Origin of 16O-rich fine-grained Ca-Al-rich inclusions of different mineralogy and texture
Year: 2019
Type: article
Source: Geochemistry
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, New Mexico State University, Nuclear Safety and Security Commission, Johnson Space Center, University of California, Los Angeles, Laboratory Directed Research and Development, Lawrence Livermore National Laboratory
Awards: G1088636562, THE RESEARCH OUTLINED IN THIS PROPOSAL IS DIRECTED TOWARDS UNDERSTANDING THE NATURE AND ORIGIN OF A VARIETY OF COMPONENTS INCHONDRITIC METEORITES IN THE CONTEXT OF EARLY SOLAR NEBULAR AND PARENT BODY EVOLUTION. THE RESEARCH SPECIFICALLY ADDRESS NASA STRATEGIC GOAL 2 TO `ADVANCE SCIENTIFIC KNOWLEDGE OF THE ORIGIN AND HISTORY OF THE SOLAR SYSTEM AND THE POTENTIAL FOR LIFE ELSEWHERE . THE GOALS OF THE RESEARCH ARE TO UNRAVEL THE COMPLEX SEQUENCE OF EVENTS THAT PRODUCED THE CHEMICALLY AND MINERALOGICALLY DIVERSE ASSEMBLAGES OBSERVED IN PRIMITIVE METEORITES. WE WILL CARRY OUT MINERALOGICAL PETROLOGIC AND ISOTOPIC STUDIES USING A VARIETY OF MICROBEAM TECHNIQUES (SEM EPMA FIB/TEM NANOSIMS AND SXRF MICROPROBE) AS WELL AS STABLE ISOTOPE TECHNIQUES IN A COLLABORATIVE EFFORT WITH SEVERAL OTHER RESEARCH GROUPS. OUR PROPOSED STUDIES ARE DIVIDED INTO FOUR SPECIFIC AREAS: 1) MINERALOGICAL AND STABLE ISOTOPIC STUDIES TO CONSTRAIN AQUEOUS ALTERATION PROCESSES IN CR CHONDRITES 2) MICROSTRUCTURAL AND STABLE ISOTOPIC STUDIES OF AMEBOID OLIVINE AGGREGATES (AOAS) AND CAIS IN CO3 CHONDRITES TO CONSTRAIN THEIR FORMATION AND THERMAL HISTORIES. 3) EPMA AND TEM STUDIES OF METASOMATIC AND METAMORPHIC EFFECTS IN REFRACTORY INCLUSIONS (AOAS AND CAIS) CO3 CHONDRITES 4) TEM AND TRACE ELEMENT STUDIES OF SULFIDES IN CM CHONDRITES TO CONSTRAIN THEIR FORMATIONAL AND THERMAL HISTORIES. FOR RESEARCH TASK 1 WEWILL ALSO EXAMINE THE MINERALOGICAL EVOLUTION OF MATRICES IN CR CHONDRITES AS INDICATORS OF PROGRESSIVE ALTERATION FOCUSING ON THE ROLE OF HYDRATED AMORPHOUS MATERIAL AS AN INDICATOR OF THE INTENSITY OF ALTERATION. THIS WORK WILL INVOLVE COORDINATED FIB/TEM IR NANOSIMS HYDROGEN AND OXYGEN ISOTOPIC ANALYSES TO CONSTRAIN THE PROGRESSIVE ALTERATION OF CR CHONDRITE MATRICES IN MORE DETAIL. WE WILL ALSO STUDY THE MECHANISMS OF HYDRATION OF SILICATE GLASS IN CHONDRULES IN CR CHONDRITES TO CONSTRAIN THE ALTERATION MECHANISM AND PROCESSES OF ELEMENTAL MASS TRANSPORT AND ELEMENTAL AND ISOTOPIC EXCHANGE. FOR RESEARCH TASK 2 WE WILL CARRY OUTCOORDINATED FIB/TEM AND NANOSIMS OXYGEN ISOTOPIC STUDIES OF THE REFRACTORY COMPONENT OF AMEBOID OLIVINE AGGREGATES AND CAIS IN CO CHONDRITES TO CONSTRAIN THEIR FORMATION AND THERMAL HISTORIES. IN PARTICULAR WE WILL FOCUS ON AOAS AND CAIS THAT SHOW EVIDENCE OF COMPLEX THERMAL HISTORIES THAT MAY BE INDICATIVE OF TRANSPORT AND INTERACTION WITH THE GAS PHASE IN DIFFERENT REGIONS OF THE SOLAR NEBULA. A COMPONENT OF THIS WORK WILL INVOLVE THE STUDY OF REFRACTORY METAL NANOPARTICLES WHICH WE HAVE RECENTLY DISCOVERED IN SITU IN AOAS IN CO3 CHONDRITES. THIS EFFORT WILL HELP CONSTRAIN THE POTENTIAL ORIGINS OF REFRACTORY METAL ALLOYS WHICH OCCUR IN OTHER TYPES OF CARBONACEOUS CHONDRITES. FOR RESEARCH TASK 3 WE WILL INVESTIGATE THE DETAILED RESPONSE OF CAIS AND AOAS IN CO3 CHONDRITES TO THERMAL METAMORPHISM AND METASOMATISM USING SEM EPMA AND FIB/TEM IN ORDER TO DEVELOP A MORE THOROUGH UNDERSTANDING OF THE INTERRELATIONSHIPS BETWEEN THESE TWO PROCESSES AND CONSTRAIN THE ROLE OF FLUIDS IN THE ALTERATION PROCESSES. FOR RESEARCH TASK 4 WE WILL PERFORM COORDINATE SEM EPMA FIB/TEM AND SXRF STUDIES OF PRISTINE SULFIDES IN CM CHONDRITES IN ORDER TO UNDERSTAND THE NEBULAR FORMATION AND SUBSEQUENT COOLING HISTORIES OF SULFIDE MINERALS. THIS WORK WILL PROVIDE CONSTRAINTS ON THE THERMAL HISTORIESOF CHONDRULES PARTICULARLY TYPE IIA CHONDRULES IN THIS TWO CHONDRITE GROUP. AS PART OF THIS EFFORT WE WILL DEVELOPMENT TECHNIQUES TO CARRY OUT HIGH SPATIAL RESOLUTION TRACE ELEMENT (CHALCOPHILE) ANALYSES ON FIB SECTIONS USING THE MODIFIED SXRF BEAM LINE AT THE ADVANCED PHOTON SOURCE ARGONNE NATIONAL LABORATORY AND THE NEW NSLS II FACILITY AT BROOKHAVEN NATIONAL LABORATORY THAT WILLCOME ON LINE IN 2015., G1356433355, G14554683, G2145270357, G233665131, G2717806384, THE RESEARCH OUTLINED IN THIS PROPOSAL WILL ADDRESS SOME OUTSTANDING QUESTIONS REGARDING THE ORIGIN OF SOLID ORGANIC MATTER (OM) IN CARBONACEOUS CHONDRITE METEORITES. ALTHOUGH STUDIES OF BULK OM RESIDUES EXTRACTED FROM METEORITES HAVE PROVIDED REMARKABLE DATA ABOUT THE CHARACTERISTICS OF THIS MATERIAL IT IS CLEAR FROM RECENT COORDINATED IN SITU NANOSIMS TEM AND STXM STUDIES THAT THERE IS A REMARKABLE ISOTOPIC TEXTURAL AND STRUCTURAL DIVERSITY IN OM AT THE MICRO TO NANOSCALE. WE PROPOSE TO CARRY OUT CORRELATEDMINERALOGIC SPECTROSCOPIC AND ISOTOPIC STUDIES OF ORGANIC MATERIALS IN SITU WITHIN THE MATRICES OF PRIMITIVE CARBONACEOUS CHONDRITESUSING A COMBINATION OF NANOSIMS-FIB/TEM-STXM TECHNIQUES. THE PROPOSED RESEARCH BRINGS TOGETHER INDIVIDUALS WITH CONSIDERABLE EXPERTISE IN NANOSIMS ANALYSIS STXM SPECTROSCOPY AND TEM ANALYSIS IN A COLLABORATIVE ENDEAVOR TO GAIN NEW INSIGHTS INTO DIFFERENT ASPECTS OF THE FORMATION AND PROCESSING OF OM. THESE STUDIES WILL PROVIDE SIGNIFICANT NEW INSIGHTS INTO SUCH QUESTIONS AS: A) HOW OM WAS DISTRIBUTED IN NEBULAR DUST B) THE RELATIONSHIPS BETWEEN SILICATE DUST AND ORGANIC MATTER PRIOR TO ACCRETION AND C) HOW ORGANIC MATERIAL WAS PROCESSED WITHIN ASTEROIDAL PARENT BODIES. THE SPECIFIC RESEARCH TASKS THAT WE PROPOSE WILL FIRST ADDRESS THE ISSUESOF ELECTRON BEAM DAMAGE OF OM CAUSED BY TEM STUDIES THAT MAY AFFECT SUBSEQUENT ISOTOPIC AND CHEMICAL ANALYSES BY NANOSIMS AND STXM. SECOND WE WILL EXAMINE THE DISTRIBUTION MORPHOLOGY GRAIN SIZE AND CHEMISTRY OF ISOTOPICALLY ANOMALOUS (D N AND C) AND ISOTOPICALLY NORMAL OM GRAINS IN PRISTINE TYPE 3 CHONDRITIC METEORITES. OUR GOAL WILL BE TO UNDERSTAND THE DIVERSITY OF ORGANICMATERIALS PRESENT IN THESE METEORITES CONSTRAIN THEIR POSSIBLE ORIGINS AND DETERMINE WHETHER THE DIFFERENT CHONDRITE GROUPS ALL ACCRETED THE SAME RESERVOIR OF ORGANIC GRAINS. IN ADDITION WE WISH TO UNDERSTAND IF THERE ARE MORPHOLOGICAL COMPOSITIONAL AND STRUCTURAL DIFFERENCES BETWEEN ISOTOPICALLY ANOMALOUS AND NORMAL OM GRAINS. WE WILL ALSO EXAMINE THE EFFECTS OF AQUEOUS ALTERATION ON THEEVOLUTION OF OM IN CI CM AND CR CHONDRITES TO UNDERSTAND IF REACTIONS WITHIN AN AQUEOUS MEDIUM RESULT IN SYNTHESIS OF NEW OM GRAINS OR REDISTRIBUTION OR MODIFICATION OF EXISTING OM GRAINS. FURTHER WE WILL DETERMINE IF HETEROGENEITY DURING THE EARLIEST STAGES OF AQUEOUS ALTERATION IS THE RESULT OF LOCALIZED MELTING OF ICE THAT WAS ACCRETED AS COMPOSITE OM/WATER ICE GRAINS. FINALLY WE WILL EXAMINE THE QUESTION OF WHETHER D ANOMALOUS OM GRAINS EXCHANGED HYDROGEN ISOTOPES WITH WATER TO FORM PHYLLOSILICATE PHASES WITH ELEVATED D/H RATIOS DURING AQUEOUS ALTERATION., G3781741884, G4401703637, G4612008882, G5961924358, FORMATION & ALTERATION HISTORIES OF CHONDRITIC MATERIALS, G6672310739, G6754864953, G7264490812, G7644260748, G7776117750, WE PROPOSE TO CARRY OUT COORDINATED PETROLOGIC MINERALOGICAL AND ISOTOPIC INVESTIGATIONS OF EARLY-FORMED NEBULAR CONDENSATES PRESERVED IN CHONDRITIC METEORITES IN HOPES OF BETTER CONSTRAINING THE EARLIEST ENVIRONMENTS IN THE SOLAR NEBULA. THIS PROJECT IS AIMED TO SHED LIGHT ON THE (ASTRO)PHYSICAL AND CHEMICAL PROCESSES THAT RESULTED IN THE FORMATION OF SOLAR SYSTEM S FIRST SOLIDS AND THE ISOTOPIC INVENTORIES IN WHICH THESE SOLIDS CONDENSED. THIS IS DIRECTLY RELEVANT TO THE GOALS OF EMERGING WORLDS SOLICITATION TO UNDERSTAND THE FORMATION AND EARLY EVOLUTION OF THE SOLAR SYSTEM AND THE RESEARCH AREAS OF STUDIES OF THE MATERIALS PRESENT AND PROCESSES THAT LED TO THE ONSET OF SOLAR SYSTEM FORMATION AND STUDIES OF ALL ASPECTS OF MATERIALS AND PROCESSES OCCURRING IN AND AFFECTING THE PROTOPLANETARY DISK INCLUDING THOSE OCCURRING ON BODIES OF ANY SIZE THAT MAY HAVE FORMED AT THIS STAGE OF SOLAR SYSTEM EVOLUTION . CA-AL-RICH INCLUSIONS (CAIS) ARE THE OLDEST DATEABLE SOLIDS IN THE SOLAR SYSTEM WITH A RADIOMETRIC AGE OF 4.567 BILLION YEARS DETERMINED ON A FEW LARGE CAIS. IN THIS PROPOSED WORK WE PLAN TO STUDY TWO SUBTYPES OF CAIS. THE FIRST SUBTYPE NAMELY FINE-GRAINED CAIS CONSISTS OF AGGREGATES OF MICRON-SIZED DUST THAT DIRECTLY CONDENSED OUT OF THE NEBULAR. THEREFORE THE CHEMICAL AND ISOTOPIC CHARACTERISTICS OF THE FINE-GRAINED CAIS REFLECT THE CONDITIONS OF THE NEBULAR GAS IN WHICH THESE CAIS FORMED. THE SECOND SUBTYPE OF CAIS WHICH ARE ALSO EARLY NEBULA CONDENSATES IS HIBONITE ( CORUNDUM) BEARING INCLUSIONS. THEY ARE THERMODYNAMICALLY PREDICTED TO BE THE FIRST MINERAL PHASES DIRECTLY CONDENSING FROM A COOLING GAS OF SOLAR COMPOSITION AROUND 1600 1770 K AT ~10-3 BAR. SUCH INCLUSIONS PROVIDE AN EXCELLENT OPPORTUNITY TO STUDY THE ENVIRONMENT IN THE HOTTEST STAGE OF THE SOLAR SYSTEM HISTORY; HOWEVER THEY HAVE NOT BEEN WELL STUDIED DUE TO THEIR RARITY AND SMALL SIZES (USUALLY 50 MICRONS OR LESS). IN THIS PROPOSAL WE WILL FOCUS ON THE CO 3.0 CHONDRITES AS THEY ARE KNOWN TO BE MORE PRISTINE AND HAVE BEEN REPORTED TO HAVE MORE ENRICHED IN FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS THAN OTHER GROUPS OF CARBONACEOUS CHONDRITES. OUR COLLABORATORS PROF. BREARLEY DRS. KROT KELLER AND HAN HAVE IDENTIFIED SOME FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS IN CO3.0 CHONDRITES. WE WILL ALSO PERFORM IN-SITU SEARCHES FOR MORE OF THESE RARE INCLUSIONS AND PETROLOGICAL STUDIES OF THEM ON THICK SECTIONS WITH SCANNING ELECTRON MICROSCOPY FOLLOWED BY OXYGEN ISOTOPIC MEASUREMENTS WITH THE NEW CAMECA IMS-1290 AT UCLA TO BETTER CONSTRAIN THE OXYGEN ISOTOPE RESERVOIRS IN THE GAS. ONCE THE OXYGEN ISOTOPE ANALYSES ARE FINISHED MEASUREMENTS FOR 26AL-26MG (CHRONOLOGY) AND 10BE-10B (IRRADIATION HISTORIES OF DUST AND GAS) SYSTEMS WILL BE ALSO PERFORMED ON THE IMS-1290 ION MICROPROBE BY USING A RADIO-FREQUENCY OXYGEN ION SOURCE WHOSE SMALL YET INTENSE PRIMARY ION SPOT WILL ALLOW FOR ISOTOPE ANALYSIS OF INDIVIDUAL PHASES WITHIN A SMALL INCLUSION. WHEN ISOTOPIC ANALYSIS IS ACCOMPLISHED PECULIAR SAMPLES (E.G. CARRY UNUSUAL ISOTOPIC ANOMALIES) WILL BE SENT TO OUR COLLABORATORS LABORATORIES FOR TRANSMISSION ELECTRON MICROSCOPY (TEM) STUDY. A COMPREHENSIVE PICTURE OF THE FORMATION ENVIRONMENTS OF FINE-GRAINED CAIS AND HIBONITE ( CORUNDUM) BEARING INCLUSIONS WILL BE CONSTRUCTED BY USING ALL THE MINERALOGY PETROLOGY AND ISOTOPIC CHARACTERISTICS OBTAINED IN THIS PROPOSED WORK., G991281326
OpenAlex ID: W2975564888