The Origin of Nanoscopic Grooving on Vesicle Walls in Submarine Basaltic Glass: Implications for Nanotechnology

Jason E French,Karlis Muehlenbachs

doi:10.1155/2009/309208

Abstract

Dendritic networks of nanoscopic grooves measuring 50–75 nm wide by<50 nm deep occur on the walls of vesicles in the glassy margins of mid-ocean ridge pillow basalts worldwide. Until now, their exact origin and significance have remained unclear. Here we document examples of such grooved patterns on vesicle walls in rocks from beneath the North Atlantic Ocean, and give a fluid mechanical explanation for how they formed. According to this model, individual nanogrooves represent frozen viscous fingers of magmatic fluid that were injected into a thin spheroidal shell of hot glass surrounding each vesicle. The driving mechanism for this process is provided by previous numerical predictions of tangential tensile stress around some vesicles in glassy rocks upon cooling through the glass transition. The self-assembling nature of the dendritic nanogrooves, their small size, and overall complexity in form, are interesting from the standpoint of exploring new applications in the field of nanotechnology. Replicating such structures in the laboratory would compete with state-of-the-art nanolithography techniques, both in terms of pattern complexity and size, which would be useful in the fabrication of a variety of grooved nanodevices. Dendritic nanogrooving inSiO2glass might be employed in the manufacturing of integrated circuits.

Highlights

Vesicles in the glassy margins of submarine pillow basalts can exhibit a range of internal features that collectively record information pertaining to eruption dynamics, deformational history, the composition of magmatic fluids linked with ore deposits of economic importance, and the explosive behaviour of some “popping rocks” upon dredging from the ocean floor [1,2,3,4,5,6]
There is enough information within the interrelated dendritic patterns of grooves on the vesicle wall in Figure 1 to conclude that they represent viscous fingering trees
The grooves themselves represent fingers of very low-viscosity (∼4·10−5 Pa · s for CO2 vapour at 30 MPa and 600–700◦C [28]) magmatic fluid that were injected into a shell-like boundary layer of hot (∼600– 700◦C across the glass transition for basalt [29]) dehydrating basaltic glass with much higher relative viscosity (∼109 to ∼1011 Pa · s across the glass transition for basalt [29]) that seems to have acted as a ∼50 nm thick, natural example of a Hele-Shaw cell

Summary

Introduction

Vesicles in the glassy margins of submarine pillow basalts can exhibit a range of internal features that collectively record information pertaining to eruption dynamics, deformational history, the composition of magmatic fluids linked with ore deposits of economic importance, and the explosive behaviour of some “popping rocks” upon dredging from the ocean floor [1,2,3,4,5,6]. Sulfide spherules commonly decorate vesicle interiors, in between which may occur complex dendritic patterns of nanoscopic (

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