Mineralogical Staday On The Garnet Megacrysys In The Cenozoic Basalts From Hannuoba Of Zhang Bei

Hannuoba region widely distributed Cenozoic basalts, these basalt cracked during the ascent of a large mantle xenoliths, as we study the chemical composition of the upper mantle, formation and evolution provide direct samples. Quantity Zhangbei area enclaves and rich types, predecessors of the different types of inclusions and mineral giant crystal undertaken extensive research. But Garnet inclusions and giant crystal less study. This article focuses on the pomegranate Megacrysts conduct mineralogical, geochemical aspects. Using electron microprobe and single rare earth mineral trace laser-ICP-MS analysis test, the causes of pomegranate extract contained in megacrysts of information. Estimate and use associated minerals clinopyroxene pomegranate Megacrysts formation temperature and pressure, to study the causes of garnet.1. Based on the major elements of garnet studies show that this area has a rich pomegr anate Megacrysts magnesium, aluminum, calcium and iron poor characteristics. Through th e calculation of the area of end-member component shows that pyrope is 64.08%-65.05%, accounting for the vast majority; almandine 19.02%-20.35%, Grossular 12.21%-13.23%, c alcium and iron garnet 1.17%-3.29%; spessartine 0.52%-0.78%, without calcium chromiu m garnet. It can be concluded that this area is pyrope garnets.2. The District pomegranate Megacrysts pro stone elements, Cs no abnormal, Rb, Ba, U showed enrichment enrichment, Th showed a loss; high field strength elements, Ta, Zr, Hf showed enrichment, Nb showed a loss; excessive element V showed enrichment, Sr, Cr, Co, Ni showed a loss. Pro-stone elements in the whole rock, Rb, Cs, Ba, Sr, Th, U showed strong enrichment; high field strength elements, Ta, Zr, Hf showed strong enrichment; excessive element, V performance enrichment, Sr showed slight losses, Co showed a loss, Cr, Ni showed strong losses.Garnet whole rock and transition elements have different degrees of loss, indicating th e type and quantity of the large area part of a higher degree of melting or fractional crystalli zation of basaltic magma phase.3. The paper selected garnet- clinopyroxene thermometer thermometer and two pyroxene, garnet formation temperature estimated and combined with previous results obtained garnet equilibrium temperature of 938-1084 ℃, combining eastern curve of temperature pressure to obtain the garnet is formed 1.16GPa-1.99 GPa, D conversion relationship according to the depth and pressure = 4.02 0.03 P found that the formation depth 38.83km-63.72 km. Depth origin Hannuoba basalt area of at least 64km...