b'Education matters magnetic microspherules in YD sedimentssigni\x1dcantly larger magnetic fractions, having been successful, this early failuresigni\x1dcantly reducing the ratio of is still cited by critics today as fatal tomicrospherule candidates to non-the hypothesis. This study sought to testcandidate grains. The aliquot sizes the claims of proponents regarding theexamined during the failed replication reasons for an early failure to replicatewere found to produce highly variable, a particular line of evidence, magneticand therefore unreliable results when microspherules, using experimentalcalculating the number of spherules per methods. Following the early failurekg in each sample. The inappropriate to replicate, proponents published arequirement for perfect sphericity detailed study successfully replicatingimposed by the failed replication the evidence at multiple locationswas found to signi\x1dcantly reduce the and o\x1eering explanations for why thenumber of spherule candidates in replication had failed, which informed theeach sample and would have caused methodological basis of this study. spherules formed during the impact to have been excluded from their Thus, using experimental methods, Ianalysis. Finally, SEM-EDS was found to investigated the e\x1eects of insu\x1ccientbe an essential method for con\x1drming aliquots of the sample and the exclusionwhether a spherule candidate was it is thought that Earth encounteredof subspherical candidates, but alsoindeed formed during an impact a particularly violent meteor showervariations in the magnetic separationevent. Overall, this study found that at the YD onset, resulting in manyprotocols used by the relevant studies.inappropriate modi\x1dcations of the smaller-scale impacts and airburstsThe utility of scanning electronprotocols of the original study were the over much of the world within a shortmicroscopy and energy-dispersivelikely cause of the failed replication. The time. While controversial, recent reviewsX-ray spectroscopy (SEM-EDS) forresults a\x1crm the speci\x1dc claims made have determined that the YD impactcharacterising the morphological andby proponents, and the notion that the hypothesis was prematurely rejectedgeochemical attributes of microspheruleYD impact hypothesis has indeed been after early attempts to replicate key linescandidates to determine how they wereprematurely rejected.of evidence were unsuccessful. formed was also a major focus.Despite every subsequent attempt toMagnetic separation protocols usedMarc is currently undertaking a PhD in replicate elevated concentrations ofduring the failed replication producedgeoarchaeology at Flinders University.Participants in CAGE 2023.35 PREVIEW DECEMBER 2023'