Sintering of vesiculating pyroclasts
Sintering of vesiculating pyroclasts
复制标题
多孔火山碎屑的烧结
DOI：
10.1016/j.epsl.2023.118410
复制
发表时间：
2023
影响因子：
5.3
通讯作者：
Weaver J
中科院分区：
文献类型：
--
作者：
Weaver J
炽热的火山碎屑可以同时烧结、起泡和放气——这是一个几乎不受约束的过程组合。然而，这种过程的组合可以在火山碎屑密度流沉积期间、在管道填充的火山碎屑碎片和凝灰岩中同时发生。在许多这样的环境中，烧结驱动的渗透率演化是气体通过演化沉积物输送的关键。在这里，我们从实验和理论上研究了在实验条件下含水且过饱和的热碎片火山系统烧结过程中渗透性网络的演变。首先，我们发现，随着气泡生长驱动颗粒彼此膨胀，破坏相互连接的孔隙，气泡化导致颗粒间多孔网络关闭。其次，我们观察到通过扩散到颗粒边缘之外的脱气导致囊泡颗粒收缩，重新打开它们之间的孔隙空间。因此，我们发现，在烧结过程中，囊泡和扩散脱气竞争决定了片段内的囊泡性和渗透性。碎片内囊泡的发展直接影响碎片间的孔隙空间及其连通性，在囊泡化过程中孔隙空间及其连通性减少，随后在扩散放气过程中增加，从而促进复杂的非线性渗透率演变。这些过程的相对优势取决于碎片尺寸；相应地，由于表面积与体积之比较大，细碎片在扩散除气过程中比粗碎片以更高的速度失去气体。随着系统的进展，较大的碎片保留了更高比例的气体，因此比较细的碎片获得了更大的泡孔，因此，粗碎的火山碎屑在连通孔隙度和渗透率方面经历了更大但短暂的减少。我们认为，在囊泡充分的情况下，它可以比仅烧结系统更早地导致连通孔隙率的完全丧失和可渗透通道的密封。我们的结果表明，必须修改经典的烧结模型以解释这些气泡化和扩散脱气过程，并且只有组合的气泡化、烧结和扩散脱气模型才能解决热碎屑火山系统中渗透率的演变。
Hot volcanic pyroclasts can sinter, vesiculate, and outgas in concert – a combination of processes which remains poorly constrained. And yet this combination of processes can occur coincidently during deposition from pyroclastic density currents, in conduit-filling pyroclastic debris, and in tuffisites. In many of these settings, it is the sintering-driven evolution of permeability that is key to gas transport through the evolving deposit. Here, we experimentally and theoretically investigate the evolution of the permeable networks during sintering of hot fragmental volcanic systems, which are hydrous and oversaturated at the experimental conditions. Firstly, we find that vesiculation results in shutting of the inter-granular porous network as bubble growth drives expansion of the particles into one another, destroying interconnected pores. Secondly, we observe that degassing by diffusion out of the particle edge results in contraction of the vesicular particles, re-opening pore spaces between them. Therefore, we find that vesiculation, and diffusive outgassing compete to determine both the intra-fragment vesicularity and the permeability during sintering. The development of intra-fragment vesicularity directly impacts the inter-fragment pore space and its connectivity, which decreases during vesiculation and subsequently increases during diffusive outgassing, prompting complex, non-linear permeability evolution.The relative dominance of these processes is fragment size dependent; proportionally, fine fragments lose gas at a higher rate than coarser fragments during diffusive outgassing due to larger surface area to volume ratios. As the systems progress, larger fragments retain a higher proportion of gas and so attain greater vesicularities than finer ones – and therefore, the coarse fragmental pyroclasts experience a greater, yet transient, reduction in connected porosity and permeability. We suggest that where vesiculation is sufficient, it can lead to the complete loss of connected porosity and the sealing of permeable pathways much earlier than in a sintering-only system. Our results suggest that classical sintering models must be modified to account for these vesiculation and diffusive degassing processes, and that only a combined vesiculation, sintering, and diffusive outgassing model can resolve the evolution of permeability in hot clastic volcanic systems.
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影响因子：
0.9
作者：
F. Wadsworth;C. Vossen;Diana Schmid;M. Colombier;M. Heap;B. Scheu;Donald Bruce Dingwell
通讯作者：
Donald Bruce Dingwell
DOI：
10.1098/rspa.2015.0780
发表时间：
2016-04
期刊：
Proceedings. Mathematical, physical, and engineering sciences
影响因子：
--
作者：
Wadsworth FB;Vasseur J;Llewellin EW;Schauroth J;Dobson KJ;Scheu B;Dingwell DB
通讯作者：
Dingwell DB
使用原位 X 射线断层扫描验证火山系统中灰烬颗粒焊接的通用模型
影响因子：
5.3
作者：
Wadsworth, Fabian B.;Vasseur, Jérémie;Schauroth, Jenny;Llewellin, Edward W.;Dobson, Katherine J.;Havard, Tegan;Scheu, Bettina;von Aulock, Felix W.;Gardner, James E.;Dingwell, Donald B.
通讯作者：
Dingwell, Donald B.
聚结颗粒介质中的拓扑反转控制流体流动状态。
DOI：
10.1103/physreve.96.033113
发表时间：
2017
期刊：
Physical review. E
影响因子：
--
作者：
F. Wadsworth;J. Vasseur;E. Llewellin;K. Dobson;M. Colombier;Felix W. von Aulock;J. L. Fife;S. Wiesmaier;K. Hess;B. Scheu;Y. Lavallée;Donald Bruce Dingwell
通讯作者：
Donald Bruce Dingwell
影响因子：
2.9
作者：
Kendrick, Jackie E.;Lavallee, Yan;Vasseur, Jeremie
通讯作者：
Vasseur, Jeremie