Evidence for natural molecular hydrogen seepage associated with Carolina bays (surficial, ovoid depressions on the Atlantic Coastal Plain, Province of the USA)

Viacheslav Zgonnik,Kathleen M Farrell,Nikolay Larin,Daniel Pillot,Eric Deville,Valérie Beaumont

doi:10.1186/s40645-015-0062-5

Abstract

A study of soil gases was made in North Carolina (USA) in and around morphological depressions called “Carolina bays.” This type of depression is observed over the Atlantic coastal plains of the USA, but their origin remains debated. Significant concentrations of molecular hydrogen (H2) were detected, notably around the bays. These measurements suggest that Carolina bays are the surficial expression of fluid flow pathways for hydrogen gas moving from depth to the surface. The potential mechanisms of H2 production and transport and the geological controls on the fluid migration pathways are discussed, with reference to the hypothesis that Carolina bays are the result of local collapses caused by the alteration of rock along the deep pathways of H2 migrating towards the surface. The present H2 seepages are comparable to those in similar structures previously observed in the East European craton.

Highlights

Carolina bays are surficial, consistently oriented, ovalshaped depressions that occur widely across the southeastern Atlantic Coastal Plain, Province of eastern North America (Brooks et al 2010)
The elliptical depressions known as Carolina bays in the USA are associated with H2 flows, as observed in similar surface features in the East European craton
This molecular hydrogen probably originates from geochemical processes taking place under the sedimentary pile and migrates towards the surface

Summary

Introduction

Consistently oriented, ovalshaped depressions that occur widely across the southeastern Atlantic Coastal Plain, Province of eastern North America (Brooks et al 2010). They are well defined on satellite images 2, 3, and 4) and densely cover parts of the Coastal Plain in North Carolina (NC) and South Carolina (SC). They vary in size, ranging from ~100 m to 8 km in diameter (Lake Waccamaw, NC, USA). Elevated rims (~1–3 m), commonly consisting of sand, surround these features. Bays of various sizes may overlap, and small bays are frequently present

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