Rocks are everywhere! They are large and small, heavy or light, porous or dense, but rocks

岩石到處都找得到！他們有大有小、有重有輕、有疏鬆有密實，

in some shape or form can be found all over the planet. Different types of rock are formed

但所有形狀或質地的岩石在所有行星上都找得到，不同類型的岩石形成方式也不一樣

in different ways. There are three main types of rock: Igneous, Sedimentary, and Metamorphic.

主要有三種：火成岩、沉積岩和變質岩

Igneous is a word that means 'fiery.' Igneous rock is formed when magma or lava cools. Sometimes

Igneous (火成岩) 意思就是「熾熱的」。火成岩是岩漿或熔岩冷卻形成的

magma cools slowly underneath the earth's surface. This forms intrusive igneous rock,

有時岩漿慢慢在地表下冷卻，這就會形成侵入岩（內部火成岩），

like granite. Other times lava cools when it comes to the surface in a volcanic eruption.

像是花崗岩。如果火山爆發岩漿在地表冷卻，

This forms extrusive igneous rock. Some examples of extrusive igneous rock are tuff, obsidian,

就會形成火山岩 (外部火成岩)。屬於火山岩的有凝灰岩、黑曜石

and pumice. Igneous rocks make up about 95% of the earth's crust.

和浮石。火成岩由 95%的地球板塊所組成

The next type of rock is Sedimentary rock. Sediment is small particles of sand, mud,

下一個類型是沉積岩。沉澱物是沉澱在水底、土地下 (通常在湖泊和海洋裡) 的

and organic material that settle to the bottom of water or land areas, often lakes or oceans.

砂石、泥土和有機物的小顆粒

Sedimentary rocks are formed when sediment accumulates over time in deposits that form

沉積岩是經由歲月累積逐漸堆疊形成的岩層

layers. These layers become squeezed and compressed over time until they consolidate into a rock.

這些岩層隨著時間逐漸變緊實、壓縮，直到他們壓成一塊岩石

Sedimentary rocks are the types of rocks in which fossils may be found, since the process

沉積岩是有可能找到化石的岩層種類，因為沉積岩的形成過程中

of forming sedimentary rocks can preserve plant and animal remains that are deposited

可以將一起被沉澱的動植物保存進岩層裡。

into the sediment layers. Some examples of sedimentary rock are limestone, shale, and

屬於沉積岩有石灰岩、頁岩

sandstone.

和砂岩。

The third type of rock is Metamorphic rock. The word 'metamorph' means to change form,

第三種岩石是變質岩。 "metamorph" 的意思就是質地改變，

and metamorphic rock is rock that has been changed by extreme heat and pressure. Sedimentary

而變質岩是一種被極高的溫度和壓力所改變而成的岩石

rock, igneous rock, or even other metamorphic rocks can be changed by heat and pressure

沉積岩、火成岩或甚至是變質岩本身都可以因熱和壓力而改變成另一種新的岩石

into new kinds of rock. Metamorphic rocks can be formed by being deep under the earth,

變質岩在高壓高溫的地球深處形成，

where pressure and temperatures are high, or when rock near the surface is heated up

或是當岩石表面被移動的板塊或岩漿加熱，也可以形成變質岩

by the movement of tectonic plates or magma. Different types of rocks become different

當暴露在熱和壓力下，不同種類的岩石會變成不同種類的變質岩

types of metamorphic rock when exposed to heat and pressure. For example, shale becomes

舉例來說，頁岩會變成板岩

slate, sandstone becomes quartzite, and limestone becomes marble.

砂岩會變成石英岩，而石灰岩會變成大理石

Rocks are slowly but constantly changing in something known as the 'rock cycle.' The rock

岩石會緩慢但持續的改變，這是所謂的「岩石循環」，

cycle begins with magma, or hot melted rock, deep beneath the earth's surface. This magma

岩石循環始於岩漿，也就是地表深處的熔岩

becomes crystallized, becoming igneous rock. These rocks begin to erode, or break down

岩漿開始結晶，變成火成岩

into small pieces because of wind, water, or other forces. The small fragments of rock

這些岩石開始因為風、水或是其他外力被侵蝕或是崩解成小碎石

are carried away as sediment when water passes over them and are deposited in layers which

當水流過，這些小石頭碎片會被帶走然後沉澱

eventually become sedimentary rocks. Then, some sedimentary rocks are pushed below the

最後變成沉積岩。接著，一些沉積岩經由板塊活動被推到地表之下，

surface due to tectonic activity, where they are exposed to heat and pressure, transforming

暴露在高溫、高壓下，轉變成變質岩

them into metamorphic rocks. If the rocks are buried even deeper, they may melt and

如果岩石被推得更深，它們可能會融化

form magma, starting the cycle all over again. Of course, sedimentary and metamorphic rocks

形成岩漿，重新開始岩石循環的過程。當然，沉積岩和變質岩

can be eroded into sediment, and igneous rock can become metamorphic rock or lava, but one

也會被腐蝕成沉積岩，火成岩也可能變成變質岩或是熔岩，

way or another, rocks all over the world keep changing from one form to the next.

但不管如何，全世界的岩石會持續不斷的改質變化下去