PRL PLATINUM PLANETARY SEMINAR SERIES - PPPSS

Title : Origin and evolution of nitrogen on planetary bodies in the inner solar system

Date : 20-01-2022
Time : 14:30:00
Speaker : Dr. Evelyn Füri, Centre de Recherches Pétrographiques et Géochimiques (CRPG, CNRS-UL), France
Venue : Online

Abstract

Knowledge of the origin of nitrogen on Earth is of particular importance to understanding the development of conditions favorable to the emergence of prebiotic molecules and the maintenance of life on rocky planets. However, the origin and timing of the accretion of nitrogen on Earth remains a subject of controversy. In this talk, I will present new data obtained by secondary ion mass spectrometry (SIMS) analyses of extraterrestrial melt inclusions. First, I will show that olivine-hosted melt inclusions in angrites and martian meteorites are key for constraining the source(s) and timing of nitrogen delivery to planetary bodies in the inner solar system. However, the effects of planetary formation processes (core formation, magma ocean crystallization and degassing) on the original elemental and isotopic composition of planetary mantles still need to be investigated.

Title : How well can we link meteorites to asteroids

Date : 13-01-2022
Time : 09:30:00
Speaker : Prof. Thomas Burbine , Department of Astronomy, Mount Holyoke College, USA
Venue : Online

Abstract

Asteroids are the remaining planetesimals that helped form the terrestrial and Jovian planets. Asteroids, which are the parent bodies of almost all meteorites, are almost entirely observed remotely using Earth- and space-based telescopes with only a few bodies studied up close by spacecraft missions. The chemical and isotopic compositions of meteorites can be determined with high precision in laboratories on Earth; however, remote observations of asteroids give geochemical information. In this seminar asteroid-meteorite relationship will be discussed.

Title : Nucleosynthetic heterogeneity in the early solar system: insights from Nd isotopes

Date : 06-01-2022
Time : 15:30:00
Speaker : Dr. Nikitha Susan Saji, Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Denmark
Venue : Online

Abstract

Isotopic variability from heterogeneous distribution of presolar dust in the solar protoplanetary disk is now well-established for a number of elements. Yet, significant uncertainty exists regarding the inventory of presolar dust populations that were initially present in the protosolar molecular cloud and their eventual aggregation into planets and planetesimals. In this talk, I will review what high precision Nd isotope measurements of meteorites and their components tell us about the diversity of nucleosynthetic components that contributed material to the nascent solar system and how they resulted in an apparent bifurcation of solar system materials into carbonaceous and non-carbonaceous suites.

Title : Chondrites and the early solar system

Date : 30-12-2021
Time : 16:30:00
Speaker : Dr. Yogita Kadlag, NCCR PlanetS advanced Post-Doctoral fellow, Universität Bern, Switzerland
Venue : Google meet

Abstract

Precursors of all solar system objects such as meteoroids, asteroids, comets, proto-planets, and planetary satellites were formed through physical and chemical processing (e.g. condensation-evaporation, variable heating, mixing, etc.) of nebular dust and gas of about 0.1% solar mass. To understand the role of initial chemical and isotopic heterogeneity and subsequent physicochemical processing of dust, gas and planetary precursors in the solar nebula, chemical and isotopic variations in the components of undifferentiated meteorites such as calcium-aluminum-rich inclusions, chondrules, matrix and Fe-Ni metal can be used as tracers. Here, I discuss examples of chondrules and separated components from unequilibrated chondrites to explore the origin of isotopic heterogeneities and processing of mm to cm scale objects within the first few million years of the solar system evolution.

Title : First Formed Solids: Records of the Earliest Times of the Solar System

Date : 23-12-2021
Time : 10:30:00
Speaker : Dr. Prajkta Mane , Visiting Scientist, Lunar and Planetary Institute (USRA), Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston TX 77058
Venue : Google meet

Abstract

Meteorites and their components can be used to unravel the history of the early Solar System. Carbonaceous chondrites are meteorites that originated from undifferentiated parent bodies that formed within a few million years of the beginning of the Solar System. These meteorites contain calcium-aluminum-rich inclusions (CAIs), which are the oldest dated solids forming in our Solar System at ~4.567 billion years old and thus preserve a record of the earliest stage of Solar System formation. The radiometric dating of these CAIs and other meteoritic components provides important time constraints on the events that occurred in the early Solar System, whereas textures and microstructures in these CAIs preserve the evidence of disk processes in them. In this talk, I will discuss the results of a coordinated multi-technique approach to analyzing CAIs and their components to reveal the timescales and conditions of their formation.

Title : Isotopic constraints on the conditions of chondrule formation in carbonaceous chondrites

Date : 16-12-2021
Time : 14:00:00
Speaker : Prof. Yves Marrocchi, Research Director at CNRS, Deputy Director of the CRPG, France
Venue : Google meet

Abstract

In this talk, I will review the recent measurements carried out on chondrules of carbonaceous chondrites for different isotopic systems (O, Si, Cr, Ti). I will use these data to discuss the different models of chondrule formation in the framework of both planetary and nebular scenarios.

Title : The Origins of Organic Matter and Amorphous Silicates in Meteorites – Clues from Nanoscale Investigations

Date : 09-12-2021
Time : 14:30:00
Speaker : Prof. Christian Vollmer, Institut für Mineralogie, WWU Münster, Germany
Venue : Google meet

Abstract

Pristine carbonaceous chondrites provide important samples of the very early solar nebula. These complex rocks recorded snapshots of events 4.56 Ga years ago that can be disentangled by advanced analytical techniques on Earth. One of the most challenging components to analyze within such chondrites is the so-called “matrix”, a fine-grained mixture of presolar dust, amorphous and crystalline silicates, organic matter, sulfides, and metal, in which larger constituents such as chondrules or refractory inclusions are embedded. Organic matter (OM) and amorphous silicates within chondrite matrix are specifically important, because they record crucial condensation and synthesis processes in the solar nebula and meteorite parent bodies, but are also prone to alteration and destruction. In this talk, I want to summarize recent work by high-spatial resolution analysis techniques (TEM, UltraSTEM, NanoSIMS) on amorphous silicates and organic matter in a variety of pristine carbonaceous chondrites. We analyzed the functional chemistry signatures of these unique materials by electron energy loss spectroscopy (EELS) and synchrotron X-ray spectroscopy methods (STXM) to disentangle complex formation pathways. Organic matter records very early biomolecule reaction pathways, whereas the chemical composition and Fe oxidation state of amorphous silicates within matrix regions can be analyzed to understand early solar nebula condensation and alteration processes.

Title : Sulfur isotope anomalies in Acfer 094 inherited from the Irradiation of the Protosolar Molecular Cloud by Massive Nearby Stars.

Date : 30-11-2021
Time : 18:00:00
Speaker : Dr. Lionel Vacher, Washington University St. Louis, USA
Venue : Online

Abstract

Spectral line (121.6 nm) and larger or smaller wavelengths produce MI anomalies that define distinct ∆36S/∆33S ratios. Young stars have strong emission at Lyman-alpha, while massive O and B stars dominate the interstellar UV flux. Thus, the photodissociation of H2S can serve to differentiate between massive stars and young T-Tauri stars as the astronomical source of isotope-selective photodissociation. Analysis of paired oxygen and sulfur isotope systematics in cosmic symplectite (COS)−a nm-scale intergrowth of 16O-poor magnetite and pentlandite−in the primitive carbonaceous chondrite Acfer 094 can provide unique insights into photochemical processing of Solar System materials. Acfer 094 shows similarities to cometary material and, therefore, may have formed in the outer Solar System where it could have incorporated 16O-poor water ice that also contained H2S ice like that detected in comets. Sulfur in COS may provide insights into the astrophysical environment for the Solar System formation. In this talk, I'll report the oxygen and sulfur isotopic composition of COS and determine the likely astrophysical UV source responsible for photochemical processing of Solar System solids.

Title : Serpentinization of iron-rich olivine and its potential for abiotic methane synthesis in planetary bodies

Date : 25-11-2021
Time : 14:30:00
Speaker : Dr. Alik Sundar Majumdar, Department of Applied Geology Indian Institute of Technology (Indian School of Mines) Dhanbad Jharkhand, India
Venue : https://meet.google.com/fns-cpjv-snn

Abstract

Serpentinization of olivine-rich ultramafic rocks are increasingly recognized to have been widespread in the solar system throughout its history. This process has gained particular attention among planetary scientists because it generates molecular hydrogen (H2) and methane (CH4), compounds that can supply metabolic energy to biological communities and contribute to greenhouse warming of planetary atmospheres. Following this, the talk will demonstrate a series of natural (meteorites) and experimental observations as well as thermodynamic models to show the pattern of secondary mineral formation and H2 generation during serpentinization of olivine as a function of Fe content and temperature. It will also be shown that serpentinization of Fe-rich olivine can generate substantially greater amounts of H2 per mole than is observed for serpentinization of Mg-rich olivine, depending on the magnitude of Fe (III) partitioning into serpentine phase. Thus, serpentinization on planetary bodies may have a greater potential to supply H2 vis-à-vis CH4 to support biological communities and enhance the atmospheric greenhouse warming than analogous processes on Earth.

Title : Constraining thermal processing of dust grains in space and on the surface of airless bodies through in-situ laboratory experiments

Date : 18-11-2021
Time : 09:30:00
Speaker : Dr. Pierre Haenecour, Lunar and Planetary Laboratory, The University of Arizona, Tucson, USA
Venue : Online

Abstract

Fine-grained material in chondritic meteorites typically consists of a mixture of crystalline and amorphous silicates, oxides, sulfides, Fe-Ni metal grains, and carbonaceous matter that accreted together from the solar protoplanetary disk. Some of these ‘primary’ phases were affected by secondary processing, including both heating and aqueous alteration, on their host asteroid. The response of these materials to secondary alteration is important for understanding active processes on the surfaces and within the chondrite-parent asteroids. Thermal metamorphism, in particular, could have played an important role in processes such as melting, volatile loss, elemental diffusion between grains, and driving hydrothermal processing. In my talk, I will discuss how we are using in-situ heating experiments inside electron microscopes to better understand the effect(s) of heating on the composition and microstructure of fine-grained materials.

Title : Heterogeneous accretion of volatiles to Earth's mantle reservoirs

Date : 12-11-2021
Time : 18:00:00
Speaker : Dr. Rita Parai, Washington University, U. S. A.
Venue : Online

Abstract

Earth’s interior retains volatiles (e.g., nitrogen, carbon, hydrogen and the noble gases) acquired during accretion. Solar, chondritic and cometary noble gases may all have contributed to terrestrial volatile reservoirs. This study shows that helium (He), neon (Ne) and xenon (Xe) isotopes of the upper mantle and the plume mantle source can only be explained if the latter reservoir had a low initial Xe abundance. A record of limited accretion of volatile-rich chondrites into the deep mantle compared to the upper mantle thus survives in the He-Ne-Xe signatures of mantle rocks today. Energetic impacts during accretion did not homogenize the growing planet, and early-formed 129Xe and 182W mantle heterogeneities may have survived through ~4.5 Gyr of mantle mixing due to a viscosity contrast originating from differential accreted water contents in the plume and upper mantle reservoirs.

Title : Entering an Unseen World: Biology vs. Science – Who sees further?

Date : 28-10-2021
Time : 18:00:00
Speaker : Dr. Frank Gyngard, Harvard, USA
Venue : Online

Abstract

Over the last many decades, there has been an undeniable advance in our ability to see into materials at the micro and nano scale, that not even the highest-powered optical microscope could reveal. >From meteorites to cells, this revolution has revealed to us the substructures and wonders of natural phenomena. This talk will focus on the parallels of applying NanoSIMS techniques to both biology and cosmochemistry/presolar grains. It will also give some general advice gleaned from the world of biology, in terms of grants, publications, and general outlook for future NanoSIMS studies. And for fun, you will also see the Chicago car tow lot!

Title : Nascent Sun & repetitive Super flares

Date : 21-10-2021
Time : 18:00:00
Speaker : Dr. Ritesh Mishra, Application Engineer, Cameca, India
Venue : Online

Abstract

The chronology of the early Solar system events during the first few millions years are presently constrained at a few 100 ka which is a few orders of magnitude larger than the typical time scale of a few 100-1000 years of evaporation, condensation, cooling, solar flaring events (FUor) etc.. Evidence of such a high resolution temporal record of a superflare from the young Sun during its birth inferred from fossil records of 7Be, 10Be will be presented in the talk.

Title : Minor and trace element concentrations in adjacent kamacite and taenite in the Krymka chondrite

Date : 14-10-2021
Time : 14:30:00
Speaker : Dr. Smail Mostefaoui, Paris, France
Venue : Online

Abstract

We report NanoSIMS in situ siderophile minor and trace element abundances in individual Fe-Ni metal grains in the unequilibrated chondrite Krymka (LL3.2). Associated kamacite and taenite of 10 metal grains in four chondrules and one matrix metal were analyzed for elemental concentrations of Fe, Ni, Co, Cu, Rh, Ir, and Pt. The results show large elemental variations among the metal grains. However, complementary and correlative variations exist between adjacent kamacite-taenite. This is consistent with the unequilibrated character of the chondrite and corroborates an attainment of chemical equilibrium between the metal phases. The calculated equilibrium temperature is 446 ± 9 °C. This is concordant with the range given in literature for the Krymka post-accretion thermal metamorphism. Based on Ni diffusivity in taenite, a slow cooling rate is estimated of the Krymka parent body that does not exceed ~1K Myr-1, which is consistent with cooling rates inferred by other workers for unequilibrated ordinary chondrites. Elemental ionic radii might have played a role in controlling elemental partitioning between kamacite and taenite. The bulk compositions of the Krymka metal grains have nonsolar (mostly subsolar) element/Ni ratios suggesting the Fe-Ni grains could have formed from distinct precursors of nonsolar compositions or had their compositions modified subsequent to chondrule formation events.

Title : Isotopic and elemental studies of presolar graphite grains and what they tell us about their parent stars

Date : 06-10-2021
Time : 18:00:00
Speaker : Dr. Manavi Jhadav, University of Louisiana, USA
Venue : Online

Abstract

The laboratory study of stardust or presolar grains is an important sub-field of astrophysics. It combines sophisticated chemical, structural, and isotopic laboratory measurements, on micron-sub-micron presolar particles, with the theoretical ideas of nucleosynthesis and stellar evolution that exist to understand astrophysical observations. Isotopic data for these grains reveal more precise information about their parent stars than do spectroscopic observations of circumstellar dust. The goal of laboratory measurements is to provide clues on the stellar environments in which the grains formed and on their subsequent histories. Additionally, investigations into the preservation of these grains in different meteorites provide information about early solar system conditions and chronology. These goals can be achieved by coordinated, multi-technique investigations of presolar grains in the laboratory. This talk will focus on results from coordinated, multi-technique measurements of presolar graphite grains and what they tell us about the stars that contributed presolar materials to our nascent Solar System.

Title : 26Al in AGB grains.

Date : 23-09-2021
Time : 19:00:00
Speaker : Dr. Nan Liu, Washington University St. Louis, USA
Venue : Online

Abstract

Presolar grains found in pristine meteorites are stellar relics that predate our solar system. They enable the study of bonafide stellar materials in the laboratory, where the full battery of modern micro-analytical techniques can be brought to bear on them. In this talk, I will present new NanoSIMS isotopic data of presolar SiC grains and discuss their stellar origins and 26Al production in low-mass stars in the light of astronomical observations for carbon stars and stellar models.

Title : Shock-induced incongruent melting of olivine and formation of natural Fe-bearing aluminous bridgmanite in ordinary chondrites.

Date : 16-09-2021
Time : 16:00:00
Speaker : Prof. Sujoy Ghosh, IIT Kanpur
Venue : Online

Abstract

The planet Earth was formed from a similar material that constitutes present-day asteroids. Olivine and bridgmanite are the most volumetrically abundant mineral of the Earth’s upper and lower mantle, and it is important to understand its formation mechanism to better comprehend the origin and evolution of planetary interiors. Olivine breaks down to bridgmanite and magnesiowüstite formed by the solid-state or melting of the olivine. Whereas, natural bridgmanites have been reported in only a few shocked meteorites; however, the composition of these specimens differs from plausible compositions of terrestrial bridgmanite. In this presentation, I will present our recent results which show the possible occurrence of bridgmanite and magnesiowüstite formed by incongruent melting of olivine in an ordinary chondrite (Kamargaon L6 chondrite) and the first natural occurrence of bridgmanite, observed in an ordinary chondrite, with a composition closest to the bridgmanite present in the Earth’s lower mantle. The bridgmanite in the ordinary chondrite (Katol L6 chondrite) has high Fe3+/Fe ratio and agrees with experimental predictions. The Katol chondrite may serve as a unique analogue for crystallization of bridgmanite during the final stages of magma ocean crystallization of the Earth.

Title : Micrometeorites on the Earth surface: Understanding their origin and properties.

Date : 02-09-2021
Time : 14:30:00
Speaker : Dr N G Rudraswami, National Institute of Oceanography (NIO) Goa
Venue : Online

Abstract

Throughout its history planet Earth has been continuously bombarded by high-speed extraterrestrial material. These are debris of comets and asteroids that are leftover material in the solar system, but additional sources may occasionally contribute. The Earth surface accretes a complex variety of these extra-terrestrial material at a rate of approximately 40,000 tons per annum. The dominant size fraction of these extra-terrestrial materials are in the range of few ten of µm to few mm. These sub-mm size particles called as micrometeorites (MMs) provide us an unique opportunity to study diverse collection of samples of solar system bodies in the laboratory. Many micrometeorites have shown textural, chemical, isotopic and trace element composition that can be linked to primitive chondrites such as CI and CM chondrites. Some of these particles are not found in meteorite studies indicate existence of diverse type of precursors in the asteroidal belt that is still not in our inventory. Most dust-sized cosmic particles undergo ablation and chemical alteration during atmospheric entry due to rapid frictional heating, which alters their original properties depending on the size, composition, entry velocity and angle. A comprehensive understanding of this process is essential in order to decipher their pre-entry characteristics. My talk will focus on understanding their chemical and isotopic properties of micrometeorites, that can enhance our overall understanding of these objects.

Title : Organics on Itokawa asteroid via analyses of Hayabusa samples.

Date : 26-08-2021
Time : 18:00:00
Speaker : Dr Queenie Chan, Royal Holloway, University of London, UK
Venue : Online

Abstract

Understanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. Such investigation necessitates the availability of pristine samples of astromaterials—samples that have not been compromised by terrestrial contamination, and thus preserve the intrinsic states of the materials’ physical, chemical, organic and other properties In this connection, the Hayabusa mission of the Japan Aerospace Exploration Agency (JAXA) is the first asteroidal sample return mission, which has successfully recovered regolith particles from the near-Earth S-type asteroid 25143 Itokawa in 2010. The Hayabusa particles were linked to LL ordinary chondrites based on mineralogy, chemistry and oxygen isotope compositions. Investigation of mineralogy, water and organic contents and other results an Itokawa particle will be discussed.

Title : Origin of the solar system

Date : 12-08-2021
Time : 14:00:00
Speaker : Prof. Sandeep Sahijpal, Punjab University
Venue : Online

Abstract