中文：

页岩变质后是什么岩石？这是一个有趣的问题，因为它涉及到地质学中的岩石转变过程。当页岩受到高温和高压等外部作用时，会发生变质作用，转变为一种新的岩石。根据不同的变质条件，页岩变质后的岩石类型会有所不同。

在高温和低压条件下，页岩变质后通常会形成泥岩或砂岩。这是因为高温会使页岩中的有机物质分解，释放出大量的气体和液体，同时页岩中的矿物成分也会发生重结晶和重组合。这些变化导致页岩中的物质逐渐转化为新的岩石类型，通常是泥岩或砂岩。

而在高温和高压条件下，页岩变质后则更可能形成片麻岩或大理岩。这是因为高温和高压会使得页岩中的矿物成分发生明显的重结晶和重组合，形成新的矿物晶体和岩石结构。这些变化导致页岩中的物质逐渐转化为片麻岩或大理岩。

总的来说，页岩变质后形成的岩石类型取决于变质的条件。不同的变质条件会导致不同类型的岩石形成，这体现了地质学的多样性和复杂性。

英文：

What kind of rock will shale metamorphose into? This is an interesting question because it involves the process of rock transformation in geology. When shale is subjected to external forces such as high temperature and high pressure, metamorphism occurs and it transforms into a new type of rock. The type of rock formed after the shale metamorphosed depends on the metamorphic conditions.

Under high temperature and low pressure conditions, shale metamorphosed usually forms into mudstone or sandstone. This is because high temperature causes the organic matter in the shale to decompose, releasing a large amount of gas and liquid, while the mineral composition in the shale also undergoes recrystallization and reorganization. These changes cause the substances in the shale to gradually transform into new rock types, usually mudstone or sandstone.

Under high temperature and high pressure conditions, shale metamorphosed is more likely to form into gneiss or marble. This is because high temperature and high pressure cause the mineral composition in the shale to undergo significant recrystallization and reorganization, forming new mineral crystals and rock structures. These changes cause the substances in the shale to gradually transform into gneiss or marble.

Overall, the type of rock formed after shale metamorphosed depends on the metamorphic conditions. Different metamorphic conditions lead to the formation of different types of rocks,体现了the diversity and complexity of geology.