with uplift are proven to be contemporaneous with formation of the river. We conclude that understanding of the uplift is crucial to visualizing the Nile course and its geodynamic formation. The information derived from the SRTM data reveals invaluable knowledge in support of the presented remotely sensed geological features. The paper clearly explains the stages of formation of the Nile segments in space and time and structural controls on the path of the Nile River in Egypt. Copyright © 2015 John Wiley & Sons, Ltd.     

Geochemical characterization of Archaean amphibolites from the eastern part of Anshan–Benxi iron producing area,northeastern China: implication for tectonic setting of BIFs

The Anshan–Benxi iron producing area, which is located at the northeastern margin of the North China Craton, is the main distribution area of Archaean BIFs in China. In their eastern part, including the Gongchangling and Waitoushan deposits, BIFs mainly are hosted in the Archaean middle Anshan Group. Amphibolites are widely distributed in the iron‐bearing rock series, reflecting the tectonic setting of BIFs. Amphibolites not only have MORB‐like compositional characteristics, but also have island arc‐like ones, and they are consistent with back‐arc basin basalts (BABB). In the study area, the protolith of amphibolites belongs to Okinawa‐type BABB; it indicates that tectonic setting of BIFs is the intra‐continental back‐arc basin. In the study area, the formation of sedimentary basins for BIFs had been associated with oceanic plate subduction. Amphibolites from Gongchangling deposit are characterized by relative enrichments in LILE and LREE, and depletions in HFSE. This indicates that they had a relatively large influence of subduction in their formation. Amphibolites from Waitoushan deposit are characterized by relative enrichments in LILE without conspicuous depletions in HFSE, indicating relatively low subduction rates. Copyright © 2015 John Wiley & Sons, Ltd.     

Latest Devonian to earliest Carboniferous conodont and carbon isotope stratigraphy of a shallow‐water sequence in South China

To improve regional and intercontinental correlation of the uppermost Devonian–lowermost Carboniferous, we examined the conodont faunas and carbon isotopic records of the Tangbagou Formation in the Qilinzhai section, southern Guizhou, South China. The Tangbagou Formation is a succession of mixed carbonate–siliciclastic rocks that accumulated on a shallow‐water platform under normal marine conditions. Seven conodont zones for shallow‐water biofacies in South China, the Cl. gilwernensis–Cl. unicornis Zone, the Po. spicatus Zone, the Si. homosimplex Zone, the Si. sinensis Zone, the Si. eurylobata Zone, the Ps. multistriatus Zone and the Po. co. porcatus Zone in ascending order, are recognized in the Tangbagou Formation. Although apparently limited in its value for global correlation, this conodont zonation is more applicable to shallow‐water biofacies in South China. Carbonate samples have yielded carbon isotopic signatures consistent with those recorded in Euroamerica sections, in particular showing four distinct characteristics: (1) the peak values of Hangenberg Carbon Isotope Excursion (HICE) during the latest Devonian, (2) a minor positive shift (P1) in the Si. homosimplex Zone during the early Tournaisian, (3) a second minor positive shift (P2) in the Si. sinensis Zone and (4) the middle Tournaisian Carbon Isotope Excursion (TICE) in the middle part of the Tangbagou Formation. The similarity in peak values (~5.5‰) and magnitude of TICE for the Qilinzhai and Belgian sections indicates that the Euro‐asia δ¹³C_carb trends may reflect the changes in global mean ocean δ¹³C_DIC, rather than having been overprinted by local carbon cycling. Integration of conodont biostratigraphy and δ¹³C stratigraphy provides a powerful tool for stratigraphic correlation. Copyright © 2015 John Wiley & Sons, Ltd.     

基于ForcTT模型的牡丹始花期预测

选取山东菏泽市1981—2010年的牡丹始花期资料和气象资料,应用气候倾向率和Mann Kendall突变法等统计分析法探讨了牡丹始花期与气象条件的关系,利用ForcTT模型模拟了牡丹的始花期。结果表明：①随着气候变暖,菏泽牡丹始花期以4.4 d/10a的趋势逐年提前,并在1996年发生了一次突变。1981—1996年牡丹始花期主要集中在4月下旬,处于偏晚时期,1997—2010年始花期主要集中在4月中旬,有所提前。②牡丹花期发生的早晚主要受牡丹开花前1个月（3月）平均气温的影响,而且牡丹始花期和3月份平均气温的突变节点一致,其次是2月平均气温的影响,3月仅日照时数对牡丹花期有一定的影响,降水对牡丹花期无明显影响。③采用ForcTT模型预测牡丹的开花期时,最佳的开始日期为2月1日,最佳的基础温度为1 ℃时,平均误差为1.29天,最小偏差为1.73天,而当开始日期为2月1日,基础温度为3 ℃时的平均偏差和最小偏差均在2天之内,也再次验证了2月和3月的气温对牡丹始花期的影响较大。     

杭州湾北岸一次极端高温过程分析

利用实时探空场和欧洲中心20:00细网格、NCEP再分析资料对2013年8月6—10日杭州湾北岸极端高温过程进行分析,结果表明:副高脊线稳定在30°N、高层有辐散气流、低层26℃暖气团处于强副高中心影响是持续40℃极端高温发生的大尺度环流背景。副高与南亚高压"相向而行",在垂直方向上产生深厚的次级环流圈,是2013年极端高温持续时间长、影响范围大的一个重要因素。极端高温的出现与空气异常干燥有密切关系,北方高层干空气南下叠加在中低层副高暖干气团之上,从高层到近地层受一致下沉气流的绝热压缩增温,以及低空暖平流输送的综合影响,是导致7—9日杭州湾北岸多地最高气温屡破记录的原因。经检验,极端高温期间,业务参考使用的4个主要数值模式对最高气温的预报,EC模式误差较小且稳定,绝对误差为1℃,而GFS、JMA和T639误差分别达3℃、4℃和5℃,应用时需订正,以上结果可供夏季高温预报参考。     

一次江淮强暴雨过程的湿有效能量及其收支特征

利用高分辨率的WRF模式模拟结果,采用基于格点的湿有效能量计算方案,对一次江淮梅雨期强暴雨发生发展过程中湿有效能量的时空演变特征进行分析,并从定性和定量的角度探讨了能量方程转换项、平流项和垂直输送项对强暴雨过程中湿有效能量的输送和积聚作用。结果表明,强暴雨过程中湿有效能量的时空特征与强暴雨发生发展具有良好的对应关系,对流层低层800 h Pa湿有效能量40×104J·h Pa-1·m-2的等值线范围和该等值线伸展至500 h Pa附近可作为判断强暴雨发生的必要条件。暴雨发生前2~3 h的能量快速积聚及其对暴雨区移向的引导,对强暴雨预报具有良好的指示作用。湿有效能量的水平和垂直输送及转换确保了能量的积聚和对流层中层能量的增加,为强暴雨的发生和维持提供了充足的能量。