(Table 1) Geochemistry of sector-zoned crystal at DSDP Hole 45-395A

Variations in crystal morphologies in pillow basalts and probable sheet flows sampled from the region of the East Pacific Rise drilled during Leg 54 are related both to differences in composition and to an extreme range of cooling rate experienced upon extrusion. The basalts range in composition from olivine-rich tholeiites to tholeiitic ferrobasalts, and include some more alkaline basalts. The kinetics of crystal growth in some samples appears to have been influenced by the amount of initial superheating (or supercooling) of the magma, or possibly by differential retention of volatiles. Olivine in quartznormative ferrobasalts apparently formed metastably at high undercooling. […]

在第54航次（Leg 54）钻探的东太平洋海隆（East Pacific Rise）区域采集的枕状玄武岩（pillow basalts）及疑似席状岩流中，晶体形态的变化既与成分差异相关，也与喷发时经历的极宽范围冷却速率密切相关。该区域玄武岩的成分范围涵盖富橄榄石拉斑玄武岩（olivine-rich tholeiites）至拉斑质铁质玄武岩（tholeiitic ferrobasalts），同时包含部分碱性更强的玄武岩（alkaline basalts）。部分样品的晶体生长动力学似乎受岩浆初始过热度（superheating）或过冷度（supercooling）的影响，也可能与挥发分（volatiles）的差异留存有关。石英标准型铁质玄武岩（quartznormative ferrobasalts）中的橄榄石显然是在高过冷（undercooling）条件下亚稳形成的。[…]