1. The subalkaline nature of the lava indicates a lower silica content compared to alkaline lavas.
熔岩的次碱性表明与碱性熔岩相比，它的二氧化硅含量较低。

2. This particular rock is characterized by its subalkaline composition and high magnesium content.
这种特定的岩石以其次碱性成分和高镁含量而闻名。