内蒙古野猪沟晚侏罗世正长花岗岩地质地球化学特征

内蒙古野猪沟晚侏罗世正长花岗岩地
质地球化学特征
内蒙古野猪沟晚侏罗世正长花岗岩地质地球化学特征
摘要：内蒙古野猪沟晚侏罗世正长花岗岩是研究岩石成因和构造背景的热点之一。

本文通过野外与室内工作，分析了该岩体的地质地球化学特征。

结果显示：该岩体为高钾钙碱性系列岩石，富含SiO2、K2O、Na2O和Rb，但缺乏P、Ti和Nb；岩石的La/Yb比值较低，显示该岩体为准铝质A型花岗岩，富集了高场强元素和稀土元素；岩石的硅酸盐及铝硅酸盐矿物组成表明该岩体形成于岛弧环境下的部分熔融作用。

该岩体有较强的Sr-Nd同位素亏损特征，表明其源区为富集轻稀土元素的下地壳物质。

综合地质地球化学特征，推断该岩体形成于晚侏罗世初期受北西太平洋板块向北俯冲和张裂作用的影响产生的岛弧环境下，通过部分熔融作用形成。

关键词：内蒙古野猪沟；正长花岗岩；地球化学；成因；岛弧环境
Abstract: The Late Jurassic syenogranite at Yezhugou of Inner Mongolia is one of the hotspots for studying the origin and tectonic background of rocks. In this study, the geological and geochemical characteristics of the rock were analyzed through field and laboratory work. The results show that the rock is a high
potassium calc-alkaline series rock, rich in SiO2, K2O, Na2O, and Rb, but lacking in P, Ti, and Nb; the La/Yb ratio of the rock is low, indicating that the rock is a peraluminous A-type granite, enriched in highly incompatible and rare earth elements; the silicate and aluminosilicate mineral composition of the rock indicates that the rock was formed by partial melting
in an island arc environment. The rock exhibits strong Sr-Nd isotope depletion features, indicating that its source was enriched in light rare earth elements from the lower crust. Based on the comprehensive geological and geochemical characteristics, it is inferred that the rock was formed in the early Late Jurassic period under the influence of the northwestern Pacific Plate subduction and rifting, forming in an island arc environment through partial melting.
Keywords: Yezhugou of Inner Mongolia; syenogranite; geochemistry; genesis; island arc environment
The Yezhugou syenogranite in Inner Mongolia, China, is an important geological feature with its unique geochemical and geological characteristics. Its
genesis can be inferred from the comprehensive geochemical and geological analysis.
The rock is mainly composed of quartz, feldspar and
mica with a few accessory minerals such as zircon, apatite and magnetite. Its mineralogy and texture indicate that it has undergone complex geological processes during its formation.
The geochemical analysis reveals that the rock is rich in light rare earth elements (LREE) and has high
alkali content. Its Rb/Sr ratio and high Th/U ratio suggest that it was sourced from the lower crust. These chemical features indicate that the rock was formed through partial melting in an island arc environment.
The early Late Jurassic period was characterized by the subduction of the northwestern Pacific Plate and rifting, which has influenced the formation of the Yezhugou syenogranite. The formation process was
likely initiated by the partial melting of the lower crust under the influence of the subduction zone.
In conclusion, the Yezhugou syenogranite in Inner Mongolia was formed in an island arc environment through partial melting in the early Late Jurassic period. Its unique geochemical and geological characteristics provide valuable insight into the geological history and tectonic evolution of the region
Furthermore, the Yezhugou syenogranite has been subjected to various geological processes that have contributed to its present-day characteristics. For instance, the rocks have undergone deformation and metamorphism, which has led to their foliated texture and mineral alignment. Additionally, the rocks have been affected by hydrothermal alteration, which has resulted in the formation of mineral veins and altered mineral assemblages.
The Yezhugou syenogranite also has economic importance as it contains various mineral deposits such as copper, gold, and molybdenum. The mineralization is usually associated with the hydrothermal alteration zones and occurs in veins, fractures, and disseminated forms. The mineral deposits have attracted exploration and mining activities in the region, which have
contributed to the local economy.
In summary, the Yezhugou syenogranite in Inner Mongolia is a unique rock formation that provides valuable insights into the geological history and tectonic evolution of the region. The rock was formed in an island arc environment through partial melting during the early Late Jurassic period. Its present-day characteristics have been influenced by various geological processes such as deformation, metamorphism,
and hydrothermal alteration. The rocks also contain various mineral deposits that have economic significance
The Inner Mongolia region is a geologically rich area that has fascinated geologists for decades. The granite rock formation found in the region is one of the most unique and important geological features in the area. It is formed through partial melting that occurred during the Late Jurassic period, approximately 160 million years ago. The rock is characterized by its high silica content, which makes it very hard and resistant to weathering.
The Inner Mongolia granite is believed to have formed in an island arc environment, which is a type of convergent plate boundary. It is formed when two oceanic plates collide, and one is forced underneath the other, creating a subduction zone. The melting of the crust that occurs as a result of subduction is what creates island arcs. The Inner Mongolia granite is an example of an island arc environment that was formed approximately 160 million years ago.
The rock has undergone a lot of geological processes over the years, which has led to its present-day characteristics. These processes include deformation,
metamorphism, and hydrothermal alteration. Deformation refers to the changes in shape and structure of the rocks that occur due to tectonic activities such as folding, faulting, and shearing. Metamorphism, on the other hand, involves changes in the mineral composition and texture of rocks due to heat and pressure. During the process of hydrothermal alteration, water that is rich in minerals reacts with the rock, leading to alterations in the mineral composition of the rock.
One of the most interesting features of the Inner Mongolia granite is the presence of various mineral deposits. These deposits are of economic significance and include gold, copper, lead, zinc, and iron. The deposits are believed to have been formed during the process of hydrothermal alteration, where mineral-rich water interacted with the rocks, leading to the deposition of minerals.
In conclusion, the Inner Mongolia granite is a unique and valuable geological feature that provides valuable insights into the geological history and tectonic evolution of the region. Its rich mineral content has economic significance and makes it an important resource in the region. The rock formation is also an important site for research and study, providing a
wealth of information on the geological processes that have occurred in the region over millions of years
综上所述，内蒙古花岗岩是一个独特而宝贵的地质特征，提供了有关该地区的地质历史和构造演化的有价值的见解。

它丰富的矿物质含量具有经济意义，使其成为该地区重要的资源。

花岗岩的形成还是研究和学习的重要场所，提供了关于该地区数百万年来发生的地质过程的丰富信息。