Meteoritics & Planetary Science最新文献

{"title":"The first discovery of a shocked, metasomatised CV3 chondrule-fragment in a (Al,Cu)-bearing micrometeorite","authors":"Giovanna Agrosì,&nbsp;Paola Manzari,&nbsp;Daniela Mele,&nbsp;Johan Villeneuve,&nbsp;Tiziano Catelani,&nbsp;Mattew J. Genge,&nbsp;Luca Bindi","doi":"10.1111/maps.70215","DOIUrl":"https://doi.org/10.1111/maps.70215","url":null,"abstract":"<p>We report the discovery of the second (Al,Cu)-alloy–bearing micrometeorite, FB-A2, recovered from Mount Gariglione (southern Italy), representing the sixth such occurrence worldwide. Although chondritic in nature, FB-A2 differs markedly from previously described microspherules. It is a scoriaceous micrometeorite dominated by silicates and contains a relict clast composed of Mg-rich olivine and pyroxene phenocrysts set in a Fe-rich silicate matrix. The particle rim hosts fine aggregates of phosphates, magnetite, Ni-bearing magnetite, and sulfides, whereas the interior contains nepheline crystals. A 120 μm (Al,Cu)-alloy grain occurs at one corner of the particle. The porphyritic texture of the clast indicates a chondrule fragment—the first identified in an (Al,Cu)-bearing micrometeorite—while polyhedral sub-grain boundaries and metal–sulfide veins record shock metamorphism. Iron-rich alteration of relict silicates is consistent with high-temperature (&lt;560 °C) metasomatism typical of CV3 chondrites and is supported by oxygen isotope compositions close to the Carbonaceous Chondrite Anhydrous Mineral Line. Brecciation of chondrule olivine suggests impact-induced fluid pressure excursions during early Solar System metasomatism, whereas impact melt enveloping elongate olivines indicates a later impact that introduced the (Al,Cu)-alloys. Overall, the texture, mineralogy, and isotopic composition of FB-A2 provide the most detailed constraints yet on the origin of (Al,Cu)-bearing micrometeorites and confirm a genetic link to the Khatyrka meteorite.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2269-2283"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70215","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geophysical update of the diameter of the Zhamanshin impact structure, Kazakhstan","authors":"Yoann Quesnel,&nbsp;Dilyara M. Kuzina,&nbsp;Jérôme Gattacceca,&nbsp;Minoru Uehara,&nbsp;Ayrat G. Kharisov,&nbsp;Dmitry D. Badyukov,&nbsp;Pierre Rochette","doi":"10.1111/maps.70218","DOIUrl":"https://doi.org/10.1111/maps.70218","url":null,"abstract":"<p>The rim of the 0.9-Ma-old Zhamanshin impact crater in Kazakhstan is considered to be almost completely exposed via a series of hills surrounding a central flat area, indicating an apparent diameter of 14 km. This would make Zhamanshin the second largest impact crater of the Quaternary period. However, the overall geometry of these hills is not circular, and there is no visible central uplift, raising doubts about this diameter estimate. In this work, we used a set of geophysical methods (magnetic and gravity field mapping, and passive seismic measurements) to better characterize the geometry of the impact structure. The new potential field data reveal residual anomaly maps with significant concentric features extending only 2.5 to 3 km away from the structure center. The passive seismic data were used to derive H/V spectra. Combined with previous drilling information and surface geology, it allows us to delineate the depth of the interface between the fractured bedrock and the post-impact sediments, which reveals a buried crater with a small central uplift. These new field geophysical data were combined with laboratory petrophysical measurements to constrain a model of the impact structure. The modeled complex impact structure has a 5 to 6 km diameter and is totally buried by sediments. This burial has occurred in &lt;0.9 Ma, which is challenging but not incompatible considering the erosion rates in the area and the pre-existing neighboring topography.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2284-2302"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70218","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"John William Larimer (1939–2026)","authors":"Herbert Palme,&nbsp;Bruce Fegley","doi":"10.1111/maps.70209","DOIUrl":"https://doi.org/10.1111/maps.70209","url":null,"abstract":"&lt;p&gt;Professor John W. (Jack) Larimer passed away on January 22, 2026, at the age of 86. He is survived by his wife, Sally, and two children, Natasha and Jesse.&lt;/p&gt;&lt;p&gt;Jack Larimer's work in the late 1960s was simply put, phenomenal. It set the standard and direction of research in the field of cosmochemistry for about the next 60 years. That is up until today. We are still concerned with problems Jack Larimer identified and tried to solve, and his papers in 1967 by himself, and in 1967 and 1970 with Edward Anders, his postdoctoral supervisor at the University of Chicago.&lt;/p&gt;&lt;p&gt;Larimer attended Lehigh University in Bethlehem, Pennsylvania, on a football scholarship. There he developed an enduring interest in geology and meteorites and earned his bachelor's (&lt;span&gt;1962&lt;/span&gt;), master's (1963), and doctoral degrees (1966). While still at Lehigh, he published his first paper on geological thermodynamics (Larimer, &lt;span&gt;1962&lt;/span&gt;), a study of subsolidus phase relations in the lead–bismuth–selenium system that foreshadowed his long engagement with experimental and computational thermodynamics.&lt;/p&gt;&lt;p&gt;Larimer's doctoral thesis combined one-atmosphere gas-mixing experiments with thermodynamic calculations to determine how oxygen fugacity (fO&lt;sub&gt;2&lt;/sub&gt;) and temperature control the stability of CaS (oldhamite), characteristic of enstatite chondrites, and of FeO-bearing olivine and orthopyroxene, the dominant minerals in ordinary chondrites. This work was an early application to meteorites of the gas-mixing method for fO&lt;sub&gt;2&lt;/sub&gt; control.&lt;/p&gt;&lt;p&gt;From 1966 to 1969, Larimer was a postdoctoral fellow with Edward Anders at the University of Chicago. In 1969, he joined the geology faculty of Arizona State University, where he spent the remainder of his career. He served for many years as associate director of the Buseck Center for Meteorite Studies, represented ASU at the Universities Space Research Association (1979–2000), and contributed widely to university service through Faculty Senate work and numerous curriculum and search committees.&lt;/p&gt;&lt;p&gt;Larimer is best known for the equilibrium condensation calculations that became a cornerstone of modern cosmochemistry. His ground-breaking 1967 paper (Larimer, &lt;span&gt;1967&lt;/span&gt;) gives the first comprehensive treatment of major, minor, and trace element condensation from a solar-composition gas. Drawing on thermodynamic data and methods familiar from metallurgy, he developed what is now widely termed the “condensation sequence” and established a quantitative basis for linking meteoritic compositions to nebular conditions. His 1967 paper addressed key physical and chemical processes, including fractional condensation, diffusion in mineral grains, and trace element solid solution in major condensate phases. Almost all the essential features of nebular chemistry are presented in this one paper.&lt;/p&gt;&lt;p&gt;Larimer subsequently wrote a number of important and influential papers dealing with applications of thermodynamic cal","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2406-2408"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70209","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bolide light curve systematics from 75 recovered meteorites","authors":"Peter Jenniskens,&nbsp;Stuart Pilorz,&nbsp;Darrel Robertson,&nbsp;Eric C. Stern","doi":"10.1111/maps.70203","DOIUrl":"https://doi.org/10.1111/maps.70203","url":null,"abstract":"<p>How does the energy deposition profile (light curve), deceleration, and penetration depth in Earth's atmosphere depend on asteroid composition and meteorite type? Here, we present the light curve and velocity profile of 75 bolides from camera-documented meteorite falls. The light curves as a function of altitude generally develop in the following seven phases: Phase (1) an initial rapid brightening; (2) a gradual increase that sometimes shows periodic brightness variations; (3) an onset and rapid increase of brightness until reaching a plateau; (4) a plateau with occasionally chirping brightness oscillations; (5) flares that result in fragments in the meteor wake; (6) an end flare of sometimes different color; and (7) ongoing ablation and fragmentation until dark flight. These seven phases are interpreted as resulting from solid bodies that cause early brightness oscillations from meteoroid spin, a plateau because of melting and reaching melting equilibrium, chirping oscillations due to plasma instabilities, flares due to fragmentations along fractures from dynamic pressure and thermal stress, and an end flare when the surviving back of the meteoroid explodes. This paper discusses the systematics of how the phase heights depend on entry speed, entry angle, initial mass, and meteorite type. The dynamic pressures during the onset of fragmentation and the end flare correlate with the tensile strength of the recovered meteorites. The results have implications for Planetary Defense when anticipating the energy deposition curve of small solid-body airbursting asteroid impacts like <i>Chelyabinsk</i>.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2351-2392"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygen isotope variability in the IIIAB iron meteorites and their relationship to main group pallasites","authors":"R. J. Windmill,&nbsp;I. A. Franchi,&nbsp;X. Zhao,&nbsp;R. C. Greenwood,&nbsp;M. Anand","doi":"10.1111/maps.70210","DOIUrl":"https://doi.org/10.1111/maps.70210","url":null,"abstract":"<p>The light element distribution in planetary cores and the processes driving core evolution in rocky planets are poorly understood. Magmatic iron meteorites are samples from the cores of ancient embryonic planetesimals and therefore provide a window into the processes governing core evolution. We performed high precision oxygen isotope analyses on chromite from IIIAB iron meteorites to investigate the oxygen isotopic evolution across a protoplanetary core using laser-assisted fluorination. We identify three unexpected and hitherto unreported discrete isotopic subgroups within the IIIAB chemical group and discuss possible causes for their existence. The most likely explanation is that they may be sampling multiple parent bodies, either completely unrelated or mixed during an impact. This would have significant implications for the use of the chemical classification scheme for iron meteorites as well as models for IIIAB core evolution. Second, that they may be evidence that oxygen mobility across the core was controlled by diffusion. If this is the case, they may represent homogenized melt pools in a wider core context, recording oxygen diffusion into a planetary core, which could help explain the density deficit observed in Earth's core. Third, we discuss whether core rain out through a heterogeneous IIIAB mantle and inefficient mixing in the core could explain the isotopic results. Finally, we compare these IIIAB oxygen isotopic signatures to published data for main group pallasite minerals and conclude that the meteorite groups cannot be from a common parent body, answering a long-standing question in meteoritical science.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2393-2405"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70210","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nature, origin, and phosphorylation potential of the phosphorus/sulfur-bearing nanoscale multiphasic assemblages in the CM chondrites Murchison and Murray","authors":"Valentine Megevand,&nbsp;Sylvain Bernard,&nbsp;Corentin Le Guillou,&nbsp;Roberto Conconi,&nbsp;François Guyot","doi":"10.1111/maps.70214","DOIUrl":"https://doi.org/10.1111/maps.70214","url":null,"abstract":"<p>Carbonaceous chondrites contain phosphorus, whose speciation and thus history remain to be investigated. Phosphorus/sulfur-bearing assemblages have been reported in carbonaceous CM chondrites, but there is no consensus about their exact compositions and origins. Here, we present submicrometer-scale investigations by analytical transmission electron microscopy of phosphorus/sulfur-bearing assemblages from the CM chondrites Murray and Murchison. Results indicate that, in CM chondrites, phosphorus associated with sulfides occurs under distinct oxidation states. In Murray, we identified a pyrrhotite–schreibersite nanocrystalline assemblage associated with carlsbergite and chromite. Its reduced nature and petrographic context are indicative of a nebular formation mechanism, possibly through kamacite sulfidation. In contrast, Murchison contains nanocrystalline pentlandite assemblages associated with carlsbergite and likely with phosphate phases that we interpret as being produced via interactions with an oxidizing fluid under asteroidal conditions. Thermodynamic modeling suggests that such complex assemblages hosting reactive forms of both phosphorus and nitrogen could promote the synthesis of activated phosphate species such as diamidophosphate, an efficient phosphorylation reagent, thereby underscoring their potential prebiotic significance.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2303-2335"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70214","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructural evidence for multiple generations of sulfide precipitation and impact-induced thermal alteration under acidic conditions on Asteroid Ryugu","authors":"M. C. Benner,&nbsp;B. S. Prince,&nbsp;D. L. Schrader,&nbsp;T. J. Zega","doi":"10.1111/maps.70212","DOIUrl":"https://doi.org/10.1111/maps.70212","url":null,"abstract":"<p>Here we report on the microstructure and chemistry of sulfide minerals returned from asteroid (162173) Ryugu. We identify a unique sulfide population in particle A0016 composed of violarite (FeNi₂S₄), pyrite (FeS₂), chalcopyrite (CuFeS₂), pyrrhotite (Fe_1-xS), and pentlandite ([Fe,Ni]₉S₈). Violarite, pyrrhotite, and pyrite reveal evidence of formation from a fluid including porosity, phyllosilicate inclusions, and gaps along grain boundaries due to volume change. Violarite grains are polycrystalline with spatially correlated Ni and Co enrichments and contain pyrrhotite lamellae measuring 100s nanometers across. Pyrite assemblages are polycrystalline with spatially anticorrelated Ni and Co enrichments. In comparison, the chalcopyrite grain is a compositionally homogeneous single crystal spatially associated with rutile (TiO₂). The data suggest that particle A0016 experienced multiple generations of fluid flow. The first generation of fluid flow occurred at low temperatures (25 to 100 °C) under alkaline (pH &gt; 8) conditions, leading to the precipitation of pyrrhotite and pentlandite. In comparison, the second generation of fluid flow was acidic (pH &lt; 6.5) and reducing (−0.14 ≤ Eh ≤ −0.36) at elevated temperatures (230 to 300 °C), leading to formation of pyrite, violarite, and chalcopyrite. The elevated temperatures required to produce this sulfide population are consistent with heating from an impact on Ryugu's parent body.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2201-2217"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70212","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetization records of terrestrial weathering in the Sericho pallasite","authors":"Ji-In Jung,&nbsp;Sophia Gaal,&nbsp;Sonia M. Tikoo,&nbsp;Ethan Lopes,&nbsp;Jonathan Mells,&nbsp;Dale H. Burns,&nbsp;Robert G. Hatfield","doi":"10.1111/maps.70217","DOIUrl":"https://doi.org/10.1111/maps.70217","url":null,"abstract":"<p>Paleomagnetic investigations of pallasites are important for understanding the dynamo histories of their parent bodies and the formation mechanisms of these meteorites themselves. To understand the temporal evolution of pallasite parent-body dynamos, additional paleomagnetic studies of new meteorites are needed. However, such efforts require a thorough understanding of magnetic carriers and recording properties of pallasites to ensure that any observed remanence reflects primary magnetic records. Here, we investigate olivine grains in the main group Sericho pallasite to evaluate their suitability for paleomagnetic studies. Electron microscopy, combined with rock magnetic analyses, reveals colloidal, euhedral magnetite grains hosted within iron oxide veins (likely goethite) formed during post-fall aqueous alteration within our Sericho sample. All results indicate that secondary mineral phases dominate the remanence, precluding reliable recovery of primary parent-body magnetic fields. Our study presents a cautionary tale about how different samples of the same meteorite can experience heterogeneous degrees of weathering, ranging from effectively pristine to so altered that paleomagnetic studies probing parent body processes cannot be conducted. As such, meteorites must be carefully scrutinized on an individual-sample basis before paleomagnetic studies to ensure high-fidelity results.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2336-2350"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystallization of dmisteinbergite (hexagonal CaAl2Si2O8) from type B CAI analog melt","authors":"Yasuaki Tsuruoka,&nbsp;Hideto Yoshida,&nbsp;Yuki Inoue,&nbsp;Daiki Yamamoto,&nbsp;Hiroyuki Kagi,&nbsp;Akira Miyake,&nbsp;Shogo Tachibana","doi":"10.1111/maps.70213","DOIUrl":"https://doi.org/10.1111/maps.70213","url":null,"abstract":"<p>Dmisteinbergite is a metastable polymorph of CaAl₂Si₂O₈, which has been found in calcium−aluminum-rich inclusions (CAIs) in chondrites, although anorthite is the predominant CaAl₂Si₂O₈ phase in natural type B CAIs. The occurrence/absence of igneous dmisteinbergite would put tighter constraints on the thermal history of CAIs. However, little attention has been paid for crystallization of dmisteinbergite in CAI melts even though its kinetically controlled crystallization (i.e., crystallization from a supercooled melt) has been proposed. In this study, we conducted dynamic crystallization experiments on CAI analogs in the presence of low-pressure hydrogen gas (1–10 Pa) to simulate the formation of igneous CAIs and to understand crystallization behavior of CaAl₂Si₂O₈ phases. Dmisteinbergite was found in samples cooled at rates of 1–20 °C h⁻¹, while anorthite was found in samples cooled at 5 °C h⁻¹, suggesting that the slow cooling (likely slower than on the order of 1 °C h⁻¹) might promote the formation of anorthite. Because the slow cooling rates during the final stage of crystallization of CAIs likely reflect conditions approaching the background temperature of CAI-forming regions, CaAl₂Si₂O₈ phases in type B CAIs could constrain the thermal history and formation environment of those regions.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":"2258-2268"},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laurence E. Nyquist (1939–2026)","authors":"Connie Nyquist,&nbsp;Donald D. Bogard,&nbsp;Gregory F. Herzog,&nbsp;Jisun Park","doi":"10.1111/maps.70227","DOIUrl":"https://doi.org/10.1111/maps.70227","url":null,"abstract":"<p>Larry Nyquist was born in Tracy, Minnesota (population ~3000), and began his education in a one-room schoolhouse. His interest in the solar system started as a young boy when he, his brother, and father would lie in the grass, and his father would point out the stars and give their names. He graduated with a major in physics and mathematics from Macalester College in 1961 and went on to earn MS (1963) and PhD (1969) degrees in physics from the U. Minnesota. Larry had started working on his PhD when his mentor, Peter Signer, decided to move from U. Minnesota to the Swiss Federal Institute of Technology in Zurich. Larry went with him and carried out the work with noble gases in meteorites that was the subject of his PhD thesis. In the year that Larry got his PhD degree, the Apollo 11 mission returned the first lunar samples, and shortly thereafter, Paul Gast became the director of the Planetary Science Division at the Johnson Space Center. Larry was one of his first hires. JSC had recently acquired a new solid-state mass spectrometer, and Larry moved into that field. In a career at JSC that lasted nearly 50 years, he produced valuable research on radiometric age dating and isotope geochemistry employing a variety of elements and in collaboration with many coauthors. In 1982, he was elected a Fellow of the Meteoritical Society in recognition of his contributions to planetary chronology and isotopic systematics; in 2014, he received the NASA Exceptional Service Medal for significant sustained performance characterized by unusual initiative or creative ability; and in 2024, he was given the Eugene Shoemaker Distinguished Scientist medal for his continuing contributions to lunar research.</p><p>Collaborating with Larry was a pleasure. His motto was, “Follow the data,” and in so doing, he was knowledgeable, careful, attentive to detail, and ready to go out-of-the-box when we got stuck. No matter how busy or stressed things got, he took the time to listen, lift others up, and show kindness and tact. Main Belt Asteroid 6625 Nyquist, discovered in 1981, is named after him.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"61 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.70227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}