Random wave-current interactions in water of varying depth

Refraction of incoherent random gravity waves with currents and bottom topography results in spatial variations in the spectral characteristics of the free surface. Prediction of such variations based on the radiation transfer equation is in a simple analytic form for the case of one dimensional inhomogeneities in currents and topography. This analytic form is examined in terms of two-dimensional wave number- and polar frequency-direction spectra along the associated dynamic and kinematic constraints relevant to wave breaking and reflection. Results are specialized to the simplest case of horizontal shear currents in deep and shallow water with explicit examples to illustrate the relative and combined effects of currents and topography on free surface spectra.     

Genesis of monazite and Y zoning in garnet from the Black Hills, South Dakota

The paragenesis of monazite in metapelitic rocks from the contact aureole of the Harney Peak Granite, Black Hills, South Dakota, was investigated using zoning patterns of monazite and garnet, electron microprobe dating of monazite, bulk-rock compositions, and major phase mineral equilibria. The area is characterized by low-pressure and high-temperature metamorphism with metamorphic zones ranging from garnet to sillimanite zones. Garnet porphyroblasts containing euhedral Y annuli are observed from the garnet to sillimanite zones. Although major phase mineral equilibria predict resorption of garnet at the staurolite isograd and regrowth at the andalusite isograd, textural and mass balance analyses suggest that the formation of the Y annuli is not related to the resorption-and-regrowth of garnet having formed instead during garnet growth in the garnet zone. Monazite grains in Black Hills pelites were divided into two generations on the basis of zoning patterns of Y and U: monazite 1 with low-Y and -U and monazite 2 with high-Y and -U. Monazite 1 occurs in the garnet zone and persists into the sillimanite zone as cores shielded by monazite 2 which starts to form in the andalusite zone. Pelites containing garnet porphyroblasts with Y annuli and monazite 1 with patchy Th zoning are more calcic than those with garnet with no Y annuli and monazite with concentric Th zoning. Monazite 1 is attributed to breakdown of allanite in the garnet zone, additionally giving rise to the Y annuli observed in garnet. Monazite 2 grows in the andalusite zone, probably at the expense of garnet and monazite 1 in the andalusite and sillimanite zones. The ages of the two different generations of monazite are within the precision of chemical dating of electron microprobe. The electron microprobe ages of all monazites from the Black Hills show a single ca. 1713 Ma population, close to the intrusion age of the Harney Peak Granite (1715 Ma). This study demonstrates that Y zoning in garnet and monazite are critical to the interpretation of monazite petrogenesis and therefore monazite ages.     

断裂密集带在油运聚成藏中的作用——以三肇凹陷和尚2井区块扶杨油层为例

为研究三肇凹陷和尚2井区块扶杨油层油气成藏规律,采用断裂密集带与油气分布叠合的方法,分析断裂密集带在油气成藏分布中的作用.结果表明:三肇凹陷扶杨油层发育35条断裂密集带,尚2井区块扶杨油层发育9条断裂密集带;油主要分布在断裂密集带两侧,少量分布在断裂密集带内部.断裂密集带对油运移的控制作用表现在2方面:(1)断裂密集带边界断裂为油输导断裂;(2)断裂密集带不利于油横穿其侧向运移,但可沿其侧向运移.断裂密集带对油聚集的控制作用表现在2方面:(1)断裂密集带两侧的地垒和断阶构造是油聚集的有利部位;(2)断裂密集带内部的背形构造也是油聚集的有利部位.     

钇易解石族的端员—钛钇易解石的发现

本矿物为新发现的钇易解石族的端员矿物－钛钇易解石，产于江西省龙南县足洞燕山期中粒白云母花岗岩及其风化壳中。矿物属斜方晶系，常呈板状或短柱状，为天然晶质体，浅黄色，粒度为０．０７５ｍｍ，硬度４．７，比重４．７３，二轴正晶，Ｎｇ＝２．２４８，Ｎｍ＝２．２１２，Ｎｐ＝２．１９４，Ｎｇ－Ｎｐ＝０．０５４，２Ｖ＝７０°。空间群为Ｄ＾１６２ｈ－Ｐｍｎｂ，ａ０＝０．７５０ｎｍ，ｂ０＝１．０９２ｎｍ，Ｃ０＝０．５     

P–Y Curves for Piles Under Seismic Lateral Loads

This paper describes an experimentally based procedure for building dynamic P–Y curves for clays from the Campeche sound in the Gulf of Mexico and for Mexico City clays. Cyclic triaxial and resonant column tests were used to derive hyperbolic stiffness–strain and damping–strain functions that depend on soil plasticity and on relative consistency. The dynamic P–Y curves incorporate these functions and also include hysteretical and geometrical damping characteristics of the pile–soil system; they can be used directly in dynamic interaction analyses of structure–pile–soil systems in the time or the frequency domains. Usual practice relies on pseudo static formulations and a simplified alternative to include P–Y curves in this kind of analysis is also proposed, which is essentially the same as the dynamic ones but does not include radiation or hysteretical damping.     

牙鲆NPY的体外表达及体内检测

神经肽Y(Neuropeptide Y,NPY)被普遍认为是一种重要的促食因子,在调节鱼类的摄食行为方面起着至关重要的作用。为进一步研究牙鲆NPY蛋白的生物学功能,作者克隆了牙鲆NPY成熟肽序列(m-NPY)及含有信号肽的全长序列(f-NPY),利用原核表达系统分别进行体外重组表达,筛选出诱导剂IPTG最佳诱导浓度为0.8 mmol/L及最佳诱导时间3 h;此外,根据牙鲆NPY第49-64位氨基酸序列制备了多克隆抗体并通过Western blot验证该多抗能够有效检验重组NPY及牙鲆体内NPY的表达。研究结果为研究重组牙鲆NPY蛋白在牙鲆水产养殖产业中的应用及检测提供了依据。     

新疆喀拉通克铜镍矿田成矿条件、岩浆通道与成矿潜力分析

位于中亚造山带北缘的喀拉通克早二叠世铜镍硫化物矿区是新疆规模最大的铜镍矿山,包含13个岩体,相当部分为隐伏岩体,其中1号、2号、3号、9号矿床为主力矿床,经过30余年持续开发,最大开采深度已达740 m,已面临后备资源不足的危机。已知矿体主要产于辉长岩、苏长岩、辉长苏长岩以及橄榄苏长岩中,甚至角闪辉长岩局部也含矿,未见超镁铁岩产出,具有显著的磁性(200 nT)、重力(0.29×10~(-5)m/s~2)、激化率异常,以镁铁岩含矿、岩体规模小且成群成带、分异演化程度高、富铜(Cu/Ni约3:2)、PGE较高、块状硫化物贯入矿体普遍发育为特色。其围岩为含炭质板岩、片岩和凝灰岩,变形强烈,常规电法受到炭质层的干扰。依据岩石学、地球化学研究,岩浆源于软流圈地幔,基于与东天山同期铜镍矿床含矿岩相及其比例和剩余重力异常的比较,推断其应发育有相当比例的超镁铁岩,因而深部出现超基性岩的可能性很高,且含矿性应更好。这一推断得到坑道钻探的证实,2013年矿区在Y2岩体东段650~740 m深度和Y2岩体西段400~500 m深度发现隐伏超镁铁岩且含矿,局部见贯入块状矿体。橄榄辉石岩、辉石橄榄岩系矿区首次发现,粒度很细,发育强烈的蛇纹石化、纤闪石化,推测只是隐伏超基性岩的头部。结合控岩控矿构造的追溯及南、北岩带的侧伏和倾伏方向判断,硫化物珠滴构造的发现与系统观测统计,围岩烘烤边和角岩化的研究分析,提出南岩带主岩浆通道位于Y2与Y3岩体之间,而不是原普遍认为的岩浆通道位于Y1与Y2岩体之间。结合矿区的现状,提出采用高分辨率浅层地震、CSAMT和瞬变电磁地-井测量,结合传统的高精度重力勘探、磁法勘探和激发极化法来勘探和预测南岩带深部隐伏含矿超镁铁岩的空间位置和产状,圈定岩浆通道和隐伏铜镍矿体,进而推动北岩带和外围G21、22号岩体的深部探矿工作。     

P–T–t evidence for mechanisms of vertical tectonic motion in a contractional orogen: north-western US and Canadian Cordillera

The >1800 km long Coast Mountains–North Cascades orogen of the Canadian Cordillera and north-western US developed as a continental magmatic arc. Metamorphic rocks in the orogen contain widespread evidence for burial of supracrustal rocks to depths of c. 40 km, followed by nearly isothermal decompression to depths of <10 km. Near many shallowly-emplaced, mid-Cretaceous plutons, low-pressure contact metamorphic effects were overprinted by high-pressure regional metamorphic minerals and textures, as evidenced by kyanite±staurolite pseudomorphs after andalusite in metapelitic rocks. Therefore, near-pluton rocks record the loading history of the orogen. Metapelitic rocks not associated with plutons only preserve evidence for high-pressure conditions and/or high-temperature decompression, as indicated, for example, by sillimanite and cordierite after kyanite and garnet, respectively. Petrological evidence for burial and decompression is therefore recorded in different rocks. Various regions of the orogen differ in timing of metamorphism, the overall shape of P–T paths and the relative timing and regional extent of the high-pressure event, but most of these data and observations are consistent with thrusting and/or pure shear thickening as primary loading mechanisms throughout the orogen, as opposed to magma-dominated loading. This interpretation is further supported by comparison with thermal models, which demonstrate that the P–T paths are consistent with simultaneous thrusting and folding at a high initial geothermal gradient (35–40 °C km^?1) in much of the orogen. A high geothermal gradient supports tectonic models invoking intra-arc contraction and suggests that magmatism played an important role in regional temperature-time paths. This tectonic-thermal history may be typical of other contractional orogens and illustrates the importance of large vertical displacement of crust in magmatic arcs.     

Tectono-magmatic evolution from accretion to collision in the southern margin of the Central Asian Orogenic BeltSCIEI北大核心CSCD

造山带演化及增生到碰撞的转变是板块构造与大陆动力学研究中的前沿科学问题。中亚造山带被认为是古亚洲洋长期俯冲-增生演化形成的显生宙最大的增生造山带,以发育巨量的面状展布的俯冲-增生相关的弧岩浆岩为特征。并且,由于中亚增生型造山带在潘吉亚最后聚合过程中发生弧弧(陆)碰撞,因此缺乏大规模且跨构造单元的碰撞相关的构造和变质等物质标志。显然,能否识别出大洋闭合期间碰撞作用的岩浆标志成为确定增生造山带增生过程终止的关键之一。本文系统研究确定:中亚造山带东南缘二叠纪到三叠纪钙碱性-碱钙性岩浆在空间分布上显示出由北西向南东迁移演化的特征;在岩浆性质上具有从二叠纪新生地壳来源的弧岩浆向早-中三叠世碰撞挤压背景下古老陆壳组分逐渐增多的高Sr/Y岩浆以及晚三叠世后造山伸展相关的A型花岗岩演化的特征。这些特征提供了俯冲-增生向碰撞造山演变的关键岩浆岩证据。结合区域资料,厘定出增生造山带最后碰撞相关的标志性岩浆为沿缝合带呈零星线性展布的增厚下地壳源区的高Sr/Y花岗岩类,构建了中亚造山带南缘从双向俯冲-增生到增生楔-增生楔碰撞及后造山伸展的三阶段构造-岩浆演化模型。系统对比研究,揭示出增生-碰撞相关的岩浆记录沿横向展布在中亚造山带南缘甘肃北山到吉林中部一带,表明碰撞挤压相关的岩浆作用在中亚造山带南缘具有一定的普适性。中亚造山带南缘从增生到碰撞的岩浆演化记录的厘定,证实显生宙最大的巨型增生造山带演化末期经历了碰撞造山作用,对进一步深入探索增生造山演化末期碰撞相关的标志性岩浆具有重要意义。     

藏南冈底斯岩基东段中新世中酸性高Sr/Y比岩浆岩的地球化学特征及成因探讨

藏南冈底斯带广泛发育中新世中酸性高Sr/Y比岩浆岩,对该类型岩石的成因研究可为藏南后碰撞岩浆活动提供良好的记录和约束。通过对冈底斯带东段中酸性岩浆岩进行锆石U-Pb年代学研究表明,该中酸性岩浆岩形成于16～18Ma,为中新世时期;全岩地球化学数据表明岩浆岩具有高SiO_2含量( 64%),高钾富钠,高Sr、低Y和高Sr/Y比,轻稀土富集、重稀土亏损且较平坦的特征,显示出埃达克质岩的地球化学亲缘性;与冈底斯带中段～14Ma埃达克质闪长玢岩脉相比,冈底斯带东段的中新世岩浆岩具有更高的K含量;锆石Hf同位素分析结果表明,中新世中酸性岩浆岩具有正的且变化较大的εHf(t)值(+1. 2～+14. 4);全岩(La/Yb)N值对中新世地壳厚度的估算结果为77～84km,处于壳幔边界处。综合上述数据分析表明,冈底斯带东段中新世中酸性高Sr/Y岩浆岩的成因为拉萨地块加厚下地壳(占主体的新生下地壳+少量古老地壳)的部分熔融,并在源区残留了石榴子石和角闪石,造成熔融的热量来源可能为拉萨地体岩石圈根部拆沉导致的热扰动。