| 浙闽赣中生代火山岩区构造格局及火山构造发育基本特征 |
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| THE TECTONIC FRAMEWORK OF THE ZHEJIANG-FUJIAN-JIANGXI MESOZOIC VOLCANIC TERRANE AND GENERAL FEATURES OF THE VOLCANIC STRUCTURE |
| The Zhejiang-Fujian-Jiangxi Mesozoic volcanic terrane is considered as an important component part of the tectonovolcanic belt in the east part of China, which is mainly composed of the Late Jurassic-Cretaceous volcanic complexes, containing genetically related various metallic and non-metallic minerals.The terrane, located in southeast China and along the west peri-Pacific tectonic domain, overlaps different tectonic units, such as the Yangtze para-platform and the South China Caledonian fold system in the form of complicated mosaic structure. In this terrane there are various kinds of intermediate-acid volcanic rocks, intrusive rocks and sedimentary rocks. The volcanic rock series can be divided into three cycles (Fig. 1), Different kinds of rocks and different lithofacies occur in a certain facies sequence and certain associations in the volcanic structure and cycles, constituting a suite of volcanic complexes having genetic and tempo-spatial relations.The said terrane is complicated in structure and characterized by the development of volcanic structures of different orders and different types. With due consideration of the tectonic control of volcanism and the structural control of the formation of volcanic regions and volcanoes the authors suggest a classification of the volcanic structures in a broad sense into 5 orders (Tables 1, 2) with 14 basic types (and subtypes). Among them, the fifth order (Ⅴ), the vent structure, and the fourth one (Ⅳ), the volcanic apparatus (or volcanis edifice), are the basic units or types. The former comprises calderas (Fig. 8), vents, volcanic domes (Figs. 11, 12) and different types of volcanic passages (Figs. 9, 10), and the latter, volcanic subsidences (Figs. 3, 4), volcano-tectonic depressions (Fig. 5), volcanic sedimentary depressions (Fig. 6) and volcanic uplifts. The grouping of the volcanic units of these two orders make up the third order (Ⅲ), the volcanic eruption region. The second order structure (Ⅱ), the volcanic activity belt, is composed of volcanic eruption regions, and the first order (Ⅰ), the tectono-volcanic belt, is, in turn, composed of second order structures or units.The present reseach reveals that the volcanic terrane under investigation in general belongs to a Ⅰ-order tec tono-volcanic belt, whose tectonic framework shows a complicated pattern formed by overlapping and connection of a series of arcuate faults parallel roughly to the boundary of the Wuyi uplift and the NE-trending faults nearly parallel to the axis of the Wuyi uplift and volcanic structures of different stages, orders, types and combination patterns are distributed in the composite tectonic system. The volcanic pattern is characterized by a combination of arcuate, linear, ring-like, patternoster and equidimensional configurations. It is to a certain extent genetically related to the regional tectonic system but not in full harmony with the latter, showing circular, zonational and mosaic structures characte- ristic of a volcanic terrane.The tectono-volcanic belt (Ⅰ) in question consists of two volcanic activity belts (Ⅱ), including six volcanic eruption regions Ⅲ, nearly seventy volcanic apparatuses (Ⅳ) and more than sixty vent structures (Ⅴ) (Table 2). They are formed during the polycyclic and multistaged late Mesozoic volcanism mainly of central or fissure-central eruption nature with well-defined geomor-phological, geophysical and geochemical indications and often exhibiting rather diversified, complicated structures and evolutionary histories and their close genetic relationship with many mineral deposits of, the terrane. |
| WANG Zhong-jie,YANG Qin-fang,RUAN Hong-hong.1988.THE TECTONIC FRAMEWORK OF THE ZHEJIANG-FUJIAN-JIANGXI MESOZOIC VOLCANIC TERRANE AND GENERAL FEATURES OF THE VOLCANIC STRUCTURE[J].Acta Geoscientica Sinica,10(1):49-72. |
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