Frank Brenker

Goethe-Universität Frankfurt am Main

Apatite is present as an accessory phase in many meteorites and is often formed as a secondary product of aqueous alteration. Its propensity to incorporate rare earth elements (REE) results in apatite usually being the main REE‐bearing phase in hydrously altered meteorites. Asteroid Ryugu is thought to have experienced pervasive aqueous alteration...

The CB (Bencubbin‐like) metal‐rich carbonaceous chondrites are subdivided into the CB a and CB b subgroups. The CB a chondrites are composed predominantly of ~cm‐sized skeletal olivine chondrules and unzoned Fe,Ni‐metal ± troilite nodules. The CB b chondrites are finer grained than the CB a s and consist of chemically zoned and unzoned Fe,Ni‐metal...

A fundamental parameter-based quantification scheme for confocal XRF was applied to sub-micron synchrotron radiation X-ray fluorescence (SR-XRF) data obtained at the beamline P06 of the Deutsches Elektronen-Synchrotron (DESY, Hamburg, Germany) from two sections C0033-01 and C0033-04 that were wet cut from rock fragment C0033 collected from Cb-type...

Enriched shergottites contain interstitial Si‐rich mesostasis; however, it is unclear whether such mesostasis is formed by impact or magmatic processes. We use laser ablation multicollector inductively coupled plasma mass spectrometry U–Pb measurements of minerals within the interstitial Si‐rich mesostasis and of merrillite within the coarse‐graine...

Millimetre-sized primordial rock fragments originating from asteroid Ryugu were investigated using high energy X-ray fluorescence spectroscopy, providing 2D and 3D elemental distribution and quantitative composition information on the microscopic level. Samples were collected in two phases from two sites on asteroid Ryugu and safely returned to Ear...

The internal structure and dynamics of Earth have been shaped by the 660 km boundary between the mantle transition zone and lower mantle. However, due to the paucity of natural samples from this depth, the nature of this boundary—its composition and volatile fluxes across it—remain debated. Here we analyse the mineral inclusions in a rare type IaB...

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed seventeen Ryugu samples measuring 1-8 mm. CO2-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that forme...

Carbon aggregates from two differently shocked ureilites were analyzed to gain insight into the shock transformation of graphite to diamond in ureilites, which happened when the ureilite parent body (UPB) was most likely destroyed by massive impact events. We present data for carbon aggregates from the highly shocked (U-S6) Northwest Africa (NWA) 6...

The Committee on Space Research (COSPAR) Sample Safety Assessment Framework (SSAF) has been developed by a COSPAR appointed Working Group. The objective of the sample safety assessment would be to evaluate whether samples returned from Mars could be harmful for Earth's systems (e.g., environment, bio-sphere, geochemical cycles). During the Working...

Natural diamonds and their inclusions provide unique glimpses of mantle processes from as deep as ~800 km and dating back to 3.5 G.y. Once formed, diamonds are commonly interpreted to travel upward, either slowly within mantle upwellings or rapidly within explosive, carbonate-rich magmas erupting at the surface. Although global tectonics induce sub...

We performed an experiment under long-term microgravity conditions aboard the International Space Station (ISS) to obtain information on the energetics and experimental constraints required for the formation of chondrules in the solar nebula by ’nebular lightning’. As a simplified model system, we exposed porous forsterite (Mg2SiO4) dust particles...

In order to gain further insights into early solar system aggregation processes, we carried out an experiment on board the International Space Station, which allowed us to study the behavior of dust particles exposed to electric arc discharges under long‐term microgravity. The experiment led to the formation of robust, elongated, fluffy aggregates,...

Reliable identification of chondrules, calcium‐aluminum‐rich inclusions (CAIs), carbonate grains, and Ca‐phosphate grains at depth within untouched, unprepared chondritic samples by a nondestructive analytical method, such as synchrotron X‐ray fluorescence (SXRF) computed tomography (CT), is an essential first step before intrusive analytical and s...

The trace element content and distribution - including rare Earth elements (REEs) - measured in mm-sized asteroidal samples returned by JAXA's Hayabusa2 mission are important chemical parameters to decipher asteroid Ryugu's chronology of formation linked to early Solar System processes. In order to identify and analyze ancient Solar Nebula componen...

Context. Particle aggregation in the solar nebula played a major role in the framework of planet formation; for example, primitive meteorites and their components formed by different aggregation processes. These processes are still not completely understood. Aims. Electrostatic forces probably influenced particle aggregation in the early Solar Syst...

Chondrules are thought to play a crucial role in planet formation, but the mechanisms leading to their formation are still a matter of unresolved discussion. So far, experiments designed to understand chondrule formation conditions have been carried out only under the influence of terrestrial gravity. In order to introduce more realistic conditions...

Earth's lower mantle most likely mainly consists of ferropericlase, bridgmanite, and a CaSiO3- phase in the perovskite structure. If separately trapped in diamonds, these phases can be transported to Earth's surface without reacting with the surrounding mantle. Although all inclusions will remain chemically pristine, only ferropericlase will stay i...

The origin of diamonds in ureilite meteorites is a timely topic in planetary geology as recent studies have proposed their formation at static pressures >20 GPa in a large planetary body, like diamonds formed deep within Earth's mantle. We investigated fragments of three diamond-bearing ureilites (two from the Almahata Sitta poly-mict ureilite and...

The formation of chondrules in the solar nebula is still an enigmatic process. In order to reconstruct this process, we performed a chondrule formation experiment aboard the International Space Station (ISS), called EXCISS. The purpose of the EXCISS experiment is to acquire new insights in chondrule formation by “nebular lightnings”. During the exp...

Diamonds are unrivalled in their ability to record the mantle carbon cycle and mantle fO2 over a vast portion of Earth’s history. Diamonds’ inertness and antiquity means their carbon isotopic characteristics directly reflect their growth environment within the mantle as far back as ∼3.5 Ga. This paper reports the results of a thorough secondary ion...

Introduction: We report rhyolitic (micrographic granite) rock clasts and SiO2 grains within a proto-brec-cia clast of the meteorite Northwest Africa 8171 (NWA 8171), a paired stone with Martian regolith breccia NWA 7034 [1,2].

Detection of rare earth elements (REE) is commonly performed with destructive techniques such as (LA)-ICP-MS or coupled to a destructive sample preparation. When investigating unique geological samples, such as cometary, asteroidal or interstellar material from sample return missions or inclusions in deep-Earth diamonds, a non-destructive method is...

The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course...

Nanograins (≪1 μm) are common in the principal slip zones of natural and experimental faults, but their formation and influence on fault mechanical behavior are poorly understood. We performed transmission Kikuchi diffraction (spatial resolution 20–50 nm) on the principal slip zone of an experimental carbonate gouge (50 wt% calcite, 50 wt% dolomite...

Northwest Africa (NWA) 12379 is a new metal-rich chondrite with unique characteristics distinguishing it from all previously described meteorites. It contains high Fe,Ni-metal content (∼ 70 vol.%) and completely lacks interchondrule matrix; these characteristics are typical only for metal-rich carbonaceous (CH and CB) and G chondrites. However, cho...

We report on the mineralogy, petrography, and in situ oxygen isotopic composition of twenty-five ultrarefractory calcium-aluminum-rich inclusions (UR CAIs) in CM2, CR2, CH3.0, CV3.1―3.6, CO3.0―3.6, MAC 88107 (CO3.1-like), and Acfer 094 (C3.0 ungrouped) carbonaceous chondrites. The UR CAIs studied are typically small, < 100 µm in size, and contain,...

Fine-grained CAIs with Group II rare earth element (REE) patterns condensed from a gaseous reservoir from which the ultrarefractory (UR) REEs had been removed. The carriers of UR REEs are poorly known. Here we report on the mineralogy, petrography and O-isotope compositions of 25 CAIs, presumably UR (REEs have not yet measured), from CR2, CM2, C3.0...

Inclusions in diamonds can tell us much of the deep and inaccessible portions of our planet including its mineralogy and the deeper effects of plate tectonics. Recently, great attention has been given in particular to those inclusions which classify their diamond hosts as “super-deep” or “sublithospheric” diamonds, which comprise only ~ 1% of the e...

We report the first natural occurrence and single-crystal X?ray diffraction study of the Fe-analog of wadsleyite [a = 5.7485(4), b = 11.5761(9), c = 8.3630(7) A, V = 556.52(7) A3; space group Imma], spinelloid-structured Fe2SiO4, a missing phase among the predicted high-pressure polymorphs of ferroan olivine, with the composition (Fe2+1.10Mg0.80Cr3...

Northwest Africa (NWA) 12379 is a new metal-rich chondrite with unique characteristics which distinguish it from meteorites of any previously described chondrite groups. Chondrule sizes, textures, mineral chemistry, and O-isotope composition suggest affinity to metamorphosed (type 3 range) ordinary chondrites (OCs). However, high metal content (~70...

Shock is often given as the cause for many observations in meteorites due to the assumed previous exposure of most meteorites to at least one impact event that ultimately led to their ejection from their parent body. Here we present electron backscatter diffraction (EBSD) results on a substantially shocked dunitic achondrite, chassignite Northwest...

A novel plug-and-play setup based on polycapillary X-ray optics enables 3D confocal XRF and XAS down to 8×8×11 µm³ (17 keV) at the ESRF CRG beamline DUBBLE, BM26A. A complete description and analytical characterization is presented, together with 2 recently performed experimental cases. In Deep Earth diamond SL-FFM 16, an Olivine rich inclusion was...

“Super-deep” diamonds are thought to have a sub-lithospheric origin (i.e. below ~300 km depth) because some of the mineral phases entrapped within them as inclusions are considered to be the products of retrograde transformation from lower-mantle or transition-zone precursors. CaSiO3-walstromite, the most abundant Ca-bearing mineral inclusion found...

Motivating the next generation of space explorers is one important task of a space agency. In order to maintain a skillful workforce in the field of aerospace engineering and related natural sciences, it is essential to get in contact with young people of all ages and to show them what the fields of Science, Technology, Engineering and Mathematics...

Introduction: The unbrecciated, ultramafic, monomict, main group (95%) of ureilites are thought to have formed in the mantle of a large, differentiated carbon-rich asteroid that has since been disrupted [1]. The remaining ~5% of ureilites are polymict breccias thought to represent the regolith on the surface or near-surface environment of the ureil...

Using X-ray absorption near edge structure spectroscopy, information on the local chemical structure and oxidation state of an element of interest can be acquired. Conventionally, this information can be obtained in a spatially resolved manner by scanning a sample through a focussed X-ray beam. Recently, full-field methods have been developed to ob...

“Super-deep” diamonds are thought to crystallize between 300 and 800 km depth because some of the inclusions trapped within them are considered to be the products of retrograde transformation from lower mantle or transition zone precursors. In particular, single inclusion CaSiO3-walstromite is believed to derive from CaSiO3-perovskite, although its...

A unique set of diamonds with a ‘milky’ optical appearance from the Rio Soriso placer deposit in the Juina area, Mato Grosso, Brazil was studied by combined transmission electron microscopy (TEM) and fourier transform infrared (FTIR) spectroscopy. The main characteristics of the studied samples are large numbers of randomly distributed {111}-facete...

Introduction: The unbrecciated, ultramafic, monomict, main group (95%) of ureilites are thought to have formed in the mantle of a large, differentiated carbon-rich asteroid that has since been disrupted [1]. The remaining ~5% of ureilites are polymict breccias thought to represent the regolith on the surface or near-surface environment of the ureil...

Energy dispersive X-ray spectroscopy (EDX) performed using scanning transmission electron microscopy (STEM) in combination with a windowless detector set-up allows high-resolution imaging and chemical composition mapping even of light elements present in low concentrations. The used TEM-system combines a field emission electron source with four sil...

Inclusions in diamonds may provide direct samples from the otherwise inaccessible Earth's lower mantle, as was first suggested almost thirty years ago. Nevertheless, it is only in the last two decades that diamonds of a deeper origin have been identified as minor components from a number of kimberlitic and alluvial diamond deposits worldwide [1, an...

Expectations regarding structural deformation of asteroidal meteorites have typically revolved around impact-induced shock metamorphism or the gravity-driven axial compression of cumulates at the base of magma chambers. Recent structural analyses, however, of several olivine-rich diogenites (harzburgites) reveal solid-state plastic deformation not...

Diamonds are considered the unique way to trap and convey real fragments of deep material to the surface of our planet. Over the last thirty years, great strides have been made in understanding of Earth's lower mantle, mainly thanks to technological and instrumental advances; nevertheless, it is only in the last two decades that a whole range of in...

The new ESRF ID16B-NA Nanoanalysis beamline has been applied for the first time to perform XRF imaging with a resolution level down to a few tens of nanometers on rare geological materials: meteoritic fragments from achondrite NWA 6693 and diamond inclusions. The instrument proved to be an extremely valuable tool for mapping samples containing subm...

The NASA Stardust mission used silica aerogel slabs to slowly decelerate and capture impinging cosmic dust particles for return to Earth. During this process, impact tracks are generated along the trajectory of the particle into the aerogel. It is believed that the morphology and dimensions of these tracks, together with the state of captured grain...

Hard X-ray, quantitative, fluorescence elemental imaging was performed on the ID22NI nanoprobe and ID22 microprobe beam lines of the European Synchrotron Research facility (ESRF) in Grenoble, France, on eight interstellar candidate impact features in the framework of the NASA Stardust Interstellar Preliminary Examination (ISPE). Three features were...

With the discovery of bona fide extraterrestrial materials in the Stardust Interstellar Dust Collector, NASA now has a fundamentally new returned sample collection, after the Apollo, Antarctic meteorite, Cosmic Dust, Genesis, Stardust Cometary, Hayabusa, and Exposed Space Hardware samples. Here, and in companion papers in this volume, we present th...

Here, we report the identification of 69 tracks in approximately 250 cm2 of aerogel collectors of the Stardust Interstellar Dust Collector. We identified these tracks through Stardust@home, a distributed internet-based virtual microscope and search engine, in which > 30,000 amateur scientists collectively performed >9 9 107 searches on approximatel...

We report the quantitative characterization by synchrotron soft X-ray spectroscopy of 31 potential impact features in the aerogel capture medium of the Stardust Interstellar Dust Collector. Samples were analyzed in aerogel by acquiring high spatial resolution maps and high energy-resolution spectra of major rock-forming elements Mg, Al, Si, Fe, and...

We discuss the inherent difficulties that arise during "ground truth" characterization of the Stardust interstellar dust collector. The challenge of identifying contemporary interstellar dust impact tracks in aerogel is described within the context of background spacecraft secondaries and possible interplanetary dust particles and beta-meteoroids....

Under the auspices of the Stardust Interstellar Preliminary Examination, picokeystones extracted from the Stardust Interstellar Dust Collector were examined with synchrotron Fourier transform infrared (FTIR) microscopy to establish whether they contained extraterrestrial organic material. The picokeystones were found to be contaminated with varying...

Here, we report analyses by synchrotron X-ray fluorescence microscopy of the elemental composition of eight candidate impact features extracted from the Stardust Interstellar Dust Collector (SIDC). Six of the features were unambiguous tracks, and two were crater-like features. Five of the tracks are so-called "midnight" tracks-that is, they had tra...

The NASA Stardust spacecraft exposed an aerogel collector to the interstellar dust passing through the solar system. We performed X-ray fluorescence element mapping and abundance measurements, for elements 19 <= Z <= 30, on six "interstellar candidates," potential interstellar impacts identified by Stardust@Home and extracted for analyses in picoke...

On the basis of an interstellar dust model compatible with Ulysses and Galileo observations, we calculate and predict the trajectories of interstellar dust (ISD) in the solar system and the distribution of the impact speeds, directions, and flux of ISD particles on the Stardust Interstellar Dust Collector during the two collection periods of the mi...

The Stardust Interstellar Preliminary Examination team analyzed thirteen Al foils from the NASA Stardust interstellar collector tray in order to locate candidate interstellar dust (ISD) grain impacts. Scanning electron microscope (SEM) images reveal that the foils possess abundant impact crater and crater-like features. Elemental analyses of the cr...

Seven particles captured by the Stardust Interstellar Dust Collector and returned to Earth for laboratory analysis have features consistent with an origin in the contemporary interstellar dust stream. More than 50 spacecraft debris particles were also identified. The interstellar dust candidates are readily distinguished from debris impacts on the...

The ultimate origin of water in the Earth's hydrosphere is in the deep Earth--the mantle. Theory and experiments have shown that although the water storage capacity of olivine-dominated shallow mantle is limited, the Earth's transition zone, at depths between 410 and 660 kilometres, could be a major repository for water, owing to the ability of the...

Fine grained material in the lithic clasts of the CB/CH-like meteorite Isheyevo is highly enriched in 15 N. No direct in situ correlation between highly 15 N enriched hotspots (up to ~ +4000‰) [1] and distinct mineral phases could be ascertained so far. Here we report on a new attempt to combinde TEM and NanoSIMS techniques to identify primary and...

Using synchrotron-based X-ray diffraction measurements, we identified crystalline material in two particles of extraterrestrial origin extracted from the Stardust Interstellar Dust Collector. The first particle, I1047,1,34 (Hylabrook), consisted of a mosaiced olivine grain approximately 1 mu m in size with internal strain fields up to 0.3%. The uni...

We take a closer look at the schlieren features in Zone B of the harzburgite NWA 5480, comparing them structurally and texturally with the olivine-dominated Zone A to gain further insight into the deformation history of this olivine-rich diogenite.

We report on transmission electron microscopy (TEM) investigations of two mineralogically unusual stardust silicates to constrain their circumstellar condensation conditions. Both grains were identified by high spatial resolution nano secondary ion mass spectrometry (NanoSIMS) in the Acfer 094 meteorite, one of the most pristine carbonaceous chondr...

Some preliminary results of nano-SXRF and SXRD measurements of presolar graphite grains are presented to demonstrate the advantanges of this method.

Diogenite meteorites are thought to represent mantle rocks that formed as cumulates in magma chambers on 4 Vesta or a similar differentiated asteroid. Northwest Africa 5480 is a harzburgitic diogenite, composed mainly of heterogeneously distributed olivine and orthopyroxene. Here we present a microstructural analysis of olivine grains from Northwes...

Here we report a new attempt to apply non-destructive in-situ Synchrotron XRF and XRD techniques to three presolar graphite grains from Orgueil separates: 2 low-density grains and 1 high-density grain.

Numerous petrologic and geochemical studies so far on the howardite, eucrite, and diogenite (HED) meteorites have produced various crystallization scenarios for their parent body, believed to be the differentiated asteroid 4 Vesta. Structural analyses of diogenites can reveal important insights into postcrystallization deformation on the parent bod...

A new method for the quantification of X-ray fluorescence (XRF) was derived based on the fundamental parameter method (FPM). The FPM equations were adapted to accommodate the special case of confocal nano-XRF, i.e. X-ray nano-beam excitation coupled with confocal detection, taking into account the special characteristics of the detector channel pol...

Seven eclogite samples from 223 to 584 m depths in the Chinese Continental Scientific Drilling main borehole (CCSD-H) in the Sulu ultrahigh-pressure metamorphic (UHPM) terrane, Eastern China, were studied by transmission electron microscopy (TEM), in order to characterise their microstructures. We observed, among others, omphacite, jadeitic diopsid...

A stream of 1-20 μm sized mineral inclusions having the negative crystal shape of its host within an "ultra-deep" diamond from Rio Soriso (Juina area, Mato Grosso State, Brazil) has been studied with confocal μ-X-ray absorption near edge structure (μXANES) at the Fe K and Mn K edges. This technique allows the three-dimensional nondestructive specia...

Results of structural analysis performed on HED meteorites (NWA 2696, Camel Donga, NWA 5480) using electron backscatter diffraction (EBSD), to measure the crystallographic orientation of each crystal to discover any lattice preferred orientation.

Introduction: In 2000 and 2002 the Stardust Mission exposed aerogel collector panels for a total of about 200 days to the stream of interstellar grains sweeping through the solar system [1]. The material was brought back to Earth in 2006. The goal of this work is the laboratory calibration of the collection process by shooting high speed [5 -30km/s...

Special Issue: 74th Annual Meeting of the Meteoritical Society, August 8-12, 2011, London, U.K.