The qiongzhong and danxian batholiths , as the largest early mesozoic syntectonic granite intrusions in hainan island , are mainly composed of porphyritic biotite two - feldspars granitoids , in which alkali - feldspar phenocrysts and dark minerals are foliated mostly in we - direction . the granites are of metaluminous i - type . major and trace elements show co - variations with sio2 , suggesting the fractional crystallization of plagioclase , hornblende , apatite and ti - fe oxides in the evolution of the granites 花岗岩的主量元素和部分微量元素成分与sio _ 2呈良好的相关关系，显示出明显的斜长石、角闪石、磷灰石和ti - fe氧化物等的分离结晶作用，总体上它们与大陆岛弧花岗岩的微量元素丰度和分布特征相似，系统地亏损ba 、 nb 、 sr 、 p和ti等元素。
2.
There are three genetic types of mineral deposits in the beiya ore district : cu - au polymetallic deposits related to alkaline porphyries , comprising porphyritic cu - au deposits and polymetallic skarn deposits related to quartz - albite porphyry and quartz - k - feldspar porphyry ; fe - au deposits related to gabbro or basalt magma , consisting of magmatic fe - au deposits and sedimentary polymetallic deposits formed in caves and lakes ; and palaeo - placers formed at the weathering surface , in lakes and in karsts 北衙金矿有3种成因不同的矿床：与碱性斑岩有关的铜金多金属矿，包括与石英钠长斑岩和石英正长斑岩有关的斑岩型铜金矿床和矽卡岩型多金属矿床；与辉长玄武岩浆有关的铁金矿床，包括熔浆型铁金矿床和喷流沉积型多金属矿床，后者又有洞穴和湖相沉积环境之分；及古砂矿，有古风化壳型砂矿、河湖相古砂矿和洞穴沉积古砂矿。
3.
Four major rock types are found within the reserve . from the oldest to the youngest , they are the tuffs with volcanic bombs , granodiorites , porphyritic rhyolites and basaltic dykes , respectively . geomorphologically , the marine reserve has typical exposed rocky shore of south - easterly - directed capes and headlands in hong kong 鹤咀海岸保护区内可以找到四种主要岩石种类，以岩石形成的年代计算，最古老的是火山爆发形成的凝灰岩，然后依次是花岗闪长岩,流纹斑岩及玄武岩。
