Discovery of especially large bubble-like miarolitic granites in Laoshan and its geological and geomorphic significance
Recently, some especially large bubble-like miarolitic caves in A-type granites in Laoshan have been discovered with the largest diameter of up to 3.1 m, far exceeding the granitic miarolitic caves previously reported, thus adding new knowledge to geology. This helps to study the primary environment for granites formed in Laoshan and also reveal genesis of “natural-mortar” micro-landform for granites in Laoshan. The existence of a new genesis type—“bubble-like miarolitic caves” of speleology is also confirmed by this discovery. Especially large bubble-like miarolitic caves are rare geological relics with high ornamental, science and tourism value.
The Type and Evolution of the Granite Landforms in China
With the subtropical monsoon climate in southern China,the planation surface and the crust of weathering developed into many particular granite landform types,such as that on Mt.Huangshan and Mt.Sanqingshan,as a result of the uplift and down-cut in the following tectonic movements.In this paper,the temporal and spatial development discipline of the granite crust of weathering and landform was discussed,and the close relationship between the landform age and planation surface was studied.The connections of the granite landform and the crust of weathering were also put forward in different uplift background.Based on that,the uplift extent of massifs can be presumed,which would be ～200 m at coastal region,and increase to 1600-2000 m at the Nanling Mountains or Dabie Mountain and Funiu Massif.
Changes in Quartz During Heating and the Possible Effects on Si Production
In Si and FeSi production, the main Si source is SiO2, in the form of quartz. Reactions with SiO2 generate SiO gas that further reacts with SiC to Si. During heating, quartz will transform to other SiO2 modifications with cristobalite as the stable high-temperature phase. Transformation to cristobalite is a slow process. Its rate has been investigated for several industrial quartz sources and has been shown to vary considerably among the different quartz types. Other differences in behavior during heating between these quartz sources, such as softening temperature and volume expansion, have also been studied. The quartz-cristobalite ratio will affect the rate of reactions involving SiO2. The industrial consequences and other implications of the observed difference between quartz types are discussed. Initial studies of industrial quartz were published by Ringdalen et al. In the current work, a new experimental method has been developed, and an investigation of several new quartz sources has confirmed the earlier observed large variation between different sources. The repeatability of the data has been studied and the effect of gas atmosphere investigated. The results from the earlier work are included as a basis for the discussion.