Keyron Hickman-LewisNatural History Museum, London · Department of Earth Sciences
Keyron Hickman-Lewis
Ph.D. (Orléans and Bologna); Master of Earth Sciences (M.EarthSci) Oxon.
About
46
Publications
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Introduction
Earth Scientist interested in the early history of life. Particular interests are in Archaean microbial palaeontology, biogeochemistry, early surface environments and ecosystems, the search for life on Mars, and Mars Sample Return. I am interested in the development and application of novel techniques and approaches to criteria for determining the biogenicity and metabolic affinities of Precambrian fossils and assimilating these findings into ecosystem and "biome" models.
Additional affiliations
November 2016 - October 2019
January 2016 - October 2016
June 2015 - August 2015
Oxford University Museum of Natural History
Position
- Research Assistant (Internship)
Description
- Curation of the "Prof Stephen Moorbath Greenland Rock Collection", consisting of meta-igneous and meta-sedimentary rocks from Isua (3.85Ga) and other >3.70Ga West Greenland units.
Education
November 2016 - October 2019
November 2016 - October 2019
October 2011 - July 2015
Publications
Publications (46)
A wide spectrum of tomographic techniques now exists for studying palaeontological specimens, but the suitability of these methods for assessing Earth's oldest prokaryotic life has not been comprehensively investigated. We evaluated the ability of X-ray computed tomography – specifically X-ray microtomography – to reveal the morphology and petrolog...
Palaeoarchaean cherts preserve the most ancient direct traces of life, but this palaeobiological testament is rarely assimilated into ecosystem or biome models. Trace and rare earth element plus yttrium (REE+Y) compositions reliably decode the palaeodepositional settings of these cherts, and thus constrain the environments within which early microb...
Modern biological dependency on trace elements is proposed to be a consequence of their enrichment in the habitats of early life together with Earth's evolving physicochemical conditions; the resulting metallic biological complement is termed the metallome. Herein, we detail a protocol for describing metallomes in deep time, with applications to th...
Limited taxonomic classification is possible for Archaean microbial mats and this is a fundamental limitation in constraining early ecosystems. Applying Fourier transform infrared spectroscopy (FTIR), a powerful tool for identifying vibrational motions attributable to specific functional groups, we characterized fossilized biopolymers in 3.5-3.3 Ga...
Powdered rocks are commonly present at the surface of extraterrestrial bodies and are widely analysed by in situ space probes. Moreover, a number of rovers exploring the surface of Mars are equipped with drills enabling them to access unaltered material and collect samples. During drilling operations, a cone of powder made of the drilled materials...
In this work, we address the difficulty of reliably identifying traces of life on Mars. Several independent lines of evidence are required to build a compelling body of proof. In particular, we underline the importance of correctly interpreting the geological and mineralogical context of the sites to be explored for the presence of biosignatures. W...
Observations from orbital spacecraft have shown that Jezero crater, Mars, contains a prominent fan-shaped body of sedimentary rock deposited at its western margin. The Perseverance rover landed in Jezero crater in February 2021. We analyze images taken by the rover in the three months after landing. The fan has outcrop faces that were invisible fro...
The Kaapvaal and Zimbabwe cratons host some of the earliest evidence for life. When compared to the contemporaneous East Pilbara craton, cherts and other metasedimentary horizons in southern Africa preserve traces of life with far greater morphological and geochemical fidelity. In spite of this, most fossiliferous horizons of southern Africa have r...
The practical limitations inherent to human and robotic planetary exploration necessitate the development of specific protocols and methods. This non-standard approach requires testing and validation phases in order to optimize instrumental setups and improve data interpretation; this can occur prior to, during, or even after a mission. Flight inst...
Life is the outcome of a complex network of chemical reactions and molecular interactions that emerged on Earth once primitive chemical automata could self-assemble in such a way that enabled them to self-reproduce and evolve. Yet exactly how, where and when life first appeared on our planet remains unknown. In this chapter, we review the various l...
Precambrian cellular remains frequently have simple morphologies, micrometric dimensions and are poorly preserved, imposing severe analytical and interpretational challenges, especially for irrefutable attestations of biogenicity. The 1.88 Ga Gunflint biota is a Precambrian microfossil assemblage with different types and qualities of preservation a...
The icy moons of the outer Solar System harbor potentially habitable environments for life, however, compared to the terrestrial biosphere, these environments are characterized by extremes in temperature, pressure, pH, and other physico-chemical conditions. Therefore, the search for life on these icy worlds is anchored on the study of terrestrial e...
Five bacterial (facultatively) anaerobic strains, namely Buttiauxella sp. MASE-IM-9, Clostridium sp. MASE-IM-4, Halanaerobium sp. MASE-BB-1, Trichococcus sp. MASE-IM-5, and Yersinia intermedia MASE-LG-1 isolated from different extreme natural environments were subjected to Mars relevant environmental stress factors in the laboratory under controlle...
We propose an innovative method based on photography and image processing of interdisciplinary relevance, permitting the uncomplicated and inexpensive evaluation of material properties. This method—CaliPhoto—consists of using a dedicated colour plate with a specific design, placed in the field of view of a photograph of the material to be character...
The ExoMars 2020 mission will characterise a Martian locality with potential former habitability – Oxia Planum – and attempt to identify preserved morphological and chemical biosignatures. The payload will include a drill retrieving cores from the subsurface (up to 2m depth), which will be imaged at high resolution by two instruments: the Panoramic...
Morphologically diverse organo-sedimentary structures (including microbial mats and stromatolites) provide a palaeobiological record through more than three billion years of Earth history. Since understanding much of the Archaean fossil record is contingent upon proving the biogenicity of such structures, mechanistic interpretations of well-preserv...
Electron paramagnetic resonance (EPR) analysis of carbonaceous, volcanic, tidal sediments from the 3.33 Ga-old Josefsdal Chert (Kromberg Formation, Barberton Greenstone Belt), documents the presence of two types of insoluble organic matter (IOM): (1) IOM similar to that previously found in Archean cherts from numerous other sedimentary rocks in the...
The Dallol volcano and its associated hydrothermal field are located in a remote area of the northern Danakil Depression in Ethiopia, a region only recently appraised after decades of inaccessibility due to severe political instability and the absence of infrastructure. The region is notable for hosting environments at the very edge of natural phys...
Life on the early Earth inhabited a planet whose environment was vastly different from the Earth of today. An anaerobic and hot early Earth was the birthplace of the first living cells but wide-spread small-scale physico-chemical diversity provided opportunities for a variety of specialists: alkalophiles, acidophiles, halophiles etc. The earliest r...
There is much convincing evidence for early life in the Barberton greenstone belt (3.47-3.22 Ga), portraying a diverse Paleoarchean biosphere that occupied both marine and terrestrial habitats. This stands testament to the already widespread distribution and diversity of life on the early Earth. We here present an up-to-date review of fifty years o...
Raman spectroscopy is a molecule-specific technique allowing the investigation of the chemical structure of organic and inorganic geological materials. Being a nobiostructures from the Barberton greenstone belt of South An-invasive analytical procedure, Raman spectroscopy is ideally suited to palaeontology. Raman spectroscopy is herein applied to t...
The particle size, shape, surface texture and composition of aeolian and fluvial sedimentary samples were analyzed and compared using optical microscope-based automatized image analysis, in order to suggest indicators that could discriminate these two modes of transport on Mars. The principal goal is to assess if such indicators – established on Ea...
Critical to the origin of life are the ingredients of life, of course, but also the physical and chemical conditions in which prebiotic chemical reactions can take place. These factors place constraints on the types of Hadean environment in which life could have emerged. Many locations, ranging from hydrothermal vents and pumice rafts, through volc...
On a volcanic and anaerobic planet characterized by abundant hydrothermal activity, physicochemical gradients and disequilibria at the local scale would have been fundamental for the emergence of life on Earth. Unfortunately, the early rock record pertaining to this existential process no longer exists, and, while chemists attempt to recreate life...
On a volcanic and anaerobic planet characterized by abundant hydrothermal activity, physicochemical gradients and disequilibria at the local scale would have been fundamental for the emergence of life on Earth. Unfortunately, the early rock record pertaining to this existential process no longer exists, and, while chemists attempt to recreate life...
In this study, we attempt to illustrate the competition that constitutes the main challenge of astrobiology, namely the competition between the probability of extraterrestrial life and its detectability. To illustrate this fact, we propose a simple statistical approach based on our knowledge of the Universe and the Milky Way, the Solar System, and...
This review introduces its readers to a ‘stochastic approach’ to origins of life research, from the viewpoints of both prebiotic chemistry and geology. The idea of a “primordial soup” has been subject to extensive criticism from thermodynamic, biochemical and geochemical perspectives, yet recent advancements have made clearer the plausibility of th...
This paper outlines the suite of advanced multi-scalar techniques currently available in the toolkit of the modern Proterozoic palaeobiologist. These include non-intrusive and non-destructive optical, laser and X-ray techniques, plus more destructive ion beam and electron beam methods. Together, these provide morphological, mineralogical and bioche...
Hydrothermal black chert veins intruding the 3.46 Ga Apex Basalt contain some of Earth’s oldest microfossil-like objects, whose biogenicity has been questioned. Whilst these black chert veins have been studied in great detail, relatively little is known about the stratiform, seafloor, sedimentary cherts that are conformably interbedded with volcani...
Projects
Project (1)
The 3.46 Ga Apex chert is best known for its containing filamentous objects now recognised as artefact pseudofossils, located within a chert dyke of hydrothermal genesis. We have studied the overlying and intercalated "stratiform Apex chert", reflecting a more quiescent volcaniclastic-sedimentary environment, within which we have identified a suite of carbonaceous microstructures resembling microbially induced sedimentary structures (MISS). Morphology in two and three dimensions, and detailed in situ geochemistry indicate that these structures pass many of the criteria for biogenicity.
Herein are contained our efforts to fully analyse these curious phenomena, and elucidate what they may tell us of hydrothermally influenced biospheres in the Early Archaean.
