近日，挪威奥斯陆大学Razvan Caracas团队揭示了富含挥发物的金伯利岩融化、岩浆上升和捕获体运输的浮力。该研究于2025年8月21日发表在《地质学》杂志上。

金伯利岩熔体是地幔源碳和氢的主要载体，在地球深部碳循环和钻石运输中起着重要作用。它们的低密度、低粘度和蒸气溶出性使其能够快速上升。从上地幔上升，金伯利岩熔体融合了捕虏体和异晶体，并释放了挥发物。这些过程改变了它们的初始成分，增加了原始金伯利岩岩浆和到达地表的岩浆之间的差异。

为了解释金伯利岩火山作用，研究组分析了不同挥发性成分的金伯利岩熔体的原子差异和密度。他们表明，水使熔体更具差异，这也应该降低它们的粘度。所有的金伯利岩熔体都在较低的大陆嵴（MOHO不连续面）以下正浮力。它们需要~ 8.2%的二氧化碳才能穿过MOHO并上升。在MOHO之上，最富挥发物的金伯利岩熔体可携带高达44%的贫橄榄岩型xenolithic碎片。

附：英文原文

Title: Buoyancy of volatile-rich kimberlite melts, magma ascent, and xenolith transport

Author: Ana Anzulovi, Anne H. Davis, Carmen Gaina, Razvan Caracas

Issue&Volume: 2025-08-21

Abstract: Kimberlite melts are primary carriers of mantle-derived carbon and hydrogen, playing an important role in Earth’s deep carbon cycle and diamond transport. Their low densities, viscosities, and vapor exsolution enable fast ascent rates. Ascending from the upper mantle, kimberlite melts incorporate xenoliths and xenocrysts and exsolve volatiles. These processes alter their initial composition, increasing the discrepancy between the proto-kimberlite magma and the magma that reaches the surface. To explain kimberlite volcanism, we examine atomic diffusivities and densities of kimberlite melts with varying volatile contents. We show that water makes the melts more diffusive, which should also lower their viscosity. All our kimberlite melts are positively buoyant below the lower continental crust (the MOHO discontinuity). They require ～8.2 wt% CO2 to cross and rise through the MOHO. Above the MOHO, the most volatile-rich kimberlite melts can carry up to ～44% xenolithic fragments of depleted peridotite type.

DOI: 10.1130/G53387.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53387.1/660734/Buoyancy-of-volatile-rich-kimberlite-melts-magmaredirectedFrom=fulltext