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the cenozoic
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  新生代
     Furthermore, the negative relationship between 143Nd/144Nd and 206Pb/204Pb, and the positive relationship between 87Sr/86Sr and 206Pb/204Pb suggest that the Cenozoic basalts in the studied area were generated from the intermediate-depleted asthenospheric mantle and EMII component.
     143Nd/144Nd与206Pb/204Pb之间的负相关关系和87Sr/86Sr与206Pb/204Pb之间的正相关关系说明本区新生代玄武岩起源于中等亏损程度的软流圈地幔,并与EMII富集地幔组分发生了混合。
短句来源
     The Cenozoic volcanic rock series consist of high-potassium calc-alkaline series and shonshonite series.
     新生代火山岩系包括高钾钙碱性系列和钾玄岩系列 ,高钾钙碱性火山岩形成于始新世 ,属于壳源岩浆系列 ;
短句来源
     The molybdenum conte nt of the Cenozoic mantle-derived xenoliths is in the range of 0.1~0.41 μg/g,averaging 0.19 μg/g.
     中国东部华北克拉通南缘和华南地块新生代地幔岩包体钼含量在0.10~0.41μg/g之间,平均含钼0.19μg/g;
短句来源
     They are rich in Cr_2O_3 and MgO and high in Cr/(Cr+A1), and knorringite and uvarovite molecules, but low in Fe_2O_3+FeO, Fe/(Fe+Mg), and grossular and almandine molecules as compared with those in the Cenozoic basalts of eastern China.
     它们与我国东部地区新生代玄武岩中的镁铝榴石相比,前者Cr_2O_3及MgO含量、Cr/(Cr+Al)比值,镁铬榴石分子和钙铬榴石分子高; 而Fe_2O_3+FeO含量、Fe/(Fe+Mg)比值,钙铝榴石分子及铁铝榴石分子低。
短句来源
     The Cenozoic kamafugites in Lixian County of West Qinling are poor in SiO 2 and Al 2O 3 but rich in MgO, CaO, TiO 2 and K 2O+Na 2O. The modal mineral assemblage is composed mainly of olivine, clinopyroxene, nepheline/ kalsilite, melilite/leucite and Ti_phlogopite.
     西秦岭礼县地区新生代钾霞橄黄长岩系具有贫SiO2 、Al2 O3,富MgO、CaO、TiO2 及K2 O +Na2 O的特征 ,矿物组合中除橄榄石、透辉石外 ,普遍含有霞石 /钾霞石、黄长石 /白榴石和钛金云母等矿物。
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  “the cenozoic”译为未确定词的双语例句
     The Cenozoic period can be divided into three evolution steps (Es 4 +Ek, Es 2+Es 3, Es 1+Ed), based on their characteristics of deposition and structural development.
     其中早第三纪阶段又可依据沉积、构造发育特征分为Es4+Ek ,Es2 +Es3 和Es1+Ed 3个演化时期。
短句来源
     The ratios of 206Pb/ 204Pb varied from 18.670 to 18.808, 207Pb/ 204Pb from 15.614 to 15.784, respectively. The sulfur and lead isotopic compositions were similar to that of the Himalayan porphyries and porphyry-type deposits in western Yunnan, which comprehened the Cenozoic magmatic activity and mineralization occurring in Hongshan area.
     铅同位素206Pb/204Pb和207Pb/204Pb比值分别为18.670~18.808和15.614~15.784,其硫、铅同位素组成与滇西地区喜马拉雅期斑岩和斑岩矿床的硫、铅同位素组成相似,暗示红山矿区有新生代的岩浆活动和成矿作用。
短句来源
     Laojunshan syenite lies in the south segment of the Cenozoic potassic alkaline magmatic rock in Ailaoshan-Jinshajiang river. The SHRIMP zircon U-Pb dating results of Laojunshan Syenite are 34.8±1.6Ma(2σ),MSWD=0.38(probability= 0.96), which is consistant with the Oligocene epoch, belonging to Himalayas period.
     老君山正长岩锆石SHRIMP定年结果为34.8±1.6Ma(2σ),MSWD=0.38(可信度为0.96),相当于渐新世,属于喜马拉雅期。
短句来源
     The structural characteristic of the North Ordos basin in the Late Mesozoic and the Cenozoic is researched with the data of seismic,geological and former achievements.
     根据地震、地质等资料,结合野外地质及前人研究成果,对鄂尔多斯盆地北部中生代晚期以来后期改造特征进行了研究。
短句来源
     The megacrystalline and macrocrystalline phlogopites from the Cenozoic volcanic rock of Western Qinling are of the early crystallization phase under the conditions of some 1300O℃,30×l0 ̄8pa,and rich CO_2 and H_2O in the mantle.
     巨晶和粗晶金云母是在>1300℃,30×10 ̄8pa,富CO_2和H_2O的条件下的早期结晶相。
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  相似匹配句对
     CENOZOIC HISTORY OF BAIKAL DEPRESSION
     贝加尔凹陷的新生代历史(英文)
短句来源
     CENOZOIC VOLCANOES AND VOLCANICS IN ITALY
     意大利新生代火山及火山岩——访意大利地质考查报告
短句来源
     The Cenozoic strata are developted in the depression.
     在该凹陷内发育了 10 0 0 0余米厚的新生代地层。
短句来源
     Structural Evolution of Cenozoic of the Okinawa Trough
     冲绳海槽新生代构造演化讨论
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  the cenozoic
The Role of Antarctica in the Formation of the Cenozoic Climate and Contemporary Open Sea Abyssal Fauna
      
Cluster analysis was used to compare species composition of marine and brackish water bivalves in the Cenozoic deposits of the Russian Far East, Hokkaido, and California.
      
In terms of placer productivity during the Phanerozoic, the second half of the Paleozoic ranks below the Cenozoic megaepoch.
      
New Data on the Cenozoic History of the Underwater Yamato Rise, Sea of Japan
      
During the Cenozoic, the entire Sea of Japan depression experienced a submergence.
      
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Ⅰ. The Yinshan district as an example of "activizing region" in the Chinese platform One of the most typical localities that show clearly the phenomenon of"activization of platform" (активи. зация платформы) is the Yinshan region, aneast western mountain range on the border between the North-China plain andthe Mongolian plateau. It has long been recognized as a platform because ofthe presence of a folded foundation Pre-Sinian in age. However, owing to thefacts that Mesozoic crustal movements and magmatic activities...

Ⅰ. The Yinshan district as an example of "activizing region" in the Chinese platform One of the most typical localities that show clearly the phenomenon of"activization of platform" (активи. зация платформы) is the Yinshan region, aneast western mountain range on the border between the North-China plain andthe Mongolian plateau. It has long been recognized as a platform because ofthe presence of a folded foundation Pre-Sinian in age. However, owing to thefacts that Mesozoic crustal movements and magmatic activities are importantwithin this area, some geologists including G Schoenmann, hold that it is ageosynclinal region. It is Ю. М Шейманн who first noticed the phenomenon of activizationappearing in the Chinese platform. В. М. Синицын in his "Строенив и развитиекитайской платформы" indicates that some of the mountain ranges includingYinshan, which have been formerly referred to the folding belts developingfrom geosynclines, are in fact the internal structures of the Chinese platform. In this paper the writer after the opinion of В. М. Синицын, assigns theYinshan area as one of the "activizing regions" in the Chinese platform, andgives more detailed descriptions and discussions mainly on the point of thehistory of its stratigraphic development. Really it is a fact that the Yinshan region has an old folded foundationwhich is composed of metamorphic complex including chiefly gneisses, schists,and old granitic intrusions apparently Pre-Sinian in age. Since the formationof this folded foundation during the Luliang movement (=Goto-Karelian mo-vement), the old land of the Yinshan region has "activized" or "resurrected"several times. As early as in the Sinian period, a depression prolonging in E-Wdirection happened on its southern border, where Sinian limestone 900 metresin thickness and in some places up to 9,620 metres was so deposited. During a long time of the Palaeozoic era, the Yinshan old land was in the poriod ofdenudation except some Cambrian marine limestones only 144 metres in thick-ness deposited in the western part. At the end of the Palaeozoic era, local acti-vization with the formation of continental basin-deposits of Permian age, up to1,380 metres in thickness, as found in the Tachingshan area again happened.In the middle Mesozoic era, the Yinshan region came to a period of strongactivity. Structural depressions duo to "Процесс аркогенеза" occurred universallywithin the whole area and magmatie activities in large magnitude associatedthis crustal movement, so that a great sequence of freshwater basin-depositswith intercalations of volcanic beds, up to 8,000 metres in total thickness wereformed. During the formation of these strata, especially at the end of Mesozoic,interruptions of depositon happened frequently, folds and thrusts were abund-antly formed, and intrusive bodies of "young granite" were produced hereand there. In the Tertiary period, the Yinshan region was violently faulted, andvolcanic activities still happened, producing the basalt lava flow spreading ina wide area. The activity of the Yinshan old land has not ceased even to-dayas shown by the facte that its whole area is in the process of uplift and by thepresence of an earthquake zone known in the historical time. Ⅱ. To what Geotectonic Unit does the Southeastern Coastal Region of China Belong? On the Southeastern coast of China there is a district where geotectoniccharacteristics have never been recognized clearly. It is A. W. Grabau who firstreferred it to an old land named "Cathaysia". J. S. Lee holds the same opinion.In his geotectonic map of China, B. M. Синицын also assigns this region to aplatform and marks it as a part of his "Южно-китайский платформенный массив".However, there is still another opinion opposed to this. A. C. Хоминтовский, forinstance, renders recently this district to a geosynclinal region and proposes thename "Minche Pacific folding zone" for it. H. T. Yang and T. Y. Yu agreewith him. In the year 1954, the writer in his compilation-work connected with thegeology of Fukien and Kwangtung, found that the geotectonic characteristics ofthe southeastern coastal region of China are not only unagreeable with thosefound in a common platform on the one hand, but also contrasting, with thoseof a geosynclinal region on the other. In fact, it cannot be referred suitably toany geotectonic unit except to the intermediate type as shown by the history ofits geological development. Apparently it is an "activizing" or "resurrected" platform. During the Pre-Sinian crustal movement (the Luliang movement), a foldedfoundation composed of old gneisses, schists, and phyllites was completely for-med. Obviously this is a part of the broad old land of Southern China. In the earlier stage of the Palaeozoic era, the whole area of this region wasexposed in the air and under denudation. Hence, no deposit of any kind wasformed. After the Caledonian movement, depressions happened in the western partof this region, where the Devonian-Lower carboniferous continental deposit, theNanching series consisting mainly of quartzite, conglomerate and shale has beenformed, but the other parts were still under denudation. These facts show thatthis region was still a land at that time. Uralian and Lower Permian limestones, known respectively as the Chuan-shan limestone and the Chihsia limestone, separated from each other by adisconformity, spread widely in this region. This indicates that the marine trans-gressions really happened in the southeastern coastal region of China. However,the thicknesses of these limestones (only 30 metres and 150 metres respectively)and their uniformity in the horizontal direction show that the sea at thosetimes was shallow, and the magnitude of subsidence of the earth crust withinthis region was small. The unnoticed lateral changing of lithological charactersof these limestones proves the same fact. Undoubtedly these limestones arenothing but the marine deposits of platform-type. From Upper Permian toTriassic, this region was under a condition of alternation of transgression andregression of the sea. Owing to the fact that the amplitude of oscillation of theearth crust of this region at that time was small, the deposits formed duringthe marine transgression were thin and interrupted again and again by disconfor-mities (or even unconformities). Sometimes continental deposits are intercalated. Since the later period of Triassic, the southeastern coastal region has neverbeen covered by the sea again. And, a new condition began to happen in LowerJurassic. Here, the old land became to "resurrected", so that a series of depres-sing belts were formed as a result of "Процесс аркогенеза". In association withthe subsidence of these depressions, continental beds with a total thicknessup to 3,000 metres were deposited. In the beds interruptions frequently occurred.Folds were abundants, although they or at least some of them were intermediatetype. At the same time, magmatic activities were significant. Itappearedfirstly in the form of volcanic eruptions as recorded by a great sequence of beds consisting of tuff and rhyolite intercalating in the continental bedsmentioned above. And then, at the end of the Mesozoic, numerous graniticbodies were produced. Coming to the Cenozoic era, this region still sufferedfrom rather strong crustal movements accompanied by basalt lava eruptions. Theactivity of the old land has not yet been ceased even to-day as marked by thepresence of a famous earthquake zone between Kwangtung and Fukien, and theabundance of hot springs which widely spread within this region. All theseshow the typical characters of an "activizing" or "resurrected" platform. Final-ly, the complexity of the types of mineral deposits found in Fukien and Kwang-tung also proves the geotectonic nature of this region. Summarizing the whole matter, we may say that the southeastern coastalregion of China was originally an old land. Although it has been agian andagain submerged by the sea, the resulting marine deposits are entirely differentfrom those of geosynclinal region. In the middle of Mesozoic, this region beganto be active violently again, producing a series of depressions or "secondarygeosynclines", in which thick continental beds were deposited, and, at the sametime, folds of intermediate type, serious volcanic eruptions and magmatic intru-sions were produced. Hence, to refer the southeastern coastal region of China toan "activizing" platform is quite strongly proved. The northwestern boundary of this "activizing" platform is generally onthe line starting from central Chekiang through central Kiangsi to the Sou-thwestern part of Kwangtung, because the history and characteristics of geolo-gical development of the Southeastern Kiangsi and Central-southern Kwangtungare quite similar to those of Fukien and Eastern Kwangtung. As to the nomination of this geotectonic unit, the writer proposes to callit "Cathaysian activizing region". This name is derived from the "Cathaysia"of A. W. Grabau but adds, according to necessity, the meaning of activizing or"resurrected" characters of this region. The so-called "Minche Pacific foldingzone" of A. C. Хоминтовский is obviously unacceptable because it entirely doesnot coincide with fact. Compared with the "aetivizing" platforms found in other parts of theworld, the Cathaysian coastal "activizing" platform has its own characteristics,especially shown by the presence of numerous, widely spread, small depressionsor "secondary geosynclines", and the acidic magmatic activities appearing on alarge scale. All these indicate that this is a special type differing from all theknown "activizing" plat

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Ⅰ. General SKETCH The Cenozoic basalt lavas are widely distributed along the coastal regionand its adjacent districts in eastern China. They form either widespread plateausor scattered mesa-like hills; and, in some places, the volcanic craters are stilladmirably preserved to-day. These basalt sheets were erupted extensively in lateTertiary and early Quaternary times. They belong to the multiple-vent basalts,but not the plateau basalt in the type of eruption. In this paper are given the results of a petrochemical...

Ⅰ. General SKETCH The Cenozoic basalt lavas are widely distributed along the coastal regionand its adjacent districts in eastern China. They form either widespread plateausor scattered mesa-like hills; and, in some places, the volcanic craters are stilladmirably preserved to-day. These basalt sheets were erupted extensively in lateTertiary and early Quaternary times. They belong to the multiple-vent basalts,but not the plateau basalt in the type of eruption. In this paper are given the results of a petrochemical study of the Ceno-zoic basalt in eastern China. Geological and petrographical studies of the basaltsare not described in detail. Judging from the chemical compositions, the mostoutstanding characteristic feature of the most basaltic rocks is the richness inalkalis, especially in K_2O, also the undersaturation in silica, and, therfore,the most of the basalts distinctly belong to the alkaline rock suite. Such chemicalcharacters are closely related to modal compositions. The general petrogra-phical characters of the basalt may be now as well described. In North Chinaand South Manchuria most basalts are trachy basalt and its allied types, andoccasional nepheline basalt. The constituent minerals of these basalt are cha-racterized by the presence of anorthoclase, potash-adesine, plagioclase, titanaugite,as well as by the abundance of olivine. In South China the main basalt is olivinebasalt, consisting of olivine, augite, and plagioclase as usual. At some placesthe basalt may be slightly silica saturated that the occasional presence of hyper-thene and quartz (xenocryst) is noteworthy. In North Manchuria the dominant basalt is leucite basalt, containing leucite and olivine as phenocryst and groundmass constituent. Xenocryst of quartz and feldspar grains are sometimes present.In Taiwan Province, basalt of Kuanyinshan volcano is of the tholeiite type,but, in some other districts, the alkaline basalt with feldspathoidal constituentalso occurs. In view of the above-mentioned facts, the petrographical difference seemsto be matched by the differences of the major tectonic forms of China. Thesefacts may be tabulated below: Geographical region Tectonic forms Basalt type 1. North Manchuria Granitized region in Varisclde Leucite basalt 2. North China & South Precambrian Sino-Korean Trachybasalt Manchuria massive 3. South China Huanan platform in Yenshanide Olivine basalt 4. Taiwan Himalayide Tholeiite basalt Ⅱ. Regional INVESTIGATION In Table 1 the chemical analyses of the Cenozoic volcanic rocks in easternChina published up to 1951 were collected, of which 74 analyses are basalticrocks. The available analyses of every basalt sheet are taken an average to re-present the regional composition of the basaltic rocks. The localities of the basaltsheets where the analyzed chemical data are referable are shown in Figure 1.In all, 21 localities of basalt are investigated. The average chemical compositionsof each basalt locality, together with the normative minerals, Niggli's valuesand Zavarickij's numbers are given in Tables 2 A and 2 B respectively (localnos. in Table 2 correspond to the numerous in circle in Figure 1). For theconvenience of comparison, the average chemical composition of some standardbasalts (after S. R. Nockolds, 1954), some alkaline basalt in New Zealand (afterW. N. Benson, 1944) and Uganda (after A. Holmes, 1937), and the world's ba-salts, together with the normative minerals, Niggli's values and Zavarickij'snumbers of our calculation, are selected and given in Tables 3A, 3B, 7A, 7Brespectively. As mentioned above, the chemical composition of eastern China basalt ischaracterized by the high content of alkalies, and especially the K_2O. This cha-racter is definitely revealed by the normative feldspar, which is given in Table2 A and graphically shown in Figure 2. From this graphical representation,it is recognized that the normative feldspar becomes increasingly enriched ormolecular from South China to North Manchuria. Although the projected points appear to be scattered, a trend of clustering of the normative feldspars in accor-dance with its geographical distribution is apparent upon close inspection. Inthe normative pyroxene diagram, Figure 3, it is shown that most basalts of easternChina are rich in Wo molecular, falling near the Di-Hd line; On the otherhand, those of Kuanyinshan basalts of Taiwan Province are poor in Wo andcluster in the central part of the Di-Hd-Fs-En field. Therefore, that the easternChina basalt, excluding that of Kuanyinshan, belong to the alkaline rock suiteis justified. The comparison diagrams of qz, al-alk, C-(al-alk) and K-mg ofNiggli's values, based on the data given in Tables 2 B, 3 B, and 7 B, are gra-phically shown in Figs. 4, 5, 6 and 7 respectively. As will be seen from thesefigures, in general, the qz and al-alk of Niggli's value are lower, but C-(al-alk) and K-mg are higher than those of some common basalts. Fig. 8 isZavorickij's petrochemical vector diagram, from which the petrochemical cha-racters of high alkaline property in eastern China basalts are clearly justified. Ⅲ. Serial COMPARISON For ascertaining and understanding the general chemical characters, theCenozoic eastern China basalt and its differentiated associations are divided,based on the SiO_2 content, into 5 chemical types, the average composition ofwhich is given in Table 5A. As the chemical composition of Kuanyinshanvolcanic rocks in Taiwan Province shows a distinct calc-alkaline affinity, it is,therefore, dealt with the same procedure as well. The average chemical compo-sition of the volcanic rocks is given in Table 5 B. Since the Cenozoic basalt ineastern China covers the region adjacent to the Circum-Japan Sea and the Ja-panese Archipelagoes which are well known by the occurrence of alkaline andcalc-alkaline rock suite respectively. The serial variation in the chemical com-position of eastern China volcanic rocks is examinated in comparing them withthose of the Circum-Japan Sea and the Japanese volcanic rocks. The data usedfor the Circum-Japan Sea and Japanese rocks, which are given in Tables 6 A and6 B, are based on Tomita's and Yamada's calculated results respectively. Zavaric-kij's number of the same rocks, based on Zavarickij's data, is given in Table6 C. Following various petrochemical methods, some graphic diagrams are cons-tructed in order to express the chemical characters of the rock series of easternChina more definitely. The difference in chemical composition as comparedwith the Circum-Japan Sea alkaline rock suite is shown in the normal varia-tion diagram Figure 9. Other petrochemical indices (proposed by Peacock, Hol- mes and Tomita respectively) obtained are summarized below: Ⅰ Ⅱ Ⅲ Ⅳ alkali-lime index (Fig. 10) 65.5 59.0 63.0 52.0 alkali-alumina index (Fig. 11) -- -- 67.8 63.3 Ol-Q index (Fig. 12) 20.0 43.0 72.5 76.5 Ne-Hy index (Fig. 13) -- -- 55.0 59.9 Di-C index (Fig. 14) 46.5 46.5 -- -- Ⅰ. Japanese volcanic rocks; Ⅱ. Taiwan volcanic rocks; Ⅲ. Circum-Japan Sea alkaline suite; Ⅳ. eastern China volcanic rocks.From these graphical solutions in Figs. 10-14, it may be justified that thevolcanic rocks in eastern Asia have increasingly enriched the alkali contentfrom the Japanese Archipelagoes to the mainland of China. Figure 15 is avariation diagram of the normative feldspar of the eastern China series, incomparison with that of the Circum-Japan Sea region, the Japanese Archipela-goes and New Zealand. As will be seen from the diagram, the variation of thenormative feldspar of eastern China rock series is quite discriminative. Notonly is it richer in or molecular, but the positions of point N and O (corres-pond to the respective Ol-Q and Ne-Hy indices as shown in Figs. 12 and 13)of the eastern China series are also in a later course than the others. Figure 16is a paragenetic diagram of the normative plagioclase and pyroxlene of theeastern China series. In the variation diagram of the normative pyroxene, Fig.17, the distinct difference in the course of variation between the alkaline andcalc-alkaline series is clearly revealed. In this connection, the directon of varia-tion in the normative pyroxene of the alkaline series differs from that of thecalc-alkaline series. It is also notable that the range of variation in the easternChina series is smaller, due to the presence of higher Wo molecular in bothbasic and acidic types, as compared with that of the Circum-Japan Sea series.Figure 18 is Zavarickij's petrochemical vector diagram of the eastern Chinaseries compared with that of Circum-Japan Sea and Japanese series. It may be acomplemental diagram of the serial comparison diagram of eastern Asia volcanicrock series, prepared by Zavarickij (cf. A. N. Zavarickij's Introduction to Petro-chemistry of Igneous Rocks, 1950, Fig. 61, p. 205, in Russian). The distinctdifference of these rock series may be clearly observed in the graphical solution.In Table 7 A is given the average chemical composition of eastern China basalt,together with the composition of basaltic rocks of the world (including olvinebasalt and Toleiite, Ocean basalt and Continent basalt) for comparison. Theeastern China average is very similar to the average composition of the olivine- basalt of the Circum-Japan Sea region (based on Tomita, 1935, and recalculatedby the writer), while it differed more or less from that of any of the world'sbasalts by the high content of alkali and especially K_20. This character isdefinitely revealed by the normative feldspar and pyroxene, which are graphi-cally shown in Figs. 19 and 21 respectively. Figure 20 is Zavarickij's petroche-mical diagram of the world's basalt. As shown in these diagrams, it suggests atransitional relation rather than a sharp cleft in the petrochemical charactersof the world's basalts. There are no distinct types of basalt magma but rathera continuous series from silica saturated (tholeiitic) to silica-undersaturated(olivine-basalt) rock, although the chemical distinction may be too subtle to beread directly from chemical analyses. Ⅳ. ORIGINAL Basalt Magma The original magma of eastern China basalt belongs to the olivine basaltmagma type. In this discussion it is assumed that the primary olivine basaltmagma is melted from a crust of peridotitic crystalline rock in the upper partof the sima layer. Olivine basalt magma may be modified by the gain of alimited amount of silica and some alkalies to produce a derived melt, whichappears to coincide with the

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This paper investigates from petrochemical and mineralogical point of view the Cenozoic basaltic rocks in Kiangsu and Eastern Anhwei Province. It is determind that as a whole they belong to alkali basaltic series. They were the products of the early-, middle- and late- magmatic cycles of Himalayan movement. These rocks consist of olivine basalt, alkali olivine basalt, basanite and nephelinite, together with alkali diabase, tholeiitic diabase and analcite syenite which have been formed as a result of differentiation...

This paper investigates from petrochemical and mineralogical point of view the Cenozoic basaltic rocks in Kiangsu and Eastern Anhwei Province. It is determind that as a whole they belong to alkali basaltic series. They were the products of the early-, middle- and late- magmatic cycles of Himalayan movement. These rocks consist of olivine basalt, alkali olivine basalt, basanite and nephelinite, together with alkali diabase, tholeiitic diabase and analcite syenite which have been formed as a result of differentiation and contamination. The "alkali degree" of the later basaltic rocks is higher than the earlier, and that of the rocks in the western region is also higher than the eastern. Although most basalts have somewhat similar composition, but due to fractional crystallization and contamination there occurs a series of regular changes in petrochemistry and mineral composition. This paper also attempts to estimate the depth of magma chamber on the basis of the types of basaltic magma and composition of ultramafic inclusions and augite, anorthoclase, garnet megacrysts. There is no doubt to believe that from east to west in this region the depth of magma chamber increased from 35~50 km to 75~90 km ca.

本文从岩石化学和矿物学角度,研究了江苏及皖东新生代玄武质岩石,初步确定它们属于碱性玄武岩系列;是喜山运动早、中、晚三个岩浆旋迥的产物;主要岩石类型有橄榄玄武岩、碱性橄榄玄武岩、碧玄岩、霞石岩以及由分异作用或混染作用形成的碱性辉绿岩、拉斑辉绿岩和方沸正长岩;岩石的碱性程度自老至新、自东向西增强;由于岩浆的分离结晶作用和受硅铝层混染,引起一系列岩石化学和矿物成分的规律性变化。本文还试图根据玄武质岩浆类型和包裹的超镁铁包体,以及普通辉石、歪长石、石榴石大晶体的成分,估计岩浆源的深度,自东向西由35~50公里加深到75~90公里左右。

 
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