Spots:玄武岩
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Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
Strict Standards: Non-static method MagicWord::get() should not be called statically, assuming $this from incompatible context in /var/www/html/mediawiki/includes/Parser.php on line 1952
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| Revision as of 16:19, 31 March 2006 Smilelong (Talk | contribs) ← Previous diff |
Current revision Smilelong (Talk | contribs) 玄武岩 moved to Spots:玄武岩 |
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- 名字：玄武岩 Basalt
- 組成：輝石、長石、橄欖石。
- 特性：
為基性岩漿噴發所成的熔岩流凝固而成之火成岩，分佈甚廣顏色為黑暗灰褐及暗紅等色，比重為2.9~3.2玄武岩常成岩流、岩堵或侵入岩層產出，岩流常具胞狀或熔滓狀構造。台灣之玄武岩種類甚多，主要為普通玄武岩、橄欖石玄武岩、紫蘇輝石玄武岩、及玻璃質玄武岩等，六角柱狀節理為其特徵。
- 產狀：
大部分海洋地殼皆由玄武岩造成，岩理有成緻密狀者，亦有成為多孔狀者，後者的孔隙常有方解石、石英等充填而成杏仁狀構造。經風化作用後，生成粘土或紅土。玄武岩與安山岩同為台灣分佈最廣而出產較多之火成岩。
- 產地：大屯山火山群，海岸山脈，澎湖群島。
- 說明：
玄武岩是一種地下岩漿從火山中噴出或從地表裂隙中溢出凝結形成的火成岩。
玄武岩的主要成分是矽鋁酸鈉或矽鋁酸鈣，二氧化矽的含量大約是45-52%，還含有較高的氧化鐵和氧化鎂，是一種細粒緻密的黑色岩石。由於噴發時產生大量氣孔，有時是大孔如杏仁狀構造，後來中間常被其他礦物充填。玄武岩岩漿的黏度小，易於流動，形成很大的覆蓋層，常形成廣大的熔岩臺地，所以分佈很廣。
玄武岩根據其成分不同可以分為拉斑玄武岩、鹼性玄武岩、高鋁玄武岩；按其結構不同可分為氣孔狀玄武岩、杏仁狀玄武岩、玄武玻璃；按其充填礦物不同可分為橄欖玄武岩、紫蘇輝石玄武岩等。
沒有被風化的玄武岩是黑色或暗綠色的緻密岩石，由於其凝結後產生六方晶體節理，被風化後形成六方柱狀，風化厲害可以形成黃褐色的玄武土，如果進一部被雨水淋濾，除去二氧化矽形成鋁土礦。有的玄武岩氣孔中還充填有銅、鈷、硫磺等礦物。
由於玄武岩融化後黏度小，凝結後堅硬緻密，所以可以做鑄石的原料。
