實(shí)習(xí)五巖漿巖

1、實(shí)習(xí)五實(shí)習(xí)五 巖漿巖（一）巖漿巖（一） 中酸性巖中酸性巖 目的：目的：1、學(xué)會(huì)巖石的鑒定和描述方法、學(xué)會(huì)巖石的鑒定和描述方法 2、掌握巖漿巖的結(jié)構(gòu)、構(gòu)造類(lèi)型、掌握巖漿巖的結(jié)構(gòu)、構(gòu)造類(lèi)型 3、認(rèn)識(shí)幾種主要的巖漿巖類(lèi)巖石、認(rèn)識(shí)幾種主要的巖漿巖類(lèi)巖石 內(nèi)容：內(nèi)容：1、觀(guān)察并描述：花崗巖、似斑狀觀(guān)察并描述：花崗巖、似斑狀 花崗巖、花崗斑巖、流紋巖、花崗巖、花崗斑巖、流紋巖、 偉晶巖、浮巖等偉晶巖、浮巖等 2、觀(guān)察：細(xì)晶巖、黑曜巖、珍珠巖、觀(guān)察：細(xì)晶巖、黑曜巖、珍珠巖、 花崗閃長(zhǎng)巖等花崗閃長(zhǎng)巖等巖石 Rocks 巖石：礦物的天然混合物或集合體。巖石：礦物的天然混合物或集合體。 Rocks are nat

2、ural mixtures or Rocks are natural mixtures or aggregates of mineralsaggregates of mineralsHow to Identify Rocks Rocks can be classified as igneous, metamorphic, or sedimentary according to the manner in which they were formed. Their specific characteristics depend on the minerals that constitute th

3、em. Based on this information, it is possible to know how rocks gained their color, texture, and crystalline structure. With a little experience and knowledge, people can learn to recognize and identify some of the rocks that they often see.Color The color of a rock is determined by the color of the

4、 minerals that compose it. Some colors are generated by the purity of the rock, whereas others are produced by the impurities present in it. Marble, for instance, can have different shades if it contains impurities.Texture Texture refers to the size and arrangement of grains that form a rock. The gr

5、ains can be thick, fine, or even imperceptible. There are also rocks, such as conglomerates, whose grains are formed by the fragments of other rocks. The texture is a small-scale property of a rock, but determined many of its large-scale properties.Mineral Composition Rocks are natural combinations

6、of two or more minerals. The properties of rocks will change in accordance with their mineralogical composition. For instance, granite contains quartz, feldspar, and mica; the absence of any of these elements would result in a different rock.The Three Great Rock Families 三大巖類(lèi)：三大巖類(lèi)： Sedimentary：沉積巖：沉

7、積巖 Has obvious stratification 層理 Very soft (easily scratched by a knife) 軟 Obviously made of particles cemented together 碎屑被膠結(jié)在一起 Contains fossils 化石Igneous-Volcanic火山巖火山巖 Contains numerous bubble-like cavities that may or may not be lined with minerals 氣孔 Has obvious bubbly or frothy texture 氣孔 Is

8、fine-grained, uniform in texture, and hard 細(xì)粒、均勻、堅(jiān)硬 Glassy or highly vesicular rocks are almost always igneous Igneous-Plutonic侵入巖侵入巖 Made of discrete mineral grains locked together (may be loosened by weathering) Contains large crystals in a finer-grained mass Rock mass obviously cuts across other

9、rock structures. Metamorphic變質(zhì)巖變質(zhì)巖 Has a fine texture with an obvious directional grain (foliation) 定向 Has obvious bands, streaks or clumps of different minerals 不同礦物的條帶 Is made mostly of quartz or calcite but is coarse-grained and lacks sedimentary features 石英方解石 Contains distinctive metamorphic mi

10、nerals like garnet or kyanite 特殊的變質(zhì)礦物 May often have features of original rock but is recrystallized or chemically changed. Igneous Rocks and Magma 火成巖和巖漿火成巖和巖漿火成巖的產(chǎn)狀分類(lèi)噴出巖噴出巖火山火山巖巖侵入巖侵入巖深成巖深成巖侵入巖淺成巖侵入巖淺成巖5kmIgneous Rocks are formed by crystallization from a liquid, or magma. They include two types：

11、Volcanic or extrusive igneous rocks form when the magma cools and crystallizes on the surface of the Earth Intrusive or plutonic igneous rocks wherein the magma crystallizes at depth in the Earth. 巖漿巖的結(jié)構(gòu)巖漿巖的結(jié)構(gòu)巖漿巖的結(jié)構(gòu)巖漿巖的結(jié)構(gòu) 按按照照結(jié)結(jié)晶晶程程度度劃劃分分顯晶質(zhì)結(jié)構(gòu)顯晶質(zhì)結(jié)構(gòu)隱晶質(zhì)結(jié)構(gòu)隱晶質(zhì)結(jié)構(gòu)流紋巖玻璃質(zhì)結(jié)構(gòu)黑曜巖斑狀結(jié)構(gòu)斑狀結(jié)構(gòu)斑狀和似斑狀結(jié)構(gòu)：區(qū)別斑狀和似斑狀結(jié)構(gòu)：區(qū)別主

12、要在基質(zhì)的粒度主要在基質(zhì)的粒度斑狀結(jié)構(gòu)斑狀結(jié)構(gòu)斑晶斑晶基質(zhì)基質(zhì)斑晶斑晶似斑狀結(jié)構(gòu)似斑狀結(jié)構(gòu)斑晶斑晶基質(zhì)基質(zhì)文象結(jié)構(gòu)文象結(jié)構(gòu)(Graphic Texture) 石英呈一定的外形(如象形文字）有規(guī)律地鑲嵌在鉀長(zhǎng)石中。Some Igneous Rocks Are Named on Textural Criteria結(jié)構(gòu)構(gòu)造的命名結(jié)構(gòu)構(gòu)造的命名 Scoria: Porous 火山渣 Pumice 浮巖 Obsidian - Glass黑曜巖 Tuff - Cemented Ash 火山灰 Breccia - Cemented Fragments 角礫巖 Pegmatite - Extremely La

13、rge Crystals 偉晶巖 Aplite - Sugary Texture, Quartz & Feldspar 細(xì)晶巖 Porphyry - Fine Matrix, Large Crystals 斑巖巖石的構(gòu)造巖石的構(gòu)造 均一塊狀構(gòu)造均一塊狀構(gòu)造 斑雜構(gòu)造斑雜構(gòu)造 條帶狀構(gòu)造條帶狀構(gòu)造 流動(dòng)構(gòu)造流動(dòng)構(gòu)造 氣孔構(gòu)造氣孔構(gòu)造 杏仁構(gòu)造杏仁構(gòu)造 枕狀構(gòu)造枕狀構(gòu)造塊狀構(gòu)造塊狀構(gòu)造 條帶狀條帶狀 構(gòu)造構(gòu)造流紋構(gòu)造氣氣 孔孔 狀狀 構(gòu)構(gòu) 造造杏仁構(gòu)造化學(xué)組成及分類(lèi)化學(xué)組成及分類(lèi) 以氧化物形式表示：如以氧化物形式表示：如SiO2、Al2O3、CaO、Na2O、K2O等等等等 SiO2是最重

14、要的組分，是巖石分類(lèi)的最是最重要的組分，是巖石分類(lèi)的最主要指標(biāo)，可以劃分為：主要指標(biāo)，可以劃分為： 酸性巖，酸性巖， SiO2 65 中性巖，中性巖，65% SiO2 52 基性巖，基性巖，52% SiO2 45 超基性巖，超基性巖， SiO2 45巖石中的礦物組成巖石中的礦物組成 主要為硅酸鹽礦物，分為淺色和暗色兩主要為硅酸鹽礦物，分為淺色和暗色兩類(lèi)：類(lèi)： 淺色礦物：斜長(zhǎng)石、正長(zhǎng)石、石英淺色礦物：斜長(zhǎng)石、正長(zhǎng)石、石英 暗色礦物：橄欖石、輝石、角閃石、暗色礦物：橄欖石、輝石、角閃石、 黑云母黑云母 不同酸性程度的巖石具有特征的礦物組不同酸性程度的巖石具有特征的礦物組成成The geologis

15、t N.L. Bowen found that minerals tend to form in specific sequences in igneous rocks,橄 欖 石輝 石角 閃 石黑 云 母石 英白 云 母鉀 長(zhǎng) 石鈉 長(zhǎng) 石中 長(zhǎng) 石鈣 長(zhǎng) 石巖石的觀(guān)察描述巖石的觀(guān)察描述 細(xì)粒細(xì)粒 顏色顏色 玻璃質(zhì)或隱晶質(zhì)結(jié)構(gòu)玻璃質(zhì)或隱晶質(zhì)結(jié)構(gòu) 構(gòu)造構(gòu)造 粗粒：粗粒： 顏色顏色 結(jié)構(gòu)、構(gòu)造結(jié)構(gòu)、構(gòu)造 主要礦物成分及其鑒定特征和含量主要礦物成分及其鑒定特征和含量 其它其它斑狀結(jié)構(gòu)斑狀結(jié)構(gòu) 顏色顏色 斑狀或似斑狀結(jié)構(gòu)斑狀或似斑狀結(jié)構(gòu) 斑晶：成分及其鑒定斑晶：成分及其鑒定 特征、大小、含量特征、大小、含量 基質(zhì)：特征及含量基質(zhì)：特征及含量 構(gòu)造構(gòu)造 其它其它實(shí)習(xí)五實(shí)習(xí)