Nomenclature in any science is of fundamental importance. From performance comparison of isometric and modified or hybrid log-ratio transformations of major elements, we present a complete multidimensional classification scheme for altered igneous rocks for High-Mg rock varieties and magma and rock types. This scheme is efficiently applicable through a computer package called Multidimensional Igneous rock Classification System (MICSys) that encapsulates four new online computer modules (HMgClaMSys_ilr, MagClaMSys_mlr, and IgRoClaMSys_mlr and a robustness evaluation module). We used a major element database of multinormally distributed 33868 samples of relatively fresh igneous rocks and compared the performance of isometric log-ratio and modified log-ratio transformations, both of which were multinormally distributed in terms of the 9 log-transformed variables as confirmed by the DOMUDaF program. The system must be trained from only fresh rocks because the prior class assignment requires an efficient scheme accepted by all, which is available only for fresh rocks. The multivariate technique of linear discriminant analysis (LDA) and canonical analysis applied to the two transformations provided the same percent success or correct classification for the respective databases. With these findings, we reinforce the recently published work on the International Union of Geological Sciences (IUGS)-consistent multidimensional classification of altered igneous rocks. The numerous tests and applications documented earlier on multidimensional classification were applied in the present work. The mathematical properties of log-ratio transformations are no longer important, provided the multidimensional technique involves the LDA and canonical analysis. MICSys available for online application at the web portal http://tlaloc.ier.unam.mx, was successfully applied to 6 new tests and 11 new applications to illustrate the usefulness of our multidimensional classification system to igneous rocks altered from post-emplacement compositional changes. Robustness of the new scheme for altered igneous rock nomenclature as compared to the conventional IUGS procedure for fresh rock nomenclature was confirmed from simulation of post-emplacement alteration of all elements in 28 different rock compositions representative of all rock types. Even greater robustness was demonstrated against analytical uncertainty propagation in 14 geochemical reference materials issued from Canada (3), France (3), Japan (5), and the USA (3). The estimation of robustness against post-emplacement changes and uncertainty propagation was facilitated by the incorporation of a fourth module in MICSys. This work, therefore, clearly shows that, for altered rocks, the new multidimensional scheme should be used, instead of the conventional classification meant for fresh rocks only.

任何科学中的术语都是至关重要的。从主要元素的等轴测图和修正图或混合对数比变换的性能比较，我们为高镁岩石种类，岩浆和岩石类型提出了火成岩蚀变岩石的完整多维分类方案。该方案可通过称为多维火成岩分类系统（MICSys）的计算机程序包有效地应用，该程序包封装了四个新的在线计算机模块（HMgClaMSys_ilr，MagClaMSys_mlr和IgRoClaMSys_mlr和耐用性评估模块）。我们使用了一个主要元素数据库，该数据库包含相对较新的火成岩的多态分布的33868个样本，并比较了等距对数比和改进的对数比转换的性能，根据DOMUDaF程序的确认，这两个变量均按照9个对数转换变量呈多正态分布。该系统必须仅从新鲜的岩石进行培训，因为先前的课程分配要求所有人都接受有效的方案，该方案仅适用于新鲜的岩石。应用于两个转换的线性判别分析（LDA）和规范分析的多元技术为各个数据库提供了相同的成功百分比或正确的分类。有了这些发现，我们加强了国际地质科学联合会（IUGS）最近发表的有关变质火成岩多维分类的工作。先前在多维分类中记录的大量测试和应用已应用于当前工作中。如果多维技术涉及LDA和规范分析，则对数比转换的数学属性不再重要。可从Web门户网站http://tlaloc.ier.unam.mx上在线应用的MICSys已成功应用于6个新测试和11个新应用，以说明我们的多维分类系统对从位移后成分改变后的火成岩的有用性变化。通过模拟代表所有岩石类型的28种不同岩石成分中所有元素的置入后变化模拟，证实了与新的IUGS方法相比，新的火成岩命名法新方法的鲁棒性。从加拿大（3），法国（3），日本（5）和美国（3）发行的14种地球化学参考材料中，证明了更高的鲁棒性，可防止分析不确定性的传播。通过在MICSys中并入第四个模块，可以简化对置入后变化和不确定性传播的鲁棒性评估。因此，这项工作清楚地表明，对于蚀变的岩石，应使用新的多维方案，而不是仅用于新鲜岩石的常规分类。