Ancient Earth Research Articles

Expanding Earth and declining gravity: a chapter in the recent history of geophysics

Abstract. Although speculative ideas of an expanding Earth can be found before World War II, it was only in the 1950s and 1960s that the theory attracted serious attention among a minority of earth scientists. While some of the proponents of the expanding Earth adopted an empiricist attitude by disregarding the physical cause of the assumed expansion, others argued that the cause, either fully or in part, was of cosmological origin. They referred to the possibility that the gravitational constant was slowly decreasing in time, as first suggested by P. Dirac in 1937. As a result of a stronger gravitation in the past, the ancient Earth would have been smaller than today. The gravitational argument for an expanding Earth was proposed by P. Jordan and L. Egyed in the 1950s and during the next 2 decades it was discussed by several physicists, astronomers and earth scientists. Among those who for a period felt attracted by "gravitational expansionism" were A. Holmes, J. Tuzo Wilson and F. Hoyle. The paper examines the idea of a varying gravitational constant and its impact on geophysics in the period from about 1955 to the mid-1970s.

Upper-mantle anisotropy beneath the south Indian Shield: Influenced by ancient and recent Earth processes

Upper-mantle anisotropy beneath the south Indian Shield: Influenced by ancient and recent Earth processes

Upper-mantle anisotropy beneath the south Indian Shield: Influenced by ancient and recent Earth processes

ABSTRACT We obtained shear-wave splitting parameters from core-refracted phases like SKS, SKKS, and PKS at 75 digital broadband seismic stations almost uniformly spread over the south Indian Shield representing varied geological terrains, including the western Dharwar craton, the eastern Dharwar craton, the Southern granulite terrain, and the continental margins along the west and east coasts. A majority of the sta-tions over the Dharwar craton show delay times of 1–1.6 s, indicative of a 150–200-km-thick anisotropic layer correlating with the lithospheric root, while segments like the Pan-African Southern granulite terrain have delay times of 0.5–0.7 s, suggesting an internally deformed and thin anisotropic layer, possibly due to recent plate-tectonic and geodynamic processes. The average direction of anisotropy is generally ~N30°E, correlating with the present-day plate motion, with local deviations where the direction of anisotropy correlates with the orienta-tion of the regional shear zones. Stations close to the continental margin show large time delays (up to 2 s) with the fast axis parallel to the rift axis. Further, we infer a layered anisotropic lithosphere in the south Indian Shield as revealed in 90° periodicity of the two anisotropy parameters (fast direction and delay time). The upper lithosphere represents the depleted Archean mantle, while the lower lithosphere could be transformed to more fertile mantle due to subsequent deformation. This study suggests that the observed anisotropy over the south Indian Shield is the result of complex interplay between the architecture of an Archean craton and its subsequent deformation in different geological domains due to deep Earth processes.

Atmospheric record in the Hadean Eon from multiple sulfur isotope measurements in Nuvvuagittuq Greenstone Belt (Nunavik, Quebec)

Mass-independent fractionation of sulfur isotopes (S-MIF) results from photochemical reactions involving short-wavelength UV light. The presence of these anomalies in Archean sediments [(4-2.5 billion years ago, (Ga)] implies that the early atmosphere was free of the appropriate UV absorbers, of which ozone is the most important in the modern atmosphere. Consequently, S-MIF is considered some of the strongest evidence for the lack of free atmospheric oxygen before 2.4 Ga. Although temporal variations in the S-MIF record are thought to depend on changes in the abundances of gas and aerosol species, our limited understanding of photochemical mechanisms complicates interpretation of the S-MIF record in terms of atmospheric composition. Multiple sulfur isotope compositions (δ(33)S, δ(34)S, and δ(36)S) of the >3.8 billion-year-old Nuvvuagittuq Greenstone Belt (Ungava peninsula) have been investigated to track the early origins of S-MIF. Anomalous S-isotope compositions (Δ(33)S up to +2.2‰) confirm a sedimentary origin of sulfide-bearing banded iron and silica-rich formations. Sharp isotopic transitions across sedimentary/igneous lithological boundaries indicate that primary surficial S-isotope compositions have been preserved despite a complicated metamorphic history. Furthermore, Nuvvuagittuq metasediments recorded coupled variations in (33)S/(32)S, (34)S/(32)S, and (36)S/(32)S that are statistically indistinguishable from those identified several times later in the Archean. The recurrence of the same S-isotope pattern at both ends of the Archean Eon is unexpected, given the complex atmospheric, geological, and biological pathways involved in producing and preserving this fractionation. It implies that, within 0.8 billion years of Earth's formation, a common mechanism for S-MIF production was established in the atmosphere.

Non-Radiometric Dating of the Age of the Earth: Implications From Fossil Coral Evidence

Radioisotope dating has revealed that the age of the Earth is 4.54–4.6 billion years, and these results are widely accepted. However, as with all searches for truth in science, facts should be supported by multiple lines of evidence. Thus, determining the age of the Earth with alternative techniques could serve to strengthen the conclusions that have been reached with radioisotope dating methods. In this paper, a different approach to solving the problem is proposed. As is known from studies of 400 million year old fossil corals, Earth years were 400 days in duration in distant times because the Earth rotated faster than it does today. According to calculations based on the fundamental law of rotational motion dynamics involving the moment of inertia of a body, the radius of the ancient Earth 400 million years ago was 553.379 km less than it is today. This brings us to the impressive conclusion that Earth’s radius grew on average by 1.3834475 mm per year over the past 400 million years. Let us call this the evolutionary Earth growth constant; it does not take into account the effect of lunar tidal friction. If the present day Earth radius of 6371 km is divided by 1.3834475 mm per year, we can estimate the growth time of the Earth from its beginning to the presentthe growth time is 4.6 billion years, which is consistent with the radioisotope data, i.e., 4.6 billion years equals the age of the Earth! This new method for measuring Earth’s age not only confirms outcomes obtained with radiological methods, but it poses new problems and avenues of research for paleogeologists.

Modeling of abiotic ATP synthesis in the context of problems of early biosphere evolution

The pathway of adenosine triphosphate (ATP) synthesis in living organisms consists of two autonomous stages; this must be taken into account during the design and analysis of chemical models of the abiogenesis of this key participant of metabolic processes. The first stage is construction of an adenine heterocycle linked to a ribose-5-phosphate molecule to yield AMP, while the following stage is the attachment of phosphoryl residues to the nucleotide molecule by macroergic phosphoanhydride bonds. Involvement of the same set of precursor molecules in both de novo biosynthesis of AMP and abiogenesis of this nucleotide is a very important issue for the analysis of metabolic pathways. Photochemical matrix systems that convert light energy into macroergic bond energy are functional prototypes of photosynthetic phosphorylation; they are of special interest for the construction of abiotic phosphorylation models. Interaction of substrates with a purely mineral matrix (montmorillonite particles) under UV irradiation resulted in the formation of ATP from ADP and orthophosphate. Micro-and nanostructures that formed upon the interaction of the mineral component (sodium polysilicate) with an abiogenic organic pigment (a flavin conjugate with a random amino acid polymer) exhibited phosphorylating activity as well when irradiated with visible light. The properties of AMP and ATP abiosynthesis models investigated are in good accordance with the current views on the environmental conditions of the ancient Earth; evident structural differences exist between these models and the biosynthetic systems in modern organisms.

Late Holocene soil and vegetational changes in the foothills of the SE Carpathians (Ukraine), based on the study of pedochronocatenas

A study of pedochronocatenas which include soils of archaeological sites is a reliable approach to reconstruct environmental changes since the time of the settlements existence. The studied pedochronocatenas include: 1) soils buried under ancient earth ramparts, 2) soils formed on the surface of these ramparts, and 3) natural undisturbed soils located close to the ramparts. The studied sites are located on the plateau between the Prut and Siret rivers (in the Glyboka district of the Chernivtsi region, South-Eastern part of the Ukrainian Carpathians). At present, this area is covered mainly by Haplic Greyzems and Dystric Cambisols under broad-leaved forests. Pedochronocatenas at two sites have been studied: 1) the Glyboka defensive rampart built during the IX-Xth centuries AD (1100-1000 yr BP, 14 C 1040±190, the Early Slavic time) and 2) the Grushivka rampart built as a defence from the Scythians during the Vth century BC (2500-2400 BP), but also with the new material deposited on the old rampart during the Early Slavic times. According to archaeologists [3–6] the ramparts were built in order to defend those sides of the settlements which were unprotected by natural barriers. Morphological and morphometrical soil analysis, as well as pollen study have been carried out in order to trace pedogenic, vegetational and climatic changes since the time of the rampart’s construction.

Electrochemical CO2 Reduction by Ni-containing Iron Sulfides: How Is CO2 Electrochemically Reduced at Bisulfide-Bearing Deep-sea Hydrothermal Precipitates?

The discovery of deep-sea hydrothermal vents on the late 1970's has led to many hypotheses concerning chemical evolution in the prebiotic ocean and the early evolution of energy metabolism in ancient Earth. Such studies stand on the quest for the bioenergetic evolution to utilize reducing chemicals such as H2 for CO2 reduction and carbon assimilation. In addition to the direct reaction of H2 and CO2, the electrical current passing across a bisulfide-bearing chimney structure has pointed to the possible electrocatalytic CO2 reduction at the cold ocean-vent interface (R. Nakamura, et al. Angew. Chem. Int. Ed. 2010, 49, 7692−7694). To confirm the validity of this hypothesis, here, we examined the energetics of electrocatalytic CO2 reduction by iron sulfide (FeS) deposits at slightly acidic pH. Although FeS deposits inefficiently reduced CO2, the efficiency of the reaction was substantially improved by the substitution of Fe with Ni to form FeNi2S4 (violarite), of which surface was further modified with amine compounds. The potential-dependent activity of CO2 reduction demonstrated that CO2 reduction by H2 in hydrothermal fluids was involved in a strong endergonic electron transfer reaction, suggesting that a naturally occurring proton-motive force (PMF) as high as 200mV would be established across the hydrothermal vent chimney wall. However, in the chimney structures, H2 generation competes with CO2 reduction for electrical current, resulting in rapid consumption of the PMF. Therefore, to maintain the PMF and the electrosynthesis of organic compounds in hydrothermal vent mineral deposits, we propose a homeostatic pH regulation mechanism of FeS deposits, in which elemental hydrogen stored in the hydrothermal mineral deposits is used to balance the consumption of the electrochemical gradient by H2 generation.

Baking Geophytes and Tracking Microfossils: Taphonomic Implications for Earth-Oven and Paleodietary Research

Archaeologically oriented starch-granule and other plant-food microfossil research contribute to human subsistence studies primarily through analysis of residue adhering to plant processing tools. Little is known about whether or how plant-food microfossils may be present in remains of ancient earth ovens and other cooking facilities. Earth ovens with rock heating elements are found worldwide, especially in savannah and fuel-poor regions; they date to about 30,000 and 9,000 years old in the Old and New Worlds, respectively. Earth-oven baking is a cooking technology that effectively increases the availability of food in a given area by affording nutritional access to difficult-to-cook or toxic plant foods that would otherwise be indigestible. It effectively increases a landscape’s capacity to support population growth. Conventional-oven and lab-oven baking experiments assess the potential of ancient earth ovens to yield identifiable microfossils of underground storage organs (USOs) baked therein. During 15 min to 12 h of baking at 135–150 °C, identifiable and degraded USO microfossils accumulated as part of baking residue on cloth coverings, leafy packing materials, the inside of the containers, and on suspended microscope slides. Results of these taphonomic experiments indicate that an abundance of microfossils, including starch granules, phytoliths, raphides, and plant tissue, are emitted from USOs during the baking process. As hypothesized, these microfossils should be mobilized and dispersed in earth ovens per se during baking, primarily via liquid and vapor forms of water. Illuviation and other transformation processes are expected to redeposit baked, yet still identifiable, plant-food microfossils on heating-element rocks.

Study of ancient Earth–Theia collision sheds new light on geologic history

Study of ancient Earth–Theia collision sheds new light on geologic history

Microbial mediated formation of Fe-carbonate minerals under extreme acidic conditions

Discovery of Fe-carbonate precipitation in Rio Tinto, a shallow river with very acidic waters, situated in Huelva, South-western Spain, adds a new dimension to our understanding of carbonate formation. Sediment samples from this low-pH system indicate that carbonates are formed in physico-chemical conditions ranging from acid to neutral pH. Evidence for microbial mediation is observed in secondary electron images (Fig. 1), which reveal rod-shaped bacteria embedded in the surface of siderite nanocrystals. The formation of carbonates in Rio Tinto is related to the microbial reduction of ferric iron coupled to the oxidation of organic compounds. Herein, we demonstrate for the first time, that Acidiphilium sp. PM, an iron-reducing bacterium isolated from Rio Tinto, mediates the precipitation of siderite (FeCO3) under acidic conditions and at a low temperature (30°C). We describe nucleation of siderite on nanoglobules in intimate association with the bacteria cell surface. This study has major implications for understanding carbonate formation on the ancient Earth or extraterrestrial planets.

The Paleobiosphere: a novel device for the in vivo testing of hydrocarbon producing-utilizing microorganisms

The construction and testing of a unique instrument, the Paleobiosphere, which mimics some of the conditions of the ancient earth, is described. The instrument provides an experimental testing system for determining if certain microbes, when provided an adequate environment, can degrade biological materials to produce fuel-like hydrocarbons in a relatively short time frame that become trapped by the shale. The conditions selected for testing included a particulate Montana shale (serving as the "Trap Shale"), plant materials (leaves and stems of three extant species whose origins are in the late Cretaceous), a water-circulating system, sterile air, and a specially designed Carbotrap through which all air was passed as exhaust and volatile were hydrocarbons trapped. The fungus for initial testing was Annulohypoxylon sp., isolated as an endophyte of Citrus aurantifolia. It produces, in solid and liquid media, a series of hydrocarbon-like molecules. Some of these including 1,8-cineole, 2-butanone, propanoic acid, 2-methyl-, methyl ester, benzene (1-methylethyl)-, phenylethyl alcohol, benzophenone and azulene, 1,2,3,5,6,7,8,8a-octahydro-1,4-dimethyl-7-(1-methylethenyl), [1S-(1α,7α,8aβ)]. These were the key signature compounds used in an initial Paleobiosphere test. After 3 weeks, incubation, the volatiles associated with the harvested "Trap Shale" included each of the signature substances as well as other fungal-associated products: some indanes, benzene derivatives, some cyclohexanes, 3-octanone, naphthalenes and others. The fungus thus produced a series of "Trap Shale" products that were representative of each of the major classes of hydrocarbons in diesel fuel (Mycodiesel). Initial tests with the Paleobiosphere offer some evidence for a possible origin of hydrocarbons trapped in bentonite shale. Thus, with modifications, numerous other tests can also be designed for utilization in the Paleobiosphere.

The Earth: its birth and growth

Preface to the second edition Preface to the first edition 1. Heat from within: energy supporting the dynamic Earth 2. At the time of Earth's birth 3. Formation of the layered structure of Earth 4. Time scale of Earth's evolution 5. Plate tectonics evolution 6. Evolution of the mantle 7. Origin of the atmosphere and oceans 8. Isotopes as DNA of nature 9. Earth's magnetism 10. Moon: a looking glass to mirror the ancient Earth 11. The past and future of the evolving Earth References Index.

CHEMICAL BIOMARKERS IN AQUATIC ECOSYSTEMS

By T Bianchi, E Canuel. ( 2011) Princeton University Press. 392 pp. List price US $95.00; Kindle available. ISBN: 978-0691134147. The book Chemical Biomarkers in Aquatic Ecosystems by T. Bianchi and E. Canuel describes organic matter as it relates to globally important processes in biogeochemistry. Chemical biomarkers, or biomarker molecules, are defined here as compounds that characterize certain biotic sources and selectively retain their source information, even after stages of decomposition and diagenesis. Biomarkers, for the most part, are organic molecules and are used to gain insight into many aspects of the modern and ancient Earth system. The information from biomarkers can be applied to a broad range of overlapping studies including areas ranging from fossil fuels, evolution of life on Earth, and microbial chemotaxonomy, to the cycling of carbon, nutrients, and energy. In their book, Bianchi and Canuel demonstrate the utility of organic molecules as tracers of processes occurring in aquatic ecosystems, both modern and ancient, especially where combined with isotopic analysis of …

The Microbial Factor of Travertine Deposition between Yellowstone National Park (YNP), USA and Huanglong Scenic, Sichuan

Yellow Stone National Park (YNP), USA, is well-known as its glorious travertine geomorphology as well as Huanglong National Scenic District in Sichuan, China. But there were some difference between them. The travertine deposition of YNP were formed from geothermal activity, meanwhile Huanglong Scenic District is located in high attitude and cold area and the travertine deposition appeared in the cold water. With the increasing attention to global carbon cycle, origin of life and the life action in the extreme environment, the geothermal travertine formation origin and mechanism were focused by the scientists from different field. The research plan was also a part of “the Mars project”. The reason was that the Mars’s surface environment is similar to that of the ancient Earth. This article reviewed the research results of the microbiology diversity, community structure and distribution, function gene and special microbial carbon metabolism passway in the hot spring of YNP. We also summarized the biological factor in the process of the travertine deposition of YNP. After comparing the research progress on the travertine deposition between YNP and Huanglong Scenic District, we put foreword the further strategy to understand the biological effect on the travertine deposition of Huanglong Scenic District.

Ocean–Atmosphere Interactions in the Emergence of Complexity in Simple Chemical Systems

The prebiotic conversion of simple organic molecules into complex biopolymers necessary for life can only have emerged on a stage set by geophysics. The transition between "prebiotic soup," the diverse mixture of small molecules, and complex, self-replicating organisms requires passing through the bottleneck of fundamental chemistry. In this Account, we examine how water-air interfaces, namely, the surfaces of lakes, oceans, and atmospheric aerosols on ancient Earth, facilitated the emergence of complex structures necessary for life. Aerosols are liquid or solid suspensions in air with a broad, power law size distribution. Collectively, these globally distributed atmospheric particles have an enormous surface area. Organic films at the interface between water and air offer advantages for biomolecular synthesis compared with the bulk and can simultaneously participate in the folding of biopolymers into primitive enclosed structures. We survey the advantages of the water-air interface for prebiotic chemistry in a geophysical context from three points of view. We examine the formation of biopolymers from simple organic precursors and describe the necessity and availability of enclosures. In addition, we provide a statistical mechanical approach to natural selection and emergence of complexity that proposes a link between these molecular mechanisms and macroscopic scales. Very large aerosol populations were ubiquitous on ancient Earth, and the surfaces of lakes, oceans, and atmospheric aerosols would have provided an auspicious environment for the emergence of complex structures necessary for life. These prebiotic reactors would inevitably have incorporated the products of chemistry into their anhydrous, two-dimensional organic films in the three-dimensional fluids of the gaseous atmosphere and the liquid ocean. The untrammeled operation of natural selection on these aerosols provided the likely location where condensation reactions could form biopolymers by elimination of water. The fluctuating exposure of the large, recycling aerosol populations to radiation, pressure, temperature, and humidity over geological time allows complexity to emerge from simple molecular precursors. We propose an approach that connects chemical statistical thermodynamics and the macroscopic world of the planetary ocean and atmosphere.

U–Th–Pb isotope data indicate phanerozoic age for oxidation of the 3.4 Ga Apex Basalt

The occurrence of ferric oxides in Archean rocks has played an important role in discussions on the amount of free oxygen in the atmosphere of the ancient Earth. Recognizing that post-Archean weathering may also produce oxide minerals, drill cores have been used to obtain samples beneath the depth of Phanerozoic weathering. The first core of the Archean Biosphere Drilling Project (ABDP-1) documented hematite as alteration products in 3.4Ga basalts from the Marble Bar area of the Pilbara Craton, NW Australia, and this has been used to infer the presence of an O2-bearing atmosphere in the Archean. It is possible, however, that despite recovery of samples from >100m depth, oxidation of the basalts occurred much younger than the depositional age. In this study, the age of oxidation of the Apex Basalt from the ABDP-1 drill core at Marble Bar is constrained by U–Th–Pb geochronology. Lead and U concentrations of the basalts from the ABDP-1 drill core vary greatly, between <1–58ppm and 0.08–1.04ppm, respectively, whereas Th contents are more restricted (0.24–0.71ppm). 206Pb/204Pb ratios are non-radiogenic and vary from 12.44 to 14.69. The linear array in terms of 206Pb/204Pb–207Pb/204Pb variations does not reflect an age but reflects two-component mixing between a non-radiogenic “ore lead” end member and a radiogenic “basalt lead” end member. The samples do not form isochrons on 238U/204Pb–206Pb/204Pb, 235U/204Pb–207Pb/204Pb, or 232Th/204Pb–208Pb/204Pb diagrams, indicating post-formation U and Pb addition. Comparison of measured U/Th ratios with “model” U/Th ratios calculated based on 208Pb/204Pb–206Pb/204Pb variations indicates that U enrichment most likely occurred in the last 200Ma. The degree of U enrichment in the samples is correlated with Fe(III)/FeTotal ratios, indicating that U addition and oxidation were related, most likely reflecting penetration of oxygenated surface waters in the Phanerozoic along bedding planes and shear zones. These results, therefore, indicate that oxidation of the Apex Basalt did not occur in the Archean, and therefore cannot be used to infer an oxygenated atmosphere at that time.

The cob building technique. Past, present and future

Cob, an ancient earth building technique has given rise to hundreds of thousand buildings across Europe for centuries. It has a very distinct appearance of substantial organic walls punctuated with small apertures whose windows and doors are set back to create deep reveals. Traditionally protected by thatched roofs, these vernacular buildings make an important contribution to local identity. Cob buildings still survive and continue to be occupied in many European countries including France, Italy, Germany, Belgium, Czech Republic and England (1). Following a description of the cob technique, this paper will present a brief overview of the history of cob in Devon, a county in South West England. Recent English cob buildings will be introduced with a discussion of the potential of this earth building technique for future architecture.

The Origins Divide: Reconciling Views on How Life Began

F our and a half billion years ago, the planet Earth coalesced out of the gas and dust left over from the formation of the sun. For the next several hundred million years, the young planet was bombarded by comets and meteorites, volcanic eruptions raged across its surface, and its heat boiled the nascent oceans. But within about a billion years—and perhaps much earlier—life had arisen. How nonliving chemicals transformed into living molecules is one of the biggest mysteries in science, and we might never know for sure how it happened. Deep divides in opinion are found in almost all areas of origin-of-life research. Did life begin in extreme heat or relative cold? Were its essential molecules synthesized in the prebiotic ocean, at the mouths of churning deep-sea vents, or did they rain down from space? Did the first life-form get its energy from the sun or from the chemical energy of minerals? Were inherited genetic molecules essential to the first life-form, or could life simply have been a chain of chemical reactions taking place on a rock? “If we’re going to make any progress, we really have to be critically life couldn’t arise out of nothing, then where did it come from? A few years later, Darwin speculated about chemical reactions in a “warm little pond,” and Alexander Oparin and J. B. S. Haldane independently took that idea a step further by proposing that life began in a primordial ocean of organic molecules. Origin-of-life research didn’t get its experimental start, however, until the famed chemical synthesis experiments of Stanley Miller and Harold Urey, of the University of Chicago, were published in 1953. By sending an electrical current through a mixture of water, methane, ammonia, and hydrogen, they simulated what might have happened when lightning struck the oceans and atmosphere of ancient Earth. What they got—a mixture of key amino acids and other organic molecules—profoundly changed views of the origin of life. The origin of biology was now experimentally approachable. Other groups soon conducted similar experiments, and in the following years, researchers managed to synthesize not only additional amino acids but also other essential biomolecules, including sugars, metabolic acids, and lipids. honest about what we don’t know,” says geochemist George Cody, of the Carnegie Institution for Science in Washington, DC. “And that’s just about everything.” The questions surrounding life’s origins are indeed vast and, for the most part, unanswered. A comprehensive explanation of the origin of life will require pinning down the beginnings of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), of proteins and lipid membranes, of genetic coding and metabolic machinery. In modern life, all of these molecules and processes are so intertwined that it’s difficult to imagine how any of them could have arisen without the others already in place. Chicken-andegg problems abound. But new technologies, hypotheses, and experiments are constantly surfacing, and each step reveals a bit more of the way the inanimate chemistry of Earth’s beginnings may have morphed into the remarkable variety of life we see today.

Electrical Current Generation across a Black Smoker Chimney

In environments isolated from solar radiation, diverse microbial populations and ecosystems are sustained by the chemical energy supplied from Earth!s interior. The most outstanding example is a deep-sea hydrothermal vent, which discharges enormous amounts of reductive energy in the form of reduced sulfur compounds, H2, CH4, and reduced metals during magma degassing and hydrothermal reactions with hot rocks. 3] Hydrothermal vent chimneys are generated by mineralization in the mixing zone between hot, reduced hydrothermal fluid and cold, oxygenated seawater and provide an ideal habitat for chemolithotrophic microbial communities. As the chimney structures serve as an interface between the Earth!s reductive interior and oxidative exterior, sustained microbial redox metabolism is very feasible. Simultaneously, the energy potential mediated by the chimney structure leads to many hypotheses concerning chemical evolution in the prebiotic ocean and the early evolution of energy metabolisms and cellular functions in the ancient Earth. Black smokers are a type of hydrothermal vent with sulfide-rich emissions that precipitate to form sulfide mineral chimneys consisting mainly of chalcopyrite (CuFeS2) and pyrite (FeS2). The mineralogical and structural characteristics of black smoker chimneys have been extensively studied; however, electrical conduction and electrocatalysis of black smoker chimneys have never been examined. Although bulk crystals of CuFeS2 and FeS2 are typically considered poor conductors, it is predicted that a chimney structure composed of nanoand microsized crystalline particles would have quite a large surface area with the potential of mediating the efficient electron transport. Herein we therefore examine the electrochemical characteristics of the black smoker chimney and seek to estimate the redox potential between the hydrothermal fluid conduit and ambient seawater across the chimney wall. For the analysis, a black smoker sulfide chimney obtained from the Mariner hydrothermal field in the southern Lau Basin was characterized (Figure 1). The observed electrical conduction potential points to a possible new type of energy transport from hydrothermal fluid to seawater by electrical current generation in the sulfide chimney wall.