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1.
The effect of light intensity ( 1500 Ix and 5000 Ix) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211 ), Phaeodactylum tricornutum (Bl14, Bl18 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated.The total lipids of B13, Bl14, and B211 grown at 5000 Ix were lower than those grown at 1500 Ix. No evident changes were observed in Bl18, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:l(n- 7) and 20:5(n-3) . Cylindrothecafusiformis had high percentage of 20:4n - 6 (9.2 - 10.9% ) . The total polyunsaturated fatty acid /rl all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis. 相似文献
2.
Summary Upper amphibolite facies gneisses in the southern Indian Shield show local transformation into veins, clots and patches of orthopyroxene-bearing dry granulites (incipient charnockites). Depending upon the protolith composition, these desiccated zones are classified into ortho- and para-charnockites and have developed within rocks of distinct mineralogy and chemistry at different time intervals through the structurally-controlled influx of carbon dioxide-rich fluids. Our geochemical investigations at five critical quarry sections indicate that the incipient charnockites have undepleted chemistry and very low K/Rb values. In the paracharnockite localities, where granulite formation is characterized by consumption of garnet, biotite and quartz to produce orthopyroxene, loss of Rb and Ba and enrichment of Ti are observed. In contrast, the orthocharnockite localities show marked LILE enrichment with gain of K, Rb and Ba and loss of CaO, suggesting extensive replacement of plagioclase in the gneisses by K-feldspar in the charnockite through K-Na-Ca exchange reactions with influxing carbonic fluids. The marked depletion in Fe, Mg, Ti and P in these rocks correlates with progressive dissolution of hornblende, biotite, magnetite and accessory apatite. Our study indicates that gneiss to granulite transformation, even if on a local scale, is not an isochemical phenomenon, but attended by distinct element mobilities, although they are contrastingly different from the geochemical trends in some regional high grade terrains.
Geochemie von Gneiss-Granulit-Übergängen in den Incipient Charnockite Zonen von Süd-Indien
Zusammenfassung Gneise der oberen Amphibolit-Fazies im Südteil des Indischen Schildes zeigen lokal Umwandlungen in Adern, and unregelmäßigen Bereichen von orthopyroxen-führenden trockenen Granuliten (Incipient Charnockites). In Abhängigkeit von der Zusammensetzung des Ausgangsgesteins werden diese Zonen in Ortho- und Paracharnockite eingeteilt. Sie entwickelten sich in Gesteinen von charakteristischer mineralogischer und chemischer Zusammensetzung zu verschiedenen Zeit-Intervallen durch die tektonisch kontrollierte Zufuhr von kohlendioxid-reichen Fluiden. Unsere geochemischen Untersuchungen an fünf strategisch ausgewählten Steinbruchen zeigen, daß die Incipient Charnockite eine nicht verarmte chemische Zusammensetzung und sehr niedrige K/Rb Werte haben. In den Paracharnockit-Lokalitäten, wo Granulitbildung charakterisiert wird durch das Verschwinden von Granat, Biotit und Quartz, aus denen Orthopyroxene gebildet werden, ist Verlust von Rb und Ba und Anreicherung an Ti zu beobachten. Im Gegensatz dazu zeigen die Orthocharnockite eindeutige LILE Anreicherung mit Zunahme von K, Rb, und Ba und Verlust von Ca0. Dies weist auf extensiven Ersatz von Plagioklas in den Gneisen durch K-Feldspat in den Charnockiten durch K-Na-Ca Austausch-Reaktionen mit zugeführten C02-Fluiden hin. Die deutliche Verarmung an Fe, Mg, Ti und P in diesen Gesteinen wird mit zunehmender Auflösung von Hornblende, Biotit, Magnetit und akzessorischem Apatit erKlärt. Unsere Untersuchungen zeigen, daß die Gneis-Granulit Transformation auch im lokalen Maßstab nicht ein isochemisches Phänomen ist, sondern durch charakteristische Elementtransporte charakterisiert wird. Diese unterscheiden sich jedoch deutlich von den geochemischen Trends, die in einigen regional-metamorphen high grade terrains zu beobachten sind.[/p]相似文献
3.
Controlling geological and hydrogeological processes in an arsenic contaminated aquifer on the Red River flood plain,Vietnam 总被引:1,自引:0,他引:1
4.
5.
十四株海洋微藻脂肪酸组成的研究 总被引:5,自引:0,他引:5
对 4个门的 14株 (红藻门 8株 ,甲藻门 1株 ,隐藻门 2株 ,绿藻门 3株 )海洋微藻进行了脂肪酸含量测定 ,微藻在确定的条件下生长 ,指数生长末期收获。结果表明 ,各门的微藻都有其独特的脂肪酸特征 :红藻中含有大量的 2 0 :4 n- 6和 2 0 :5n- 3,其中紫球藻 R2 5含量最高 ,占总脂肪酸的4 9.8% (AA占总脂肪酸的 2 0 .5% ,EPA占总脂肪酸的 2 9.3% )。隐藻的主要脂肪酸是 16 :0、18:1n- 9、18:3n- 3、18:4 n- 3、2 0 :5n- 3、2 2 :5n- 3。与其它甲藻有别的虫黄藻 ,18:4 n- 3含量很少并且不含EPA,其主要合成的是 16 :0、18:1n- 9和 2 2 :6 n- 3。 C16和 C18的不饱和脂肪酸是本实验研究的 3株绿藻的主要脂肪酸 相似文献
6.
小营盘金矿赋存在稳定的缓倾斜石英脉中,但单纯的白色石英脉仅有微弱矿化,只有经过S懊断层剪切拉张破裂和叠加铁白云石化及硫化物蚀变的石英脉才能成为矿体,金矿体的顶底面常被铁白云石蚀变岩和糜棱岩所包裹,而且部分蚀变岩的金含量也达到工业品位,石英脉与蚀变岩作用构成矿体。因此,早期金成矿作用的时代大致与铁白云蚀变同期,含金铁白云石蚀变岩的δ^13C值平均为-4.13‰,Pb-Pb等时线年龄为2711±238 相似文献
7.
2003年“雪龙号”北极科学考察期间,对沿途海洋大气进行采样,分析其中气相多环芳烃的空间分布。结果显示,气相中主要是2-4环的多环芳烃,其中菲为主要的化合物,平均占到总多环芳烃的55.1%。在整个航程的广泛区域尺度内,气相总多环芳烃浓度在1043.9-92993.1pg/m3。空间分布上,远东亚的海面>北太平洋海面>北极圈以内海面;总多环芳烃的浓度随纬度升高呈现显著降低的趋势。通过Clausius-Clapeyron方程对浓度和温度相互关系的分析表明,温度是控制气相多环芳烃长距离传输的主要因素。 相似文献
8.
9.
Qiao Xiufu Song Tianrui Gao Linzhi Peng Yang Li Haibing Gao Mai Song Biao Zhang Qiaoda 《《地质学报》英文版》1994,7(3):243-265
Abstract On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as escaped structure of micrite veins and liquefied deformation formed in the period of seismic liquefaction, land subsidence structure after liquefaction, tsunamic hummocky and turbidite produced by seismic events, This sequence is a generalization and summation of field observation in vast areas, which shows the whole process of a strong seismic event and provides an unified theoretical explanation. The pattern of the seismic sequence by vibrational liquefaction provides one of correlation standards for geologists in the field to discriminate events in carbonate sequences. Based on the pattern of seismic sequence, the authors first advance a new conception of the Palaeo - Tanlu (Tancheng - Lujiang) Zone and discuss primarily its geological significations. 相似文献
10.
G. Hillers P. M. Mai Y. Ben-Zion J.-P. Ampuero 《Geophysical Journal International》2007,169(2):515-533
We perform a systematic parameter space study of the seismic response of a large fault with different levels of heterogeneity, using a 3-D elastic framework within the continuum limit. The fault is governed by rate-and-state friction and simulations are performed for model realizations with frictional and large scale properties characterized by different ranges of size scales. We use a number of seismicity and stress functions to characterize different types of seismic responses and test the correlation between hypocenter locations and the employed distributions of model parameters. The simulated hypocenters are found to correlate significantly with small L values of the rate-and-state friction. The final sizes of earthquakes are correlated with physical properties at their nucleation sites. The obtained stacked scaling relations are overall self-similar and have good correspondence with properties of natural earthquakes. 相似文献