|Alternative Title||The application of fractal and crystal size distribution in quantitative texture analysis in petrology and its implications|
|Thesis Advisor||周文戈 ; 朱茂旭|
|Place of Conferral||中国科学院地球化学研究所|
|Keyword||岩石结构 定量分析 分形 晶体粒度分布 榴辉岩|
近30年来岩石结构的研究仍然以描述性为主，严重滞后于岩石学的其它分支。本论文以分形（Fractal）理论及晶体粒度分布（Crystal Size Distribution，CSD）理论为基础，结合高温高压实验手段，定量化分析了不同温度、压力和时间条件下各种矿物相（角闪石、单斜辉石和石榴子石）的形态及粒度分布特征。其中，一方面矿物相集合体的形态采用分形分析手段，通过双相盒计数法及三相盒计数法对粗面玄武岩（10084）实验产物两相（角闪石+残余熔体）和斜长角闪岩（JN116）实验产物三相（单斜辉石+石榴子石+残余熔体）系统进行了详细的定量化处理，判断了两相和三相系统中最可能的分形相，并计算了相应的分数维。另一方面，采用晶体粒度分布方法系统分析了斜长角闪岩实验产物中单斜辉石和石榴子石两种矿物相的晶体粒度分布特征，通过对晶体粒度分布曲线的线性段进行拟合，获得了相应的CSD参数，从而对晶体生长动力学参数诸如成核密度、成核速率、生长速率等参数进行了限定。论文主要取得了以下成果及认识：1. 建立了一套完整的岩石结构参数的定量化流程及方法，掌握了如何从二维岩石剖面中分离各种矿物相并对单一相进行定量化结构参数的测量。2. 在压力0.6~2.6 GPa，温度860~970℃条件下，含水粗面玄武岩熔体冷却结晶形成的角闪石矿物集合体和残余熔体具有自相似特征，采用双相盒计数法确定了残余熔体相为分形而角闪石相为欧几里得（除0.6 GPa，970℃实验存在异常）。获得的残余熔体分数维变化范围1.782~1.848。并且在相同的温度下，压力是影响分形演化的主要因素，残余熔体的分数维DB与压力P表现为线性负相关，DB-P的关系有可能成为潜在的地质压力计。3. 在时间0.25~400 h，温度900~1100℃，压力1.5~3.0 GPa范围内，以斜长角闪岩（JN116）粉末进行了不同恒温时间、不同温度及不同压力三个序列的部分熔融实验，获得的实验产物主要由单斜辉石、石榴子石和残余熔体组成。采用CSD分析方法获得了不同时间、温度和压力下的CSD曲线及CSD参数。整体上单斜辉石的CSD线性趋势比石榴子石的线性趋势要好。CSD参数均表现了与时间、温度和压力的相关性，并且时间对CSD的影响在三者中是最大的。通过CSD参数获得了单斜辉石和石榴子石生长速率与时间、温度、压力的关系式。此外，依据实验获得的石榴子石的生长速率与时间数据，结合前人获得的天然变质岩中石榴子石的生长速率和时间，拟合得到了石榴子石生长速率与生长时间的关系。4. 将两相分形判断扩展到了三相系统中，理论上判断了三相系统中最可能的分形情况。以斜长角闪岩实验产物为三相研究对象，利用联合拟合方法判断了单斜辉石+石榴子石+残余熔体组成的三相系统中单斜辉石相为欧几里得，石榴子石和残余熔体相为分形。获得的石榴子石集合体的分数维变化范围为1.430~1.820，残余熔体的分数维变化范围为1.688~1.851。5. 对大别山新店榴辉岩XD9601的石榴子石进行了CSD处理及分形处理。通过CSD获得的石榴子石的特征粒度变化范围为0.213~0.278 mm。结合本论文获得的石榴子石生长速率和时间的关系式，估算了高压变质作用中石榴子石的生长速率的上限和下限，获得了新店榴辉岩中石榴子石生长时间较为合理的上限下限为117-231 Ma和0.55-0.72 Ma。通过分形分析，认为大别新店榴辉岩中石榴子石集合体具有分形特征，与实验产物中石榴子石集合体具有分形特征的结果一致，并计算了相应的分数维，获得的石榴子石集合体分数维变化范围为1.638~1.748之间，也在实验产物石榴子石集合体分数维变化范围之内。6. 初步探讨了两种特殊变形对岩石中矿物CSD的影响。在体积变化，矿物形态不变的均匀变形条件下，变形仅影响矿物CSD的截距，而不影响其斜率。在岩石体积不变，矿物形态发生改变的单轴压缩均匀变形条件下，当压缩率小于10%时，变形对CSD的截距和斜率影响很小；当压缩率大于10%时，变形对矿物CSD的截距和斜率都有明显影响，且对CSD的斜率影响更显著。此外，在大压缩率条件下，变形对矿物CSD的影响显示出各向异性。
The study of rock structure has been mainly descriptive in the past 30 years and lagged far behind other branches of petrology. Based on the theories of Fractal and Crystal Size Distribution (CSD), combining with High Temperature and High Pressure experiments, the shape and size distribution of amphibole, clinopyroxene and garnet from experimental products under different temperature, pressure and time have been quantified. On the one hand, the shape of mineral aggregation was quantified by bi-phase box counting for the experimental products (amphibole+residual melt) of trachybasalt (10084) and tri-phase box counting for the experimental products (clinopyroxene+garnet+residual melt) of amphibolite (JN116). The most probable fractal phase in the bi-phase and tri-phase system is determined and the corresponding fractal dimension is calculated. On the other hand, CSD characteristics of clinopyroxene and garnet in the experimental products of amphibolite was analyzed systematically. By fitting the linear section of each CSD curve, the CSD parameters was obtained. Finally, the kinetic parameters (e.g. nucleation density, nucleation rate, growth rate) of crystal growth could be limited. The main achievements and insights are as follows.1. Established a complete set of process and method of quantifying the parameters of the rock structure, mastered how to isolated single mineral phase from two-dimensional rock sections with various mineral phases and got the measurement of quantitative structure parameters of each single-phase.2. Microstructure of amphibole aggregation growth from the trachybasalt melt and redidual melt at 0.6~2.6 GPa and 860~970℃ shows self-similarity. By using the bi-phase box counting method, the residual melt is identified as the fractal and amphibole as the Euclidean except for the experiment at 0.6 GPa and 970℃. The fractal dimension of the residual melt within the range of 1.782~1.848 has been acquired. Pressure is the dominant factor for the fractal evolution at the same crystallization temperature. A linear relationship between the DB value and pressure was obtained and if this relationship can be verified in the future, the DB?P relationship can be used as a potential geological barometer.3. Under the condition of time within 0.25~400 h, temperature within 900~1100℃, pressure within 1.5~3.0 GPa, three sequences (different time, temperature or pressure sequence) experiments of partial melting was conduct on amphibolite (JN116). The experimental products are mainly composed of clinopyroxene, garnet and residual melt. The CSD curves and parameters of each experiment was acquired by CSD analysis. Generally, the linear trend of CSD for clinopyroxene is better than that for garnet. The CSD curves shows the correlation between time, temperature and pressure, and the effect of time on CSD is the largest among the three. The relationship between the growth rate and time, temperature and pressure were obtained by CSD parameters. In addition, Fitting the data obtained on the basis of experiments, combined with previous natural metamorphic rock in the garnet growth rate and time, the relationship between growth rate and growth time of garnet was obtained.4. The bi-phase fractal judgment is extended to the tri-phase system, which theoretically determines the most probable fractal phase(s) of the tri-phase system. Using the experimental products of amphibolite as the objects of research, combined with conjoint fitting method to determine the Euclidian phase is clinopyroxene and the fractal phases are garnet and residual melt in the tri-phase system of clinopyroxene + garnet + residual melt. The fractal dimension of garnet aggregation is in the range of 1.430~1.820, and the fractal dimension of residual melt is in the range of 1.688~1.851.5. CSD and fractal treatments were carried out on the garnet of eclogite (XD961) from Xindian in Dabie. The characteristics size of garnet by CSD is in the range of 0.213~0.278 mm. Based on the relationship between the growth rate and time of garnet obtained in this paper, the upper and lower limit of the growth rate of garnet in high pressure metamorphism were estimated. The upper and lower limit of the growth time of garnet in eclogite from Xindian is 117-231 Ma and 0.55-0.72 Ma. By fractal analysis, the garnet aggregation in the eclogite has the characteristics of fractal, which is consistent with that in the experimental products. The fractal dimension of garnet aggregation was obtained and vary from 1.638 to 1.748 which is also in the range of fractal dimension for garnet aggregation acquired from experiments.6. The changes of mineral CSD in rocks with transformation are preliminary discussed in this paper. In the case of changing the volume of rock but the mineral morphology does not change, deformation only affects the intercept of the mineral CSD without affecting its slope. In another case of changing the mineral morphology but the volume of rock does not change, When the compression ratio is less than 10%, the effect of deformation on the intercept and slope of CSD is very small; when the compression ratio is greater than 10%, the deformation has a significant effect on the intercept and slope of the mineral CSD and has a more significant effect on the slope of CSD. In addition, under the condition of high compression rate, the effect of deformation on the mineral CSD shows anisotropy.
|胡贤旭. 分形与晶体粒度分布在岩石结构定量化分析中的应用及其意义[D]. 中国科学院地球化学研究所. 中国科学院大学,2018.|
|Files in This Item:|
|分形与晶体粒度分布在岩石结构定量化分析中（8031KB）||学位论文||开放获取||CC BY-NC-SA||View Application Full Text|
|Recommend this item|
|Export to Endnote|
|Similar articles in Google Scholar|
|Similar articles in Baidu academic|
|Similar articles in Bing Scholar|
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.