Variations of Sr–Nd–Hf isotopic systematics in basalt during intensive weathering

The Sr–Nd–Hf isotopic compositions of both saprolites and parent rocks of a profile of intensively weathered Neogene basalt in Hainan, South China are reported in this paper to investigate changes of isotopic systematics with high masses. The results indicate that all these isotopic systematics show significant changes in saprolites compared to those in corresponding parent rocks. The ⁸⁷Sr/⁸⁶Sr system was more seriously affected by weathering processes than other isotope systems, with ε_Sr drifts 30 to 70 away from those of the parent rocks. In the upper profile (> 2.2 m), the Sr isotopes of the saprolites show an upward increasing trend with ε_Sr changing from ~ 50 at 2.2 m to ~ 70 at 0.5 m, accompanying a upward increasing of Sr concentrations, from ~ 10 μg/g to ~ 25 μg/g. As nearly all the Sr of the parent rock has been removed during intensive weathering in this profile, the upward increasing of Sr concentrations in the upper profile suggests import of extraneous Sr. Rainwater in this region, which enriches in Sr (up to 139 μg/L) from seawater, may be the important extraneous source. Thus, the Sr isotopes of the saprolites in the upper profile may be mainly influenced by import of extraneous materials, and the Sr isotopic characteristics may not be retained. In contrast, the ε_Nd and ε_Hf of the saprolites drift only 0–2.6 and 0–3.7 away from the parent rocks, respectively. The negative drifts of the ε_Nd and ε_Hf are coupled with Nd and Hf losses in the saprolites; i.e., larger proportions of Nd and Hf loss correspond to lower ε_Nd and ε_Hf. Compared with the relative high Nd and Hf concentrations of the saprolites, the contributions of extraneous Nd and Hf both from wet and dry deposits of aeolian input are negligible. Thus, the ε_Nd and ε_Hf changes in the profile are mainly resulted from consecutive removal of the Nd and Hf. Calculation indicates that the ¹⁴³Nd/¹⁴⁴Nd and ¹⁷⁶Hf/¹⁷⁷Hf ratios in saprolites are all significantly lower than their initial values in the parent rock. Simply removing part of the Nd and Hf by incongruent decomposing some of the minerals may not account for this. Fractionation should be happen, which ¹⁴³Nd and ¹⁷⁶Hf may be preferentially removed from the profile relative to ¹⁴⁴Nd and ¹⁷⁷Hf during intensive chemical weathering, resulting in lower ¹⁴³Nd/¹⁴⁴Nd and ¹⁷⁶Hf/¹⁷⁷Hf ratios in saprolites relative to the parent rock, even though details for this process is not known. A positive correlation is observed between the ε_Nd and ε_Hf of the saprolites. Interestingly, the saprolites with a net loss of Nd and Hf in the upper profile show good positive correlation, and the regression line parallels the terrestrial array. By contrast, saprolites with a net gain of Nd and Hf in the lower profile generally show higher ε_Hf values at a given ε_Nd value, and the regression line between these ε_Nd and ε_Hf appears to parallel the seawater array. This supports the hypothesis that the contribution of continental Hf from chemical weathering release is the key to the obliquity of the seawater array away from the terrestrial array of the global ε_Nd and ε_Hf correlation. Our results also indicate that caution is needed when using ε_Sr, ε_Nd, and ε_Hf to trace provenances for sediments and soils.     

胶南隆起北缘石门-薛家庄韧性剪切带

石门－薛家庄韧性剪切带曾经历过正－左行平移、正－右行平移及左行正滑三期剪切运动。其东段以正－右行平移运动为主，中段具左行正滑性质，而其西段（小卜落崮韧性剪切带）则主要为左行平移。该剪切带同时又是一条经受了低绿片岩相－角闪岩相变形的多相剪切变形带。在剪切带的横剖面上，石英与斜长石的粒度在弱变形带中具双峰式分布的特征，在强变形带中则细而均匀；钾长石的粒度在弱变形带中粗而均匀，在强变形带中则呈现双峰式分布。钾长石和斜长石在韧性变形过程中均可向钠长石转化，应力越大转化越彻底。剪切带的变形机制为简单剪切机制，石英滑移系既有底面滑移又有柱面、菱面滑移。     

胶南造山带及邻近地区的重磁场特征及地质解释

胶南造山带的重磁场特征为一条醒目的重力低、磁力高值带，走向北东－南西，陆上部分长约450km，宽40～70km。其重磁场值一般为0×10－5m／S2～20×10－5m／S2、0～300nT，反映胶南造山带的轮廓及带内低密度的早元古代晋宁期花岗岩基和中强磁性的中生代燕山晚期岩浆岩的分布。根据重力场降低、磁异常升高程度和规模大小（宽窄），该重磁场带又可分为日照－青岛、乳山－威海、即墨－海阳三段，前者重力低、磁力高的程度较强，范围较大。造山带内重磁异常值具负相关关系，域值呈正相关性，即重力值越低的地区磁异常值越高，二者的范围大体相当。这一特征反映了造山带内部早元古代晋宁期花岗片麻岩的发育程度和中生代岩浆岩侵入的规模。胶南造山带的重力低、磁力高值带与连云港－苏山岛重力高、磁力低值带恰成对照。后者重磁场值一般为10×10－5m／S2～30×10-5m／S2、一50～-100nT，反映连云港－苏山岛块体的结晶基底由高密度、低磁性的原东海群、荆山群包体和无古宙侵入岩组成。该造山带南东侧西低东高的重力梯度带（Vzz＝1．2×10－5m·S－2／km～1．75×10－5m·S－2／km）反映了赣榆一荣成断裂（倾向NW）的存在；北西侧正磁异常带表明该断裂为控岩断裂，其南段的正负重力梯度带（Vzz＝1．0×10-5m·S-     

A Discussion of Concavo-Convex Contacts between Oolites and Quartz Grains in Mixed Siliciclastic-Carbonate Rocks in Huanghua Basin, China

Concavo-convex contacrs between oolites and quartz grains are observed in mixed siliciclastic-carbonate rocks of the lower part of number 1 of Shahejie Formation, beach area, Dagang. Thin sections observation shows that oolite is convex in quartz grain, and oolite is complete. A possible explanation for it is pressure dissolution under alkaline fluid.     

Diagenetic Sequences Analysis of Fuyu Reservoir in Qijia - Gulong Depression, Northern Songliao Basin

Five paragenetic associations are recognized in Fuyu reservoir of Qijia - gulong depression of Daqing oil field: 1 )detrital illite permeation, glauconite and pyrite precipitation; 2 ) feldspar dissolution, kaolinite precipitation and the incipient quartz overgrowths; 3 ) early calcite cements; 4 ) postdate quartz overgrowths and pore - filling quartz, authigenetic illite and chlorite formation, feldspar overgrowths, petroleum injections, K - feldspar and calcite cement dissolution; 5) pore - filling calcite and calcite replacement.     

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钻孔应变仪体应力灵敏系数的影响因素研究

分别计算了水泥弹性模量、水泥层厚度、钢筒厚度、岩石弹性模量等对钻孔应变仪体应力灵敏系数的影响,得出:1)在水泥弹性模量小于某个固定值时,体应力灵敏系数随水泥弹性模量的增大而增大,大于这个值时,体应力灵敏系数又随水泥的弹性模量增大而变小;2)当水泥层厚度比N<2时,体应力灵敏系数变化剧烈,受水泥层厚度影响较大;3)体应力灵敏系数随钢筒厚度及岩石弹性模量的增大而变小。     

地分割证在房地产交易中的应用

当前，各地房地产市场活跃，房地产交易日益频繁，房地产价格一路攀升，在房地产交易中，当你用攒了半辈子的钱买了一套新房却长期拿不到土地使用证的时候，当你想进行房地产交易却因“两证”不全暗自焦急的时候，当你为办理各种房产证明不得不四处奔波的时候，就会想有没有一种措施能做到便民、省心呢？     

Estimation on Aesthetic Value of Tourist Landscapes in a Natural Heritage Site： Kanas National Nature Reserve, Xinjiang, China

Most world natural heritage sites are designated partly by reason of their prominent aesthetic values in accordance with Article Ⅶ of World Natural Heritage Convention.In this paper, the aesthetic values of Kanas National Nature Reserve, which has potential for such designation, was analyzed quantitatively using scenic beauty estimation(SBE).The landscapes of 19 representative scenic spots in the Kanas National Nature Reserve in summer and autumn were selected as the objects of evaluation.The contributions of different landscape factors to the aesthetic value of the Kanas National Nature Reserve were revealed using a multivariate quantitative model.The main factors affecting the aesthetic value were waterscapes, vegetation, mountains, folk culture and the tourist environment.The t-test and F-test results are extremely significant.According to the results, some suggestions were given for conserving the landscapes in the Kanas National Nature Reserve.