Tibet Rock-Dianying Volcanic Rock

When we discovered Washan rock, we assumed that there was a boron-rich Washan magma in nature. In addition, it is predicted that there should be rapid crystallization of Washan magma under hypabyssal-ultrahypabyssal conditions, formation of Washan porphyry, volcanic rocks generated under surface conditions (temporarily called Washan rhyolite) and fully crystallized Washan pegmatite under good sealing conditions. (13) Makushani rock. These geochemical properties of boron and its influence on granite slurry are equivalent to those of fluorine. According to the experimental data of diagenesis and mineralization of fluorine-rich granite slurry system, fluorine also affects the mineral crystallization order of acid magma and its genetic combination. For example, with the increase of F content, the crystallization of feldspar is inhibited to some extent, which is beneficial to the crystallization of timely, topaz and mica. Can we infer from this that B may have a similar effect? That is to say, a considerable amount of B will also inhibit the crystallization of feldspar, expand the timely crystallization field and increase the stable area of tourmaline. In other words, only timely and tourmaline are precipitated, just like the rocks in Tibet. It goes without saying that this needs to be confirmed by relevant experimental petrology.

The supercooled crystallization experiment of magma reveals that its mineral morphology is mostly fibrous, spherical, bunchy and feather-like. Tourmaline in Tibetan rocks has roughly the same shape.

To sum up, according to the occurrence, characteristic structure and structure of rocks, referring to the experimental data of diagenesis and mineralization of boric acid-rich rock system, and referring to the examples that foreign scholars have also found that calcium carbide and tourmaline of magmatic origin were generated in the open system, it is considered that the micro-electric Shi Ying produced in the blasting breccia tube in Mangzong and other places in eastern Tibet was transformed into Washan magma by boric acid-containing magma in the later stage of evolution, because the internal pressure was much greater than the external pressure. Initiating blasting in a limited space (compared with blasting products directly entering the atmosphere), Washan magma quickly condenses and crystallizes and cements breccia to explain its formation mechanism, which is not only in line with geological phenomena, but also strongly supported by relevant diagenetic and metallogenic experimental data.

6. Petrological location and classification of rocks in Tibet.

The Classification Committee of Igneous Rocks of the International Union of Geosciences (SSIR) defines that "Volcanic rocks refer to igneous rocks with cryptocrystalline texture (i.e., fine-grained rocks, most of which can't be recognized by naked eyes), which usually contain vitreous and are related to volcanic activities. This kind of rock can be ejected from the surface in the form of lava flow, or invaded to high places in the form of dikes, bedrock and rock necks. "[1]. The overall characteristics of Tibetan rocks basically conform to this definition. SSIR also defines that "pyroclastic rocks are rocks formed by the direct product of volcanic activity" and "when most of them are in a consolidated state, they can be called pyroclastic rocks" [1]. The basic characteristics of most reservoir rocks fully conform to this definition. On this basis, Tibetan rocks can be further divided into: felsic pyroclastic rocks and felsic fused (rhyolite) rocks.

SSIR stipulates that one of the principles of igneous rock classification is that rock identification is mainly based on mineral composition [12]. In view of this, with reference to the ratio of tourmaline to timely (if the mineral content can be measured by tools), Tibetan stones can be subdivided into tourmaline Xipiyan (tourmaline: timely ≥4), timely: tourmaline ≥4), narrow-sense Tibetan stones (timely: tourmaline ≈ 1) and several transitional types. The first three kinds of rocks are developed in different degrees in the east and west of Tibet. For example, when timely and tourmaline gather into layered patterns respectively, from a certain point of view, timely stripes can be regarded as timely hidden stones and tourmaline stripes can be regarded as tourmaline hidden stones.

7. Summary

The proposal of (1) felsic volcanic rocks has solid macroscopic and conclusive indoor microscopic evidence, and has obtained strong circumstantial evidence from petrological experimental data.

(2) The attempt to name and classify Tibetan rocks is not only a scientific name, but also an attempt to obtain relevant information from its classification status and deepen the understanding of acid igneous rocks and metallogenic regularity.

(3) The genetic mechanism of reservoir rocks does not deny the role played by alteration such as electric Shi Ying, but emphasizes the concrete analysis of specific problems to avoid blindly abusing and exaggerating the diagenetic and metallogenic significance of metasomatic alteration such as electric Shi Ying.

(4) The discovery and preliminary study of Dianying volcanic rocks and hidden rocks show that Professor Lebas, the chairman of SSIR, is quite insightful in the following statement: "As new rock types are continuously discovered or new characteristics of rocks are continuously recognized, the existing classification will always be revised or new classification will appear to adapt to the new situation" [1].