That the zircons get younger from core to rim is expected because zircon crystals grow concentrically by adding material to their grain boundary.

• 锆石自核心向表面，年龄越来越年轻，这现象其实是预料中的事，因为锆石结晶是从中心开始长大的，不断添加物质在结晶的表面上。