Christopher D K Herd

• Ph.D.
• Professor at University of Alberta

The Perseverance rover has sampled mm‐size lithic fragments containing olivine likely from at least two source regions from the surface of an inactive megaripple surface, and fine‐grained material from the surface and to a depth of ∼4–6 cm. Some of the mm‐size grains lack a coherent diffraction pattern measured by PIXL, consistent with the presence...

The Perseverance rover has collected seven oriented samples of sedimentary rocks, all likely older than the oldest signs of widespread life on Earth, at the exposed base of the western fan in Jezero crater, Mars. The samples include a sulfate‐ and clay‐bearing mudstone and sandstone, a fluvial sandstone from a stratigraphically low position at the...

We analyzed the methanol extracts of six pristine specimens of the Tagish Lake meteorite (TL1, TL4, TL5A, TL6, TL7, and TL10a) and heated and unheated samples of Allende using high‐performance liquid chromatography coupled with high‐resolution, accurate mass–mass spectrometry (HPLC‐HRAM‐MS). All samples contained ppm levels of sulfate and methyl su...

The Golden (British Columbia, Canada) meteorite fall occurred on October 4, 2021 at 0534 UT with the first recovered fragment (1.3 kg) landing on an occupied bed. The associated fireball was recorded by numerous cameras permitting reconstruction of its trajectory and orbit. The fireball entered the atmosphere at a 54° angle from the horizontal at a...

In situ geologic context mapping based on rover and helicopter observations provides documentation of a nearly continuous record of geology and exposed surface structure over a 120 m‐wide corridor along the traverse of the Mars 2020/Perseverance rover. The results record the geologic context of Mars 2020 campaign sites and sample sites, including t...

The first samples collected by the Mars 2020 mission represent units exposed on the Jezero Crater floor, from the potentially oldest Séítah formation outcrops to the potentially youngest rocks of the heavily cratered Máaz formation. Surface investigations reveal landscape‐to‐microscopic textural, mineralogical, and geochemical evidence for igneous...

The frequency of crater-producing asteroid impacts on Earth is not known. Of the predicted Holocene asteroid impact craters of <200 m diameter, only ~30% have been located. Until now there has been no way to distinguish them from “normal” terrestrial structures unless pieces of iron meteorites were found nearby. We show that the reflective properti...

The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater’s sedimentary delta, finding the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which acc...

The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigate the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the P...

The insoluble organic material (IOM) in primitive chondritic meteorites is very enriched in D (up to δD≈3500 ‰ in bulk). Based largely on a series of electron paramagnetic resonance (EPR) studies of IOM from three meteorites (Orgueil, Murchison and Tagish Lake), it has been suggested that these enrichments are the result of exchange with H2D⁺ in th...

The world's meteorite collections contain a very rich picture of what the early Solar System would have been made of, however the lack of spatial context with respect to their parent population for these samples is an issue. The asteroid population is equally as rich in surface mineralogies, and mapping these two populations (meteorites and asteroi...

The meteorite collections contain a very rich picture of what the early Solar System would have been made of, however the lack of spatial context with respect to their parent population for these samples is an issue. The asteroid population is equally as rich in surface mineralogies, and mapping these two populations (meteorites and asteroids) toge...

Just as geological samples from Earth record the natural history of our planet, astromaterials hold the natural history of our solar system and beyond. Astromaterials acquisition and curation practices have direct consequences on the contamination levels of astromaterials and hence the types of questions that can be answered about our solar system...

Effects of aqueous alteration on primordial noble gas carriers were investigated by analyzing noble gases and determining presolar SiC abundances in insoluble organic matter (IOM) from four Tagish Lake meteorite (C2‐ung.) samples that experienced different degrees of aqueous alteration. The samples contained a mixture of primordial noble gases from...

Hyperspectral imaging can be used to rapidly identify and map the spatial distributions of many minerals. Here, hyperspectral mapping in three wavelength regions (visible and near‐infrared, shortwave infrared, and thermal infrared) was applied to drill cores (ST001, ST002, and ST003) penetrating a continuous sequence of crater‐fill breccias from th...

Hypervelocity bolide impacts deliver vast amounts of energy to the Earth's near surface. This crustal process almost universally includes sedimentary target rocks; however, their response to impact is poorly understood, in part because of complexities due to layering, pore space and the presence of volatiles that are difficult to model. The respons...

Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Strategies for the collection of such samples have ranged from “grab and go” acquisition from the surface, to dust collection in the atmosphere, to scientific selection by geologically capable rovers. As comprehension of the comple...

Executive Summary Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team ( iMOST ). The purpose of the team is to re‐evaluate and update the...

This report requested by the International Mars Exploration Working Group (IMEWG). Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (i...

Executive Summary: Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (iMOST). The purpose of the team is to re-evaluate and update the...

The Steen River impact structure (SRIS) formed in mixed target rocks, with Devonian carbonates, shales, and evaporites overlying granitic basement rocks of the Canadian Shield. A detailed study of impact melt phases within a continuous sequence of polymict impact breccia, as intersected by drill core, evaluated the relationship of impact melt to th...

Until 2016 only 38 Italian meteorites have been classified and published on the Meteoritical Bulletin Database. Among these, only 4 were irons. We here report the results of the analyses performed on two iron meteorites recovered in Italy. The first one, Castiglione del Lago, weighing 667g, was recovered in 1970. The textural features observed by m...

We apply an array of in situ analytical techniques, including electron and Raman microscopy, electron and ion probe microanalysis, and laser ablation mass spectrometry to the Tissint martian meteorite in order to find and elucidate a geochemical signature characteristic of low-temperature alteration at or near the martian surface. Tissint contains...

Our goal is to determine the optimal T range for large-scale curation and handling of cometary material, using an IDP analogue and a sub-zero T glove box.

Here, we report a previously unrecognized impactite from the Steen River impact structure in Alberta, Canada, which was intersected by continuous diamond drill core into the allochthonous proximal deposits of this buried 25-km-diameter complex crater. A suite of high-temperature minerals defines the matrix, formed by grain growth in a solid state b...

Tissint is an olivine-phyric shergottite from an incompatible element depleted Martian mantle source. Oxythermobarometry applied to Tissint mineral phases demonstrates that the Tissint magma underwent an increase in oxygen fugacity, from ~3.5 log units below the quarz-fayalite-magnetite (QFM) buffer during the early stages of crystallization, to QF...

With the advent of exoplanetary astronomy and the ongoing discovery of terrestrial-type planets around other stars, our own solar system becomes a key testing ground for ideas about what factors control planetary evolution. In particular, what allows a planet to be both within a potentially habitable zone and sustain habitability over long geologic...

The curation and handling of volatile-bearing astromaterials is of prime importance in current and future plans for sample return missions to targets containing organic compounds, ices, or other volatile components. We report on the specific curation constraints required for the preservation of the Tagish Lake meteorite, a C2 ungrouped chondrite th...

Meteoritical Bulletin 102 contains 3141 meteorites including 12 falls (Boumdeid (2003), Boumdeid (2011), Braunschweig, Chelyabinsk, Dongyang, Draveil, Heyetang, Indian Butte, Katol, Ladkee, Ouadangou, Xining), with 2611 ordinary chondrites, 264 HED achondrites, 124 carbonaceous chondrites, 30 ureilites, 20 Martian meteorites, 16 primitive achondrit...

Meteoritical Bulletin 101 contains 2639 meteorites accepted by the Nomenclature Committee in 2012, including 1 fall (Battle Mountain), with 2308 ordinary chondrites, 156 carbonaceous chondrites, 63 HED achondrites, 17 relict meteorites, 16 Rumuruti chondrites, 15 enstatite chondrites, 15 ureilites, 10 iron meteorites, 9 lunar meteorites, 9 primitiv...

The Whitecourt meteorite impact crater, Alberta, Canada is a rare example of a well-preserved small impact structure, with which thousands of meteorite fragments are associated. As such, this crater represents a unique opportunity to investigate the effect of a low-energy impact event on an impacting iron bolide. Excellent documentation of meteorit...

Four pristine specimens of the Tagish Lake C2 chondrite meteorite were previously determined through mineralogy, petrology, and organic chemistry to have been affected by aqueous alteration in the order (from least to most altered) TL5b ; Blinova et al. ). Here, we report the whole‐rock data for a total of 65 elements for the same four Tagish Lake...

High-precision results are obtained for bulk density, grain density, and porosity of frozen pristine fragments of the Tagish Lake meteorite.

Microimaging VSWIR spectroscopy coupled with microimaging would bring new petrologic capabilities to the exploration of planetary surfaces.

Impact-induced melting of different target compositions leads to predictable melt mineralogies detected on the surface in many different locations.

Elemental ratios in the noble gas component Q might be altered during aqueous alteration. We use IOM in clasts of Tagish Lake to characterize such effects.

We present redox estimates and the preliminary results of petrologic experiments on the Tissint meteorite, and discuss their implications for martian magmatism.

We report here the discovery of a new type of martian meteorite, NWA 8159 augite basalt, that has characteristics distinct from other martian meteorite types.

A new Mars basalt / Defies being classified / Nakhlite related?

The C2 ungrouped Tagish Lake meteorite preserves a range of lithologies, reflecting variable degrees of parent-body aqueous alteration. Here, we report on soluble organic compounds, including aliphatic and aromatic hydrocarbons, monocarboxylic acids, and amino acids, found within specimens representative of the range of aqueous alteration. We find...

Four samples (5b, 11h, 11i, and 11v) from the pristine collection of the Tagish Lake meteorite, an ungrouped C2 chondrite, were studied to characterize and understand its alteration history using ,, and . We determined that samples 11h and 11i have a relatively smaller proportion of amorphous silicate material than sample 5b, which experienced low-...

Spatially resolved argon isotope measurements have been performed on neutron-irradiated samples of NW Africa (NWA) 4797. Shock heating of NWA 4797 completely melted and vesiculated precursor igneous plagioclase, which cooled to an assemblage of plagioclase crystals with interstitial glasses of variable composition (Ca/K ratios). Using a focused ult...

The precise chronology of geological events on Mars is hampered by the lack of absolute ages for the Martian timescale, and the significant uncertainties that result from the extrapolation of the lunar timescale to Mars (Hartmann and Neukum, 2001). Martian meteorites represent the only samples of Mars currently available. Attempts to identify sourc...

Zoned pyroxenes in unbrecciated eucrites NWA 7035 and NWA 7193 allow tracing of HED parent magmatic history. Results are consistent with noncogenetic origin of eucrites.

Survey of Tissint oxide compositions and initial results of oxy-thermobarometry. Results are similar to other olivine-phyric shergottites and may indicate oxidization during closed system crystallization. Experiments to follow.

The high degree of preservation of the Whitecourt Meteorite Impact Crater provides insights into low-energy terrestrial impacts. At the time of this impact, small amorphous carbon spherules may have been generated through a fast pyrolytic reaction.

We describe the cryogenic curation facility at the University of Alberta, and provide an update on results of baseline contamination studies, as well as the challenges of working in the cold.

A review of knowledge about C2 ungrouped Tagish Lake is provided, with a view towards future opportunities in the study of this unique meteorite.

We describe the most magmatically evolved depleted shergottite yet discovered. It is the first known specimen containing maskelynite phenocrysts but apparently lacks phosphates.

To improve the understanding of the 3D nature of nanoglobules, and ultimately better constrain the processes by which they formed, we apply focused ion beam tomography to in situ characterization of nanoglobules from the Tagish Lake meteorite.

We present the new IIAB iron meteorite from High Atlas mountains in Morocco that we submitted under the name Agoudal.

of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Knowledge of Martian igneous and mantle compositions is crucial for understanding Mars' mantle evolution, including early differentiation, mantle convection, and the chemical alteration at the surface. Primitive magmas provide the most direct information about their mantle source regions, but most Martian meteorites either contain cumulate olivine...

Some mineralogical and bulk compositional features of this unique achondrite match known data for Mercury. Could this be a Hermean meteorite?

Whitecourt has a typical IIIAB composition with distorted textures, and porous carbon spherules discovered at the crater site may relate to the impact event.

We are developing FIB-based methods for tomographic analysis at the 50-nm or smaller scale, to improve our understanding of matrix mineralogy.

Abundant impact melt in the Tissint meteorite make it important for understanding remotely sensed data of Mars. We compare lab data and remote observations.

Eucrite pyroxenes from four meteorites with matching oxygen isotopes are inconsistent with cogenesis by existing petrogenetic models, implying multiple sources.

We document two American IAB irons, both of which have anomalous features.

We provide an actual bulk SiO_2 analysis of the Tissint meteorite, along with redox estimates, and then compare Tissint to other shergottites.

Shock metamorphic mineralogy and melt features of the highly differentiated Los Angeles and the more primitive olivine-phyric Tissint meteorites are compared.

Here, we present the results of a multitechnique study of the bulk properties of insoluble organic material (IOM) from the Tagish Lake meteorite, including four lithologies that have undergone different degrees of aqueous alteration. The IOM C contents of all four lithologies are very uniform and comprise about half the bulk C and N contents of the...

The mineralogy, petrology, and geochemistry of an igneous-textured clast in the Peace River L6 chondrite meteorite was examined to determine the roles of nebular processes, accretion, and parent-body metamorphism in its origin. The centimetre-scale clast is grey and fine grained and is in sharp contact with the host chondrite. Two sub-millimetre ve...

Tissint (Morocco) is the fifth martian meteorite collected after it was witnessed falling to Earth. Our integrated mineralogical, petrological, and geochemical study shows that it is a depleted picritic shergottite similar to EETA79001A. Highly magnesian olivine and abundant glass containing martian atmosphere are present in Tissint. Refractory tra...

Results of the application of oxybarometry to martian basalts (shergottite meteorites) are reviewed. Variations in shergottite oxygen fugacity constrain the range of redox states of martian mantle sources.

Northwest Africa 7257 is a medium grained enriched mafic intersertal shergottite with among the highest rare earth element abundances found so far for such Martian specimens.

Northwest Africa (NWA) 4797 is an ultramafic Martian meteorite composed of olivine (40.3 vol%), pigeonite (22.2%), augite (11.9%), plagioclase (9.1%), vesicles (1.6%), and a shock vein (10.3%). Minor phases include chromite (3.4%), merrillite (0.8%), and magmatic inclusions (0.4%). Olivine and pyroxene compositions range from Fo66-72,En58-74Fs19-28...

Application of the Gaussian illumination ion probe method to baddeleyite in Zagami yields a U-Pb age (182 ± 7 Ma) as precise as conventional mineral separation ID-TIMS methods.

The study of Martian meteorites provides insights into geologic processes not amenable to investigation by landed or orbiting missions, as well as best practices of Mars sample curation, handling, and analysis.

A new facility for handling and curiation of meteorites within a sub-zero environment under an Ar atmosphere has been established. Baseline contaminants within the glovebox containing the astromaterials will be described.

The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquid chromatography with fluorescence detection and time-of-flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. Large l-enantiomeric exces...

Constraining the Birthplace of Asteroids Many primitive meteorites originating from the asteroid belt once contained abundant water that is now stored as OH in hydrated minerals. Alexander et al. (p. 721 , published online 12 July) estimated the hydrogen isotopic compositions in 86 samples of primitive meteorites that fell in Antarctica and compare...

The source and nature of carbon on Mars have been a subject of intense speculation. We report the results of confocal Raman imaging spectroscopy on 11 martian meteorites, spanning about 4.2 billion years of martian history. Ten of the meteorites contain abiotic macromolecular carbon (MMC) phases detected in association with small oxide grains inclu...

The new martian meteorite NWA 6234 is an olivine-phyric shergottite and may have special significance. It appears to represent a magma composition and new group of shergottites that is neither depleted nor enriched in incompatible trace elements.

The D/H ratios of water in CCs, Ocs, and Rs are inconsistent with models in which chondritic water and/or chondrites formed in the outer solar system.

We present Mn-Cr data for a large carbonate grain found in pristine Tagish Lake meteorite. These data give us insights into the timing of alteration on the Tagish Lake parent body.

Whole-rock oxygen isotope compositions of four Tagish Lake specimens define a mass fractionation trend with a greater range in variation than any other carbonaceous chondrite. The range is consistent with varying degrees of aqueous alteration.

Two more shergottites found in Northwest Africa emphasize the growing diversity among igneous rocks from Mars.

The first witnessed martian meteorite fall in 49 years is a primitive olivine-phyric shergottite.

The ~382kg of sample returned from the lunar surface during the Apollo missions ranged from samples of gram to kilogram masses. However, any sample return mission from the martian surface will bring back small samples. Learning to get the most of each sample, while keeping enough material for future explorations, will require strategic planning and...

Laboratory studies of meteorites and robotic exploration of Mars reveal scant atmosphere, no evidence of plate tectonics, past evidence for abundant water, and a protracted igneous evolution. Despite indirect hints, direct evidence of a martian origin came with the discovery of trapped atmospheric gases in one meteorite. Since then, the study of ma...