CaCO₃溶解在碳酸盐补偿深度(CCD)。< / p >

However, this paper suggests that some CaCO₃ can exist below the CCD.

My question arises from a discussion in this answer.

The question is whether some of the CO₂ emitted by volcanoes in subduction zones comes from the melting of CaCO₃ sediments in the slag.

Has there been any isotopic study clarifying the provenance of CO₂ from volcanoes in subduction zones?

我知道有一个主流的答案，认为彩虹沙丘他们可以从地质上解释…我只是想知道是否有可能通过采矿形成这些颜色和沙丘?如果不是，为什么它们看起来和南美的矿坑一模一样?< / p >

我们都知道氧气含量会随着温度的升高和降低，所以我认为假设大气压力也会变化是安全的…由于花岗岩和玄武岩是由热、压和物质冷却形成的。如果大气压力和环境温度不同，有没有可能让花岗岩表现得像粘土一样?会不会有截然不同的条件使花岗岩冷却得如此缓慢以至于可以被塑造?< / p >

长英质岩石含有大量的钠、钾和钙(以及大量的铝)，而镁铁质岩石由大量的镁和铁组成....

为什么?< / p >

Why is magnesium (z=12) in the denser rock(s) with iron (z=26), while aluminum (13) and calcium (20) get stuck nearer the surface with lightweight sodium (11)?

I haven't found a reason for this...

P.S.: What about potassium and sodium? Are they also unable to easily fit into iron rocks as well? After all, they also end up, generally, closer to the surface....

我错过了什么?< / p >

I certainly understand that a combination of their solubility and reasonably high frequency would lead one to expect them to be abundant in sea water, but they are hyper abundant, completely dominating all other salt ions. Iron, for example, is twice as abundant, and potassium only a little less abundant, and fluorine more abundant than chlorine.

Moreover, if the salts are deposited in the ocean through weathering of rocks and deposition via rivers, why does the salinity not simply grow and grow? I understand that some is lost due to tectonic activity, but it seems extraordinarily unlikely that these two forces should be equally balanced, and so we would see a significant change in average salinity over time.

(Please note I am migrating this question from the Chemistry SE at their recommendation.)

我从各种大学推广网站(例如，here和here)读到<强>硼水平将在低有机质的沙质土壤中缺乏。

• 这表明，在有机质(OM)含量高的非沙质土壤中，硼含量高。<李> / < / ul >

  However, in a series of upland forest patches in central NC with clayey (low sand) soils with substantial OM, I've found the opposite to be true: Soil boron-levels in these low sand/high OM plots were regionally amongst the lowest levels measured (<0.2 ppm; more than 4x lower than nearby sandy soils with low OM).

  • This seems to contradict the above stated trend from extension websites.

  Question: What would cause this trend? What would cause boron levels to be so deficient in clayey (non sandy) high OM soil?

  Other information about sites: relatively dry, high topographic position and exposure, acidic (pH < 6) soil, high {K, Al, S} in soil. Vegetation = mid-to-late successional mixed hardwood/oak-hickory forests with relatively open understory due to deer overbrowse.

  _{Note: soil methods: Mehlich III extraction for plant nutrients; loss-on-ignition method for OM.}

<强>当土壤钙含量高时:当土壤风化了大量的碳酸钙基岩时，土壤钙的含量可能会很高。在农业环境中，化肥会导致钙含量过高。在某些粘土中发现相对较高的含量也并不罕见，因为它们的CEC较高。< / p >

• For example, this source (and others) suggest that calcium levels would be expected to be higher in clay vs sand (with some impact from pH):

  Calcium in soil is generally correlated with the amount of sand versus clay in soil as well as soil pH. Sandy soils tend to have calcium levels at or below 1000 lbs/acre, whereas high clay soils often have levels above 2,500 lbs/acre, Soils with a good pH level also tend to have plenty of soil Ca.

My situation: I've found relatively high levels (1200-2000 ppm) of soil calcium (measured by Mehlich III extraction; Mehlich 1984) from fairly non-acidic (pH = 5.5-6.5) alluvial sandy soils.

• the soil type: "Cartecay and Chewacla soils, 0 to 2 percent slopes, frequently flooded" (with perhaps mix of "White Store sandy loam, 10 to 25 percent slopes")

• the site is in a forested urban patch in central North Carolina (USA) and is neighbored by a small 1st order stream that occasionally floods the site after elevated post-storm drainage

For reference, nearby high-clay (more acidic) soils in higher topographic positions tended to have lower calcium levels between 200-1000 ppm.

My question: what would be the source/cause of high calcium in sandy alluvial soils?

• What role does the nearing-neutral pH have?

• Are there likely "natural" (e.g., geologic) sources of heightened calcium in this case, or is this likely a phenomenon due to high calcium effluent from upstream non-point pollution sources (e.g., golf course, hospital, parking lots)?

Update:

I've also now noticed that the soil has many traits (e.g., high pH, Mg, Cu, Fe, Mn, and Zn) that could associate it as being a result of an ultramafic intrusion (known to occur in this general region). However, I know that qualitatively speaking, ultramafic intrusions would have a high Mg/Ca ratio. My soil's ratios (for both A and B horizons):

• ppm_A: 350 ppm Mg / 1800 ppm Ca = 0.19

• ppm_B: 315 ppm Mg / 1150 ppm Ca = 0.27

• percent saturation A: 17% Mg / 50% Ca = 0.34

• percent saturation B: 19% Mg / 38% Ca = 0.5

I'm not sure what constitutes "high" as I'm unsure of a baseline (i.e., is high much greater than a ratio of 1 or simply greater than a ratio of 0?).

Is it possible that this hypothesis holds any weight??

• other issues: do ultramafic intrusions result in sandy alluvial soils?, here suggests there'd be high Na, of which my soil has very low amounts (1/50th of which the linked source suggests).

我在哪里可以找到西班牙土壤中潜在有毒元素的地球化学阈值表?我只看到过一项针对西班牙的有机化合物法令

如果有的话，我认为降低碱度会降低二氧化碳分压。我相信这是因为在恒定的pH值下去除碳酸盐和碳酸氢盐离子(构成碱度)会迫使一些二氧化碳再次溶解到这些离子中，以保持在恒定的pH值下的相对分布，从而降低二氧化碳分压。这种相对平衡如下图所示，摘自Sarmiento(2013)第8章。为什么事实恰恰相反呢?< / p >

Taro Takahashi; Jon Olafsson; John G. Goddard; David W. Chipman; S. C. Sutherland (1993). Seasonal variation of CO₂ and nutrients in the high-latitude surface oceans: A comparative study. , 7(4), 843–0. doi:10.1029/93gb02263

Sarmiento, Jorge L. "Ocean biogeochemical dynamics." Ocean Biogeochemical Dynamics. Princeton University Press, 2013.

在什么条件下你期望找到最多的降水?< / p >

1. A polar air mass of 0 degrees centigrade moving over a great lake that has a water temperature of 10 degrees.

OR

2. A polar air mass of -5 degrees centigrade moving over a great lake that has a water temperature of 5 degrees.

为什么地壳中有铀?和为什么铀只在地壳中，真的吗?铀的化学性质似乎是这样的，它与较轻的元素一起被带到地表，但金的化学性质不是更不利于这种过程吗?这就是为什么在地壳中黄金比铀少500倍吗?< / p >

显然，根据帕克斯过程银在锌中的可溶性是铅的3000倍。那么，为什么大多数银是从方铅矿中获得的呢?< / p >

Edit: “ Silver mainly occurs as a contaminant in chalcopyrite and galena, important ores of copper and lead, respectively.” Silver mining

This Wikipedia page cites a few sources as well. So maybe it isn’t most, but a great deal of it is found in galena.

Also the page for galena mentions that it’s an important source of silver.

What are your experiences, or has an experience abroad been important for your academic career?

I am aware that this question can be closed because of Option Based/OFF TOPIC. But I also didn't want to ask this question on Earth Science Meta, because this question doesn't fit there either!

我正在阅读关于月球地幔中的水，然而它提到了很多逃逸。在这种情况下是什么意思?< / p >

关于这个实验:< a href = " https://www.remineralize.org/rem_publications/action-of-microorganisms-in-basalt-powder/ " rel =“nofollow”noreferrer > https://www.remineralize.org/rem_publications/action-of-microorganisms-in-basalt-powder/ < / > < / p > < p >据说玄武岩岩粉应用于土壤可以提高土壤肥力,特别是如果一个完整的土壤食物网是目前由于细菌和真菌生物风化作用——这有助于释放植物营养交换和可溶池。玄武岩的风化率高吗?它属于“不连续系列”还是“连续”系列?< / p >

Goldich dissolution series

地表水蒸发过程中发生的同位素分馏是平衡分馏还是动力分馏?我的意思是，蒸发可以用瑞利分馏来描述，但我一直认为这只发生在平衡分馏中。但既然我们可以假设水蒸发后被风带走，我们能不能只假设动力分馏?谁有一篇好论文能清楚地解释哪个分馏过程发生在蒸发过程中，哪个发生在冷凝过程中?< / p >

Any insight from research article is appreciated and please do not put simple textbook explanations. Thank you very much.

[1] https://www.epa.gov/sites/default/files/2015-12/documents/1311.pdf

At the end, I performed the sampling like this:

I was asked to perform the sampling at both left and right side of the river (without any detail here) and those sediments will be acid-digested and its heavy metal concentrations will be measured using an atomic absorption spectrophotometer.

Is this sampling acceptable? Is there any reference that this sampling is acceptable or not, considering that struggles before?

Thank you.

回答“岩雾”的本质是什么?在描述月球形成的过程中?解释了什么“;岩雾”;以及科学家如何使用这个概念来理解行星，在这种情况下，月球的形成也是如此。< / p >

Turning rock into vapor in a controlled way in order to study how it cools and the chemical reactions that take place and the types and nature of materials that reform sounds like quite a technical challenge, but probably necessary to at least test or calibrate simulations of the process on a large scale.

So I'd like to ask:

Question: Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?

If the answer to the first part is yes, answers that discuss other and perhaps more fundamental experiments done with rock vapor are certainly welcome!

背景

我读了(我能理解的)这篇文章其中作者Yuan和Steinle-Neumann "使用先进的量子力学模拟硅酸盐和金属熔体，显示在高压和高温下，氢越来越多地融入到硅酸盐金属中，这是地核形成的条件。因此，在地核中氢的丰度很高。[…地球早期的吸积事件，特别是岩浆海洋的形成，对地球的化学演化和热演化有很大的影响。在岩浆海洋阶段，金属从硅酸盐中分离形成核，从地幔中除去了铁和镍以外的元素[…]。轻元素如H、C、O和Si是这一过程的结果。这篇文章接着提出了一个模型，解释了地球表面的轻元素如何最终被运输到核心，留下一个主要是硅酸盐的地壳，其中轻元素和金属主要被运输到核心:轻元素在高压下与铁形成弱键，并与铁在重力作用下分选。“我们发现氢在低压(20gpa和2500k)下是弱亲铁性的，随着压力的增加，亲铁性变得更强，这表明氢在核心分离过程中大量被输送到核心，并且在那里是稳定的。”

<强>问题

在行星吸积盘的近真空中弥散的氢最初是如何被化学或引力束缚在形成中的地球上的?据我所知，被提议纳入核心的机制必须有极端的压力和温度——这很好地解释了它是如何从熔融表面深处到达核心的，但似乎不适合行星的形成。为什么被原始地球带走的氢没有像进入地球时一样迅速地从上层大气中蒸发掉，而永远不会在足够的压力下与铁形成化学结合?在我看来，氢的中间化学键转变成不易挥发的形式可以解释这一点。我在其他地方读到过，地球上的水在吸积过程中被冲走的很少，但也许硅烷和烷烃或其他富氢化合物可能在吸积盘中形成，被冲走，然后在吸积行星的极端环境中被分解并与其他化学物质重新结合。 Or there might have been enough free Si, C, and other chemicals with an affinity for hydrogen in the atmosphere or surface of proto-Earth to bond with hydrogen, and then break up when convected down into higher temperature and pressure regimes. My chemistry knowledge is pretty weak, so I don't know if either explanation is plausible.

Follow-up question: given our current known reserves of transuranic elements and again taking into account their decay products, where will the greatest uranium reserves be in, say, 10 half-lives of U-238? I can barely make sense of a nuclide chart and don't even know where to begin looking for a map of these elements.

我想了解为什么在一个湖泊沉积物核心层中的任何以下条件似乎暗示了湖泊在相关时间是低的:

1. 低C/N比率
2. 低δ¹³C
3. 低磁性颗粒浓度

我遇到的所有论文都假设了关于这些关系的先前知识，像维基百科这样的基本来源也没有帮助我。我的专业是数学，几乎没有化学知识。

我试图确定矿物的抗压强度是什么针铁矿和磁铁矿。我所做的研究没有一项是有成果的。我有发现:

• 多项研究关于将针铁矿混合到水泥中对水泥抗压强度的影响

• 多项研究关于岩石和矿石的抗压强度，这些岩石和矿石中偶然有一些针铁矿或磁铁矿，除了其他矿物

• 一些关于磁铁矿在与其他材料结合时在生物医学植入物中使用的研究

• 多项关于针铁矿如何影响土壤力学特性的研究，其中只提到土壤的力学特性和抗压强度，而不是它的单个成分

• 一项研究涉及在帽贝牙齿只提到所述帽贝牙齿的抗拉强度，而不是针铁矿的抗压强度

• 没有研究或信息可以告诉我针铁矿的抗压强度是什么