相对年龄测定花岗岩深成岩体的地球科学堆栈交换江南电子竞技平台江南体育网页版 最近30从www.hoelymoley.com 2023 - 04 - 16 - t10:17:52z //www.hoelymoley.com/feeds/question/7034 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/7034 4 相对约会的花岗岩深成岩体 汉娜 //www.hoelymoley.com/users/4941 2015 - 12 - 06 - t04:50:34z 2015 - 12 - 06 - t21:39:51z < p >选择样本的地下水花岗岩深成岩体,这网站是一个更好的网站收集样本,该中心,顶部或侧面?为什么这个网站是一个更好的选择吗?你会推荐哪约会方法,为什么?< / p >

I know that it is better to get a sample from the middle but I'm stuck answering the last two questions.

Any help would be appreciated!

 //www.hoelymoley.com/questions/7034/-/7040 # 7040 2 回答的戈登•斯坦格相对约会花岗岩深成岩体 戈登斯坦格 //www.hoelymoley.com/users/4507 2015 - 12 - 06 - t10:44:52z 2015 - 12 - 06 - t10:44:52z < p >你试图衡量究竟是什么?一些伟大的北美和安第斯岩基冷却至少有2000万年的历史,甚至超过5000万年。也许不合适的结晶过程有一个约会。本文顶部附近的深成岩体是冷却器,但可能沉到更深层次的地方部分再吸收或披着斗篷的在多个周期,导致本文划。它可以是一个非常漫长的过程。一般来说,后期伟晶岩,丰富的挥发物压低融化温度,将表明结晶的年轻时代。更深层次的岩浆库会老,但是真的需要研究的具体领域关系,包括接触变质带的程度决定最适当的年轻或年长的样本。中间很可能会给一个合理的平均日期。记住,你测量的时候,矿物通过关闭温度的冷却,将略明显小于其结晶。< / p >

As to the method of isotopic dating, K-Ar is generally OK but the relative error bounds get worryingly large for dates < a million years. Ar-Ar is more precise but more expensive. It's also an excellent method, as is Rb-Sr, especially for really old precambrian plutons - provided the sample is fresh. Any weathering or diagenesis messes up the method.

//www.hoelymoley.com/questions/7034/-/7043 # 7043 1 答案由Gimelist相对约会花岗岩深成岩体 Gimelist //www.hoelymoley.com/users/725 2015 - 12 - 06 - t21:38:42z 2015 - 12 - 06 - t21:38:42z < p >更好的网站为样本集合的访问网站,可以拿一个样本。除非你有一个钻机或挖掘机,你只能暴露出来。如果你仍然可以访问深成岩体的几个区域,全拿走。样品越多越好。通过选择不要样品一定带你可能会错过的信息。< / p >

The dating method should be zircon U-Pb dating, unless you have a very good reason why not to. Zircons are stable and robust, and with modern analytical methods it may be possible to resolve more than one age in a single zircon, representing for instance recycled detrital zircons.
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