📚 沉积岩：一层一层的历史书📚 Sedimentary Rock: A History Book in Layers
上一片里，火成岩是岩浆冷却结成的“速冻岩石”。可山崖上的岩石一层一层、薄厚分明像书页——它们不是冻出来的，而是一粒粒碎屑“堆”出来的。🌍 蓝色星球向导翻开这本历史书，带你追踪一粒沙的旅行。Last time, igneous rock froze out of cooling magma like ice cubes. But cliff rocks come in neat layers like book pages — never frozen, just piled up grain by grain. 🌍 Your blue-planet guide opens this history book and follows one grain of sand on its journey.
第 1 步：先变碎，再上路——风化与搬运Step 1: Break up, then hit the road — weathering and transport
整块岩石，怎么变成一粒粒碎屑？How does solid rock become loose grains?
高山岩石被风吹、日晒、冻裂，一块块剥落成碎屑，这叫“风化”。雨水汇成河流，像传送带一样搬运它们。🌍 向导划着小船跟拍：越往下游，碎屑被磨得越圆越小——记住口诀：越远颗粒越细。Mountain rock is pried apart by wind, sun, and frost into loose debris — that is “weathering”. Rain gathers into rivers that carry it all away like a conveyor belt. 🌍 Your guide floats alongside: the farther downstream, the rounder and smaller the grains — remember: finer, farther out.
碎屑被冲进大海后，去哪儿了？Once debris reaches the sea, where does it go?
第 2 步：一层层铺下——沉积与层理Step 2: Laid down layer by layer — settling into strata
河水一慢下来，碎屑就往下沉：粗的先落，细的后落，一年一年铺成平整地层。每一层就是书的一页，最底下那页最老。运气好的话，这一页还夹着贝壳——它们就是未来的化石。As river water slows, debris sinks: coarse grains land first, fine ones later, paving flat layers year after year. Each layer is a page, and the bottom page is the oldest. Lucky pages trap seashells — tomorrow's fossils.
松散沙层一捏就散，怎么变成硬邦邦的石头？Loose sand falls apart in your hand — how does it turn to solid stone?
第 3 步：压紧成岩——化石被封存Step 3: Squeezed into rock — fossils sealed inside
新地层越堆越厚，把老地层压得严严实实，矿物“胶水”还把碎屑粘在一起，这叫“成岩”。砂岩粗粒、页岩薄页、石灰岩最爱藏化石——🌍 向导举起放大镜：认出这三位，沉积岩全家你就认全了。New layers pile up and squeeze the old ones tight, while mineral “glue” cements every grain — that is how rock is made. Sandstone is coarse, shale splits into thin sheets, limestone loves hiding fossils — 🌍 your guide raises a magnifier: know these three and you know the whole family.
🎮 沉积实验室：亲手堆一座地层（30 秒）🎮 Deposition Lab: stack your own strata (30 seconds)
道理讲完了。先调碎屑大小和堆积速度，铺三层、压成岩；再过 3 关顺序考题。Theory done. Tune grain size and speed, lay three layers, squeeze them into rock; then clear 3 ordering quizzes.
一句话记住它：沉积岩 = 碎屑被搬运、沉积、压紧粘成的层状岩石，层理是书页，化石是书签。Remember it in one line: sedimentary rock = debris carried, settled, and glued into layered rock — layers are the pages, fossils are the bookmarks.
风化变碎 → 河流搬运 → 入海沉积 → 压紧成岩，顺序别颠倒Weathering → transport → settling → compaction, in that order越远颗粒越细；最底下的地层最老Finer grains farther out; the bottom layer is the oldest page砂岩粗、页岩薄、石灰岩藏化石Coarse sandstone, thin-sheeted shale, fossil-hiding limestone
内容参考 OpenStax 等公开教材，多来源核对 · AI 生成、人工审核 · 发现错误欢迎指正，帮这片叶子长得更好。Based on OpenStax and other open textbooks, cross-checked across sources · AI-generated, human-reviewed · Spotted a mistake? Tell us — help this leaf grow.
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