排序方式： 共有8条查询结果，搜索用时 218 毫秒
1
1.
浓度是溶液中客观存在的物理性质,活度则指非理想溶液(包括非理想固溶体)中组分的"有效浓度"。本文以石榴子石-黑云母(GB)温度计、石榴子石-Al2SiO5矿物-斜长石-石英(GASP)压力计为例,探讨了矿物活度模型对于温度计与压力计的影响。将石榴子石和黑云母作为理想或非理想固溶体,根据实验数据建立的不同版本的石榴子石-黑云母温度计,都能较好地重现实验温度,还能识别递增变质带、倒转变质带、热接触变质晕中,不同地带变质温度的系统性变化。但是,将石榴子石和黑云母同时作为理想固溶体的温度计,系统误差明显较大,计算温度系统性偏低。同时采用石榴子石和黑云母非理想活度模型,得到的温度计精确度高。将石榴子石和斜长石都作为理想固溶体建立的GASP压力计,计算压力明显偏高,不能准确识别Al2SiO5矿物的稳定域,有明显的系统误差。如果同时采用石榴子石与斜长石的非理想活度模型,即便不同活度模型之间热力学参数有很大差别,得到的GASP压力计准确度都较高,还能准确识别Al2SiO5矿物的稳定域。迄今为止,还严重缺乏适用于多种岩石类型和宽广温度-压力范围的通用型矿物活度模型。此外,虽然矿物温度计、压力计不涉及流体、熔体,但是其计算结果的确能准确反映客观地质事实,并不受流体、熔体的影响。 相似文献
2.
地幔岩矿物压力计评述 总被引：6，自引：4，他引：2
适用于地幔岩石的矿物压力计有石榴石-斜方辉石压力计、石榴石-单斜辉石压力计、橄榄石-单斜辉石压力计、铬尖晶石压力计、二辉石压力计等有限几类.本文通过将这些压力计应用于岩石学相平衡实验数据,检验了其精确度.再将它们应用到天然地幔岩石样品,包括石榴石相二辉橄榄岩、尖晶石相二辉橄榄岩、石榴石-尖晶石过渡相二辉橄榄岩、含金刚石和石墨的地幔岩石,检验了其准确度.初步结论是,现有的石榴石-斜方辉石压力计(Nickel and Green,1985;Taylor,1998;Brey et al．,2008)质量相对最优,石榴石-单斜辉石压力计(Nimis and Taylor,2000;Simakov and Taylor,2000)次之.在应用这些压力计时,可配合二辉石温度计(Brey et al．,1990;Taylor,1998)或石榴石-橄榄石温度计(Wu and Zhao,2007),来同时估算平衡压力和温度.其余的压力计精确度和准确度都还很不够,需要更精确深入的实验研究来标定质量优良的压力计. 相似文献
3.
In this contribution we have empirically calibrated the garnet–biotite–muscovite–aluminosilicate–quartz (GBMAQ) barometer using low- to medium–high-pressure, mid-grade metapelites. Application of the barometer suggests that the GBMAQ and GASP barometers show quite similar pressure estimates. Furthermore, metapelites within thermal contact aureole or very limited geographic area show no meaningful pressure diversity determined by the GBMAQ and GASP barometers which is the geological reality. The random error of the GBMAQ barometer is expected to be around ± 0.8 kbar, and this barometer shows no systematic bias with respect to either pressure, or temperature, or AlVI in muscovite, or Fe in biotite, or Fe in garnet. The GBMAQ barometer is thermodynamically consistent with the garnet–biotite geothermometer because they share the same activity models of both garnet and biotite. This barometer is especially useful for assemblages with Ca-poor garnet or Ca-poor plagioclase or plagioclase-absent metapelites. Application of this barometer beyond the calibration ranges, i.e., P–T range and chemical ranges of the minerals, is not encouraged. 相似文献
4.
Geochemical genesis of geothermal waters from the Longling hydrothermal area,Yunnan, Southwestern China 
下载免费PDF全文
下载免费PDF全文 GUO Qing-hai ZHANG Xiao-bo LIU Ming-liang LI Jie-xiang ZHOU Chao ZHANG Can-hai ZHU Ming-cheng GUO Wei WANG Yan-xin 《地下水科学与工程》2015,3(3):213-221
Longling is characterized by a wide distribution of hydrothermal areas, among which the Banglazhang hydrothermal system is the most geothermally active. Banglazhang is marked by intensive hydrothermal activities including hot springs, geysers, fumaroles and hydrothermal explosions. The geothermal waters from the Longling region are mainly HCO_3-Na type with low but comparable SO_4 and Cl concentrations. Calculations based on a variety of chemical geothermometers and a K-Ca geobarometer indicate that the Banglazhang hydrothermal system has much higher subsurface temperature and CO_2 pressure compared to the other systems such as Daheba, Dazhulin and Huangcaoba. However, geothermal water samples collected from all these alternative hydrothermal areas are either partially equilibrated with reservoir minerals or are immature. The silica-enthalpy relationships of Banglazhang geothermal waters indicate the presence of a deep geothermal fluid with an enthalpy value and silica concentration of 945 J/g(up to around 220 °C) and 339 mg/L. Our work indicates the Banglazhang area is a promising source in terms of long-term utilization of hydrothermal resources. 相似文献
5.
宁镇山脉中段矽卡岩型铁铜矿床的成矿深度是该地区深部找矿前景分析的重要参考因素,以往多运用地质分析法来定性讨论。通过野外调查,发现这些矿床常有少量闪锌矿伴生。初步研究了该地区伏牛山铜矿、安基山铜矿、团山硫铁矿、盘龙岗铁铜矿以及胄王村多金属矿等代表性矿床（点）所伴生闪锌矿的产出特征、矿物共生组合、常量化学成分及晶体结构,发现该区闪锌矿形成于热液硫化物阶段的中晚期,部分矿区具有至少两个结晶世代,无论其共生矿物、结晶形态、颜色、成分或晶体结构均随产状和矿物共生组合有规律地变化。只有团山硫铁矿和伏牛山铜矿的第一世代闪锌矿与六方磁黄铁矿及黄铁矿平衡共存,符合闪锌矿地质压力计应用条件,用前人修正的闪锌矿压力计获得的成矿压力与地质分析结论吻合,为0．9kPa～1．2kPa,相当于成矿深度2420m～3630m,比照处在相同成矿带的湖北大冶和安徽铜陵深部找矿结果,认为该区仍有深部找矿前景。 相似文献
6.
The historic development of the first geobarometer for spinel lherzolite based on the distribution of calcium between existing olivine and clinopyroxene is reported here.
Kohler and Brey(1990) suggested the geobarometer as follows:
P(108Pa)=(−TlnDCa−11982+361T)/56.2 for T≥ (1275.25+2.827P) (K),
P(108Pa)=( −TlnDCa−5792−1.25T)/42.5 for T≤(1275.25+2.827P) (K).
Based on their calibrated experiments for calcium exchange between olivine and clinopyroxene from wide temperature-pressure range. 相似文献
Kohler and Brey(1990) suggested the geobarometer as follows:
P(108Pa)=(−TlnDCa−11982+361T)/56.2 for T≥ (1275.25+2.827P) (K),
P(108Pa)=( −TlnDCa−5792−1.25T)/42.5 for T≤(1275.25+2.827P) (K).
Based on their calibrated experiments for calcium exchange between olivine and clinopyroxene from wide temperature-pressure range. 相似文献
7.
正确测定尖晶石相橄榄岩的Ｔ－Ｐ关系，对于了解岩石圈地幔的许多基本性质和过程具有重要意义。介绍了根据Ｃａ在共存的橄榄石和辉石之间的分配而建立的适用于尖晶石相橄榄岩的第一个定量地质压力计，叙述了该地质压力计的研究历史、现状和使用中的注意事项。 相似文献
8.
甘肃敦煌观音沟地区变质作用初步研究 总被引：9，自引：7，他引：2
敦煌东南三危山观音沟地区,出露有石榴斜长角闪片麻岩,岩石中保存了三个阶段的变质矿物组合。进变质阶段的矿物组合(M1)以石榴子石变斑晶中的包裹体矿物组合(Hbl1+Pl1+Qtz1)为代表,形成条件约为550~575℃/5.2~5.7kbar(绿帘角闪岩相)。变质高峰期矿物组合(M2)主要由石榴子石变斑晶和基质矿物(Hbl2+Pl2+Qtz2±Cpx2)组成,形成温度670℃,压力11.9kbar(角闪岩相)。退变质阶段矿物组合(M3)为后成合晶矿物组合(Hbl3+Pl3+Qtz3),形成条件约为590~640℃/4.3~5.9kbar(角闪岩相)。观音沟石榴斜长角闪片麻岩记录了包含进变质、变质高峰、退变质过程的造山过程"西阿尔卑斯"型P-T轨迹,其中退变质阶段具有明显的近等温降压特征。变质作用P-T轨迹指示本地区可能经历了俯冲-碰撞-快速抬升的造山过程。结合年代学资料,该期造山事件可能发生于泥盆纪。 相似文献
1