任务：
检查岩石： 描述你在花岗岩中看到的奇石的颜色、大小和质地。它们与周围的花岗岩有何不同？它们的结构或颜色是否明显？
岩石与熔岩： 解释为什么花岗岩中的奇石没有被周围的岩浆融化。是什么特性保护了它们不被熔化？
奇石的地质意义： 考虑一下花岗岩中的奇石揭示了这一地区的地质历史。地质学家可以从这些包裹体中收集到哪些信息？
可选项： 为自己和/或遗址中的物品拍一张照片。
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玩得开心
陨石是火山爆发时被困在岩浆中的外来岩石包裹体，为了解地球地质历史提供了宝贵的资料。本 EarthCache 将带您前往花岗岩中发现异长石的地点。花岗岩是由地表深处的岩浆缓慢冷却形成的，当岩浆上升时，陨石就会被困住。
什么是异长岩？
异长石 “一词源于希腊语，意思是 ”外来的石头“（来自 ”xenos“=外来，”lithos"=石头）。异岩石是不属于岩浆本身的岩石碎片，而是来自更深的地层。在火山喷发过程中，岩浆会将这些岩石碎片从地幔或地壳中向上携带，然后到达地表并凝固。
这些包裹体的成分往往与周围的火山岩有很大不同，可能由更古老的物质组成。这为地质学家提供了一个无需深入钻探就能研究地球深层的机会。
碎屑岩的形成：
岩浆上升： 来自地幔的岩浆通过地壳的薄弱地带上升。
陨石被捕获： 岩浆在上升的过程中会携带深层的岩石碎片。
凝固： 当岩浆到达地球表面并冷却时，外来岩石被捕获，并以异形石的形式留在火山岩中。
花岗岩中的异岩石：
花岗岩是一种火成岩，主要由石英、长石和云母组成。花岗岩中的异岩石可能是玄武岩或页岩等更古老岩石的碎片。这些析出岩通常表现为独特的岩石碎片，因其质地、颜色或结构而从周围的物质中脱颖而出。与花岗岩不同的是，它们通常颜色较深，颗粒较粗，因此很容易被发现。
Tasks:
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Examine the Xenoliths: Describe the color, size, and texture of the xenoliths you see in the granite. How do they differ from the surrounding granite? Are they noticeable in structure or color?
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Xenolith vs. Lava: Explain why the xenoliths in granite were not melted by the surrounding magma. What properties might have protected them from melting?
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Geological Significance of Xenoliths: Consider what xenoliths in granite reveal about the geological history of this area. What information can geologists gather from these inclusions?
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Optional: Take a photo of yourself and/or an item at the site.
Please send your answers to the questions to silka03.earthcache@gmail.com. Do not include them in your log!
You can log immediately after submitting your answers. You don't need to wait for log approval!
Have fun!
Xenoliths are foreign rock inclusions that were trapped in magma during a volcanic eruption, providing valuable insights into the Earth's geological history. This EarthCache takes you to a location where xenoliths are found in granite. Granite forms by the slow cooling of magma deep beneath the Earth's surface, and xenoliths can become trapped as the magma rises.
What are Xenoliths?
The term "xenolith" comes from Greek and means "foreign stone" (from "xenos" = foreign and "lithos" = stone). Xenoliths are rock fragments that do not belong to the magma itself but originate from deeper Earth layers. During a volcanic eruption, magma can carry these rock pieces from the mantle or the Earth's crust upwards before it reaches the surface and solidifies.
These inclusions often differ significantly in composition from the surrounding volcanic rock and may consist of much older material. This provides geologists with an opportunity to study deeper layers of the Earth without the need for deep drilling.
The Formation of Xenoliths:
- Magma rises: Magma from the Earth's mantle rises through weak zones in the Earth's crust.
- Xenoliths are captured: On its way up, the magma carries rock fragments from deeper layers with it.
- Solidification: When the magma reaches the Earth's surface and cools, the foreign rock is trapped and remains as a xenolith in the volcanic rock.
Xenoliths in Granite:
Granite, an igneous rock, is primarily composed of quartz, feldspar, and mica. Xenoliths found in granite can be fragments of much older rocks like basalt or shale. These xenoliths often appear as distinct rock fragments that stand out from the surrounding material due to their texture, color, or structure. Unlike granite, they are often darker and coarser-grained, making them easy to spot.
picture: https://www.mineralienatlas.de/lexikon/index.php/BilderGeordnet?lang=en&rockid=141
https://de.wikipedia.org/wiki/Xenolith
https://www.mineralienatlas.de/lexikon/index.php/Xenolith?lang=de