Mafic Rock

Mafic or Basaltic Rock

基性或玄武岩

The class of rock which crystallizes from silicate minerals at relatively high temperatures is sometimes referred to as "mafic" rock. It is also sometimes called basaltic since the class includes basalt and gabbro. It is in a high temperature range of the Bowen reaction series.

能从硅酸盐矿物中结晶形成的岩石，有时被称为‘镁质’岩石。它也常被称为基性岩，因为该类岩石包括玄武岩和辉长岩。它位于 Bowen 反应系列的高温范围内。

The term "mafic" is a short form indicator of the presence of a relatively large concentration of iron and magnesium. The term "ferromagnesian" is also used.

'玄武质'一词是表示存在相对较多的铁和镁的一种简写术语。'铁镁质'一词也常被使用。

An interesting comment from Bjornerud's "Reading the Rocks" gives some perspective ".. one of the first questions to pose to an igneous rock is where it falls on the spectrum from primitive, or mafic (magnesium-rich, silicon-poor), to evolved, or felsic (magnesium-poor, silicon-rich). A mafic rock like basalt generally has tales to tell of life in the mantle, while for a felsic rock like granite, whose progenitors were themselves crustal, the mantle is a nearly forgotten ancestral homeland."

Bjornerud在《读岩石》中的一段评论提供了一些视角：‘对一种火成岩的第一个问题可能是它在从原始的、基性（镁含量高、硅含量低）到演化了的、酸性（镁含量低、硅含量高）的谱系中处于什么位置。像玄武岩这样的基性岩石通常能讲述地幔中的生命故事，而对于像花岗岩这样的酸性岩石，其起源本身来自地壳，因此地幔几乎已成为遗忘的祖先家园。’

Basalt and Gabbro

玄武岩和辉石岩

Basalt is a dark gray to black, fine-grained, volcanic rock. The fine-grained (aphanitic) texture indicates that it is an extrusive rock, formed at or near the surface from volcanic eruptions. It is a major constituent of lava flows on the surface and of the ocean bottoms. It is in fact the most common extrusive igneous rock. It is the major component of volcanic islands like the Hawaiian Islands and Iceland. Large portions of the states of Oregon and Washington are basalt from the volcanic activity in the region.

玄武岩是一种暗灰色到黑色的细粒（显隐质）火山岩。细粒（显隐质）的结构表明它是一种喷出岩，是在地表或接近地表由火山喷发形成的。它实际上是地表 lava 流和海底的主要组成部分。事实上，它是最常见的喷出岩。它也是火山岛如夏威夷群岛和冰岛的主要组成部分。美国俄勒冈州和华盛顿州的大部分地区都是由该地区火山活动形成的玄武岩。

Basalt is typically composed of pyroxene and calcium-rich plagioclase with lesser amounts of olivine and amphibole. This fits the position in the Bowen reaction series associated with mafic rocks. Basalt with a porphyritic texture is also found, associated with partial crystallization at depth and then eruption from the surface. In these cases, the larger crystals (phenocrysts) tend to be olivine or light-colored calcium feldspar.

玄武岩通常由辉石和富含钙的斜长石组成，其中还含有较少的橄榄石和角闪石。这符合与基性岩相关的 Bowen 反应系列中的位置。此外，也发现有斑状结构的玄武岩，这些岩石与深度部分结晶后喷发到地表有关。在这些情况下，较大的晶体（斑晶）往往为橄榄石或浅色的钙质长石。

Gabbro can be considered to be roughly the same as basalt in compostion, but different in texture. With larger crystals, gabbro is typical of an intrusive rock, formed deep within the Earth. Its texture is called phaneritic. Pyroxene and calcium-rich plagioclase are its major constituents.

辉石岩可以被视为成分大致与玄武岩相似，但质地不同。具有较大晶体的辉石岩典型地属于侵入岩，是在地球内部深处形成的。其质地称为phaneritic。辉石和富含钙的斜长石是其主要成分。