Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
2
datasets available to search
ShareScore release 0.9.0
Dataset results
2 results for “cosmic spherule”
The oxygen isotope compositions of large numbers of small cosmic spherules: Implications for their sources and the isotopic composition of the upper atmosphere
<p>Cosmic spherules are micrometeorites that melt at high altitude as they enter Earth's atmosphere and their oxygen isotope compositions are partially or completely inherited from the upper atmosphere, depending on the heating experienced and the nature of their precursor materials. In this study, the <b>three oxygen isotope</b> compositions of 137 <b>cosmic spherules are</b> determined using 277 in-situ analyses by ion probe. Particles of each different type of cosmic spherule (scoriaceous, porphyritic, cryptocrystalline, barred, glass, calcium aluminium and titanium (CAT), G-type and I-type) in the diameter range ~52–480mm were analysed. The results confirm that the <b>three</b> oxygen isotope compositions of melted <b>micrometeorites</b> reflect a combination of their precursor composition, exchange with the atmosphere and mass fractionation owing to evaporation during entry heating. The data <b>appear to </b>reveal an increase in average δ<sup>18</sup>O values of silicate dominated (S-type) spherules in the series scoriaceous<porphyritic<barred<glass<CAT spherules (~20, 22, 25, 26 and 50‰) that is consistent with the evolution of oxygen isotopes by mass fractionation owing to increased average entry heating. The trend of δ<sup>17,18</sup>O is broadly parallel to the terrestrial fractionation line and thus suggests mass fractionation dominates changes in isotopic composition, with atmospheric exchange a less significant effect. The D<sup>17</sup>O values of spherules, therefore, are mostly preserved and suggest that ~80% of particles are related to the carbonaceous chondrites (CC) and are probably samples of C-type asteroids. The genetic relationships between different S-types can also be determined with scoriaceous, barred and cryptocrystalline spherules mostly having low D<sup>17</sup>O values <b>(≤0‰)</b> suggesting they are mainly derived from CC-like sources, whilst porphyritic mostly have positive D<sup>17</sup>O <b>(>0‰)</b> suggesting they are largely from ordinary chondrite (OC)-like sources related to S(IV)-type asteroids. Glassy and CAT-spherules have D<sup>17</sup>O values <b>indicating</b> they formed by intense entry heating of both CC and OC-like materials. I-type cosmic spherules have a narrow range of δ<sup>17</sup>O (~20–25‰) and δ<sup>18</sup>O (~38–48‰) values, with D<sup>17</sup>O (~0‰) <b>suggesting</b> their oxygen is obtained entirely from the Earth's atmosphere, albeit with significant mass fractionation owing to evaporation during entry heating. The observed range of δ<sup>18</sup>O with the size is suggested here to reflect entry angle with high values representing enhanced heating at high angle. Finally, G-type <b>cosmic spherules</b> have unexpected isotopic compositions suggesting little mass-fractionation from a CC-like source and are suggested to have sulphide-silicate precursors with relatively low melting temperatures. The results of this study provide a <b>vital assessment</b> of the <b>wider</b> population of extraterrestrial dust arriving <b>at the</b> Earth.</p>
The oxygen isotope compositions of large numbers of small cosmic spherules: Implications for their sources and the isotopic composition of the upper atmosphere
Open the record for dataset details and reuse information.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.