地質(zhì)工程翻譯試題電子版

1、2017碩士研究生專業(yè)英語試題地質(zhì)工程專業(yè)一、英譯漢(45分)Magmatic Ni-Cu sulfide deposits form as the result of segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma, and the partitioning of chalcophile elements into these from the silicate melt. Sufide saturation of a magma is not enough

2、in itself to produce an ore deposit. The appropriate physical environment is required so that the sulfide liquid mixes with enough magma to become adequately enriched in chalcophile metals, and then is concentrated iti a restricted locality so that the resulting concentration is of ore grade. The de

3、posits of the Norilsk region have developed within flat, elongate bodies (15 x 2 x 0.2 km) that intrude argillites, evaporites and coal measures, adjacent to a major, transcrustal fault and immediately below the centre of a 3.5 km-thick volcanic basin. Studies of the overlying basalts have shown tha

4、t lavas forming a 500 m-thick sequence within these have lost 75% of their Cu and Ni and more than 90% of their PGE. Overlying basalts show a gradual recovery in their chalcophile element concentrations to reach normal values 500 m above the top of the highly depleted zone.The ore-bearing Norilsk-ty

5、pe intrusions correlate with those basalts above the depleted zone that contain normal levels of chalcophile elements. The high proportion of sulfide (210 wt.%) associated with the Norilsk-type intrusions, the high PGE content of the ores, the extensive metamorphic aureole (100 400 m around the bodi

6、es), and the heavy sulfur isotopic composition of the ores (+8+12 a34S) are explicable if the ore-bearing bodies are exit conduits from high level intrusions, along which magma has owed en route to extrude at surface. The first magma to enter these intrusions reacted with much evaporitic sulfur, at

7、a low R value and thus gave rise to sulfides with low metal tenors. Successive flow of magma through the system progressively enriched the sulfides in the conduits, losing progressively less of their chalcophile metals, and thus accounting for the upward increase in metals in successive lava flows a

8、bove the highly depleted flows. The Voiseys Bay deposit lies partly within a 30100 m-thick sheet of troctolite, interpreted as a feeder for the 1.334 Ga Voiseys Bay intrusion, and partly atthe base of this intrusion, where the feeder adjoins it. Studies of olivine compositions indicate that an early

9、 pulse of magma through the feeder and into the intrusion was Ni depleted but that subsequent pulses were much less depleted. Trace element, Re-Os and S and O isotope data, and mineralogical studies indicate that the magma pulses interacted with country gneiss , probably principally in a deeper leve

10、l intrusion , extracting Si02, Na20, K20 and possibly sulfur form the gneiss, which accounts for the magma becoming sulfide saturated. The Jinchuan deposit of north central China occurs within a 6 km-Iong dyke-like body of peridotite. The compositions of olivine within the dyke, the igneous rocks th

11、emselves, and the ore are all inconsistent with derivation of the body from ultramafic magma, as originally supposed, and indicate that the structure forms the keel of a much larger intrusion of magnesian basalt magma. Flow of magma into the intrusion has resulted in olivine and sulfide being retain

12、ed where the keel was widening out into the intrusion. The West Australian komatiite-related deposits occur in thermal erosional troughs which have developed due to the channelisation of magma flow and the resulting thermal erosion of underlying sediments and basalt by the hot komatiite magma. The s

13、ediments are sulfide-rich, and may have contributed substantially to the sulfide of the ores. The mineralisation in the Duluth complex occurs in troctolitic intrusions along the western margin of the complex as a result of magma interacting with and extracting sulfur from the underlying graphite- an

14、d sulfide-bearing sediments.No magma flow channels have been identified so far, and the lack of magma flow subsequent to the development of sulfide immiscibility is regarded as the reason why these deposits are not of economic grade. When most major Ni-Cu sulfide deposits are compared, they prove to

15、 have a number of features in common; olivine rich magma, proximity to a major crustal fault, sulfide bearing country rocks, chalcophile element depletion in related intrusive or extrusive rocks, field and/or geochemical evidence of interaction between the magma and the country rocks, and the presen

16、ce of or proximity to a magma conduit. The features are thought to explain the three key requirements (sulfide immiscibilty adequate mixing between sulfides and magma, and localisation of the sulfides) discussed and have important implications with respect to exploration.二、漢譯英20分）金（Gold）是自然中主要以自然金屬形

17、式出現(xiàn)的元素。它常和銀形成合金，純的金是黃的，隨著銀的比例增加而變得發(fā)白。當(dāng)銀的比例增加到20%或以上時，這種合金叫做 銀金礦。雖然金是稀有元素，但是它卻廣泛分布在自然界中，在各種地質(zhì)條件下存在。 經(jīng)常在與花崗巖質(zhì)火成巖有關(guān)的含金石英熱液脈中發(fā)現(xiàn)金子。含金硫化礦物，最常見的 是黃鐵礦。在接近地表，因為它的對化學(xué)風(fēng)化有很強(qiáng)的抵抗能力，于是金子就從硫化物 中分離出來，它們既可以保留在土壤層中，或者被沖到附近的河流中形成砂金，因為它 有很高的比重19.3,金子就能通過砂礫落到河床底部的基巖的裂隙或下面的坑凹不平處。 砂金中發(fā)現(xiàn)過小金片或小金塊，結(jié)果導(dǎo)致1849年在加利福尼亞形成的淘金熱潮。其實在 世

18、界上最大的金礦產(chǎn)地，最初正是從砂礦中發(fā)現(xiàn)有金子存在的證據(jù)。砂金在整個地質(zhì)時 代都在形成，含金的礫石可以被較年青的巖石所掩埋，固結(jié)形成含金的礫巖。三、閱讀下列短文，并寫出150字左右的英文摘要(35分)Geology of Jinchuan Cu-Ni deposit, ChinaThe Jinchuan deposit is located in north central China, within but close to the southern margin of the Sino-Korean craton. It lies within one of a series of maf

19、ic-ultramafic bodies that intrude a marginal, north-west-trending, uplifted belt, the Longshoushan belt. Lower Proterozoic migmatites, gneisses, schists and marbles form a southeasterly facing monoclinal sequence, overlain to the southwest by Upper Proterozoic conglomerates, sandstones, limestones a

20、nd schists (Tang 1993). Major northwesterly striking faults bound and occur within the uplifted block, and the Jinchuan body occupies one of these which cuts Lower Proterozoic strata. Tang et aL (1992) cite a Sm-Nd age for the intrusion of 1.501土0.031 Ga.Chai and Naldrett (1992b) have concluded that

21、 the host intrusion was emplaced in a rift zone that formed at the boundary between the Sino-Korean craton and a developing Proterozoic ocean; this subsequently closed with the welding of folded Upper Proterozoic strata onto the craton. The host to the deposit comprises a mass of dunite lherzolite，o

22、livine websterite and websterite, 6500 m in length by a few m to500 m in width. It has a V-shaped cross section, tapering downward to pinch out at depths of500 1300 m. Northeast-trending faults offset different portions of the intrusion, which have been developed as separate mining blocks (Fig. 1).

23、The internal structure of the intrusion varies along its length, from block to block. At the northwest end internal contacts are steep (Fig. 1) with dunite predominating at depth, andlherzolite increasing toward the top, and forming thin marginal zones to the dunite at depth. In the central and sout

24、heastern parts of the intrusion, dunite is also predominant at depth, but layering between lherzolite, plagioclase lherzolite, websterite and olivine websterite is present, parallel to the margins at the margins but flattening and becoming horizontal close to the axis of the body (Fig. 1).The predom

25、inant ore types are net-textured ore in which olivine grains are enclosed in a continuous network of sulfide and lower grade disseminated oren in which sulfides occur both interstitial to silicate minerals and as discrete blebs. In general, dunite is the principal host to mineralisation, and essenti

26、ally all dunite is of ore grade. The nature of the magma responsible for the ultramafic body hosting the mineralisation (mafic or ultramafic) has been a source of controversy. Chai and Naldrett (1992a) have demonstrated using a plot of FeO versus MgO, that the liquid intercumulus to the olivine of t

27、he peridotites that constitute the intrusion contained 12 wt.% MgO and 11.5 wt.% FeO. When coupled with the other geochemical characteristics, such as the Ni/Cu ratio of 1.5 and the gabbroic-type PGE profiles (i.e. high (Pt+Pd)/(Ru+Ir+Os) ratios), this is strong evidence that the composition of the initial magma at Jinchuan was not ultramafic, but that of a magnesian basalt. Chai and Naldrett (1992a) proposed that the gabbroic cumulates which