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雷州半岛英峰岭火山岩中单斜辉石巨晶以低Mg~#值(0.62～0.47)、贫重稀土(HREE)和富Al_2O_3、TiO_2、Na_2O和中稀土(MREE)为特征,并具有明显的成分变化。随着Mg~#降低,单斜辉石的Al_2O_3(11.58～6.97％)、TiO_2(2.28～1.06％)和HREE逐渐降低。这种变化特征不同于世界上大多数辉石巨晶的变化规律。随着演化辉石巨晶的大多数不相容元素,如Nb、Sr、Zr、Hf和LREE-MREE逐渐增加。低的Mg~#值和Ni、Co、Cr含量指示巨晶母岩浆是一种强烈演化的残余岩浆(Mg~#=0.27～0.35)。分离结晶模拟表明本研究最富镁的巨晶(Lz-54)的母岩浆很可能是由拉斑玄武质岩浆经70～80％以单斜辉石为主的结晶分异后形成。而本研究的其它辉石巨晶是该母岩浆在不同演化阶段(25～80％)分离结晶的产物。分离矿物中除了单斜辉石还包含了大量的石榴子石、斜长石和钛铁矿。温压计算表明英峰岭巨晶是高温岩浆在56～60 km深的上地幔的结晶产物 (T=1290℃～1130℃,P=1.73～1.83GPa),这一深度有利于石榴子石结晶。对比不同地区辉石巨晶的成分特征和形成条件,作者指出不同地区单斜辉石巨晶各种元素的不同变化规律主要受母岩浆成分和结晶条件控制。巨晶母岩浆在地幔结晶时对围岩橄榄岩进行了不同程度的交代作用。早期贫流体的岩浆对橄榄岩的交代作用较?
The clinopyroxene giants in the Yingfengling volcanic rocks of Leizhou peninsula are characterized by low Mg ~ # values (0.62-0.47), heavy and weak rare earths (HREEs) and Al 2 O 3, TiO 2, Na 2 O and medium rare earths (MREEs) Variety. With the decrease of Mg ~ #, the contents of Al_2O_3 (11.58 ~ 6.97%), TiO_2 (2.28 ~ 1.06%) and HREE in clinopyroxene decreased gradually. This change is different from the characteristics of most of the world’s pyroxene giant changes. With the evolution of most of the incompatible elements, such as Nb, Sr, Zr, Hf and LREE-MREE, gradually increased. Low Mg ~ # values and Ni, Co and Cr contents indicate that the giant-grained mafic magma is a strongly evolved remnant magma (Mg ~ # = 0.27-0.35). Separation crystallization simulations indicate that the parent magma of the magnesium-rich giant magnetite (Lz-54) in this study is probably formed by the crystallization of stratiformism basaltic magma after 70-80% dominated by clinopyroxene. However, the other pyroxene macrostructures in this study are the products of the crystallization separation of the parent magma at different evolution stages (25 ~ 80%). In addition to the clinopyroxene mineral separation also contains a large number of garnet, plagioclase and ilmenite. Temperature-compression calculations show that the Yingfengling megacrysts are the crystallization products of high-temperature magma in the upper mantle of 56-60 km depth (T = 1290-1130 ℃, P = 1.73-1.83 GPa), which is beneficial for garnet crystallization . Comparing the composition characteristics and formation conditions of pyroxene crystals in different regions, the authors point out that the different variation rules of various elements of the clinopyroxene macrostructure in different areas are mainly controlled by the parent magma composition and the crystallization conditions. Jurassic magma in the mantle crystallization on peridotite peridotite metasomatism to varying degrees. Early dilute fluid magmatic peridotite metasomatism than?