The hypothetical FHQ buffer was suggested by Giggenbach (1987) as a “non-specific” redox buffer containing fayalite as a proxy for Fe 2+ and hematite as a proxy for Fe 3+. It is intended to approximate rock-buffering conditions in volcanic systems, and occasionally called the …

In geology, a redox buffer is an assemblage of minerals or compounds that constrains oxygen fugacity as a function of temperature. Knowledge of the redox conditions (or equivalently, oxygen fugacities) at which a rock forms and evolves can be important for interpreting the rock history.

2019年4月23日 · Oxygen fugacity (f O 2) is a fundamental thermodynamic property governing redox potential in solid Earth systems. Analysis of magmatic f O 2 aids our understanding of the valence state and solubility of multivalent elements during magma evolution.

比如，在800℃，IW线上垂直做竖直线的交点对应横坐标的值即为对应的lgfO2的值，就是buffer在这一温度下的绝对痒逸度的值。 如果，我是说如果，这个时候已知测得的实际的绝对氧逸度的值，另一个logfO2，二者作差即为相对氧逸度。

2013年5月29日 · The tool Calculate fO2 Buffer allows you to determine the “delta” of a several oxygen fugacity buffers (for example: ΔNNO, ΔQFM, etc.) when the value of logfO2 is known. Here’s a screenshot of the inputs and outputs:

2018年3月9日 · 从自然铁（Fe），方铁矿（FeO），磁铁矿（FeO.Fe2O3）到赤铁矿（Fe2O3），反映fO2愈来愈高。 岩浆氧逸度是制约Cu、Au成矿的重要因素之一，Cu、Au为亲硫元素，岩浆结晶分异过程中如果S2－大量存在就会导致Cu、Au硫化物过饱和而过早沉淀，不利于残余岩浆中Cu、Au的富集和晚阶段含Cu、Au岩浆流体的形成，因而不利于Cu、Au矿床的形成。 高氧逸度条件下，岩浆中的硫绝大多数以SO42－和SO2形式溶解在硅酸盐熔体中，硫化物难 …

2013年12月9日 · The coexistence of a metal and its oxide at equilibrium constitutes an oxygen buffer which can be used to control or calculate fO2 in high pressure experiments. Application of 1-bar buffers to high pressure conditions can lead to inaccuracies in fO2 calculations because of unconstrained pressure dependencies.

2015年1月15日 · Results for the fO2 sensors are in good agreement with the intended fO2 established by the buffer, demonstrating excellent control for durations of 24–48 h, with uncertainties less than ± 0.3 log bar units of fO2.

2022年12月1日 · Tool to calculate oxygen fugacity in terms of the common buffers when logfO2 is known or for translating between fO2 values expressed in terms of various buffers. This is useful for converting calculated oxygen fugacity values into …

氧逸度（fO2）就是有效的氧分压。 氧分压是指混合气体总压之下的氧的分压力，以PO2表示。 举一个最简单的例子来说, 如果把空气的总压力看作是一个大气压, 而空气的主要组成是O2约占体积21%, N2约占体积79%, 因此, 它们的分压力为PO2=0.21atm,N2=0.79atm 。对于理想气体, 氧逸度就是氧分压。对于实际气体, 则氧逸度是校正后的有效氧分压。所以, fO2=γPO2,γ为校正系数, 也叫逸度系数。它的大小与温度、压力以及气体本身的性质有关。愈是低压、高温的条件,分子之 …