complex cinder cone eruptive sequence at o’neill crater, san francisco volcanic field
DESCRIPTION
Complex cinder cone eruptive sequence at O’Neill Crater, San Francisco Volcanic Field. Beth Schreck Northern Arizona University Mentor : Dr. Nancy Riggs. Introduction. The San Francisco Volcanic Field - 4,700 km 2 , over 600 volcanoes, 6 Ma to present Basaltic volcanism characteristics - PowerPoint PPT PresentationTRANSCRIPT
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Complex cinder cone eruptive sequence at O’Neill Crater,
San Francisco Volcanic FieldBeth Schreck
Northern Arizona UniversityMentor: Dr. Nancy Riggs
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IntroductionThe San Francisco Volcanic Field - 4,700 km2, over 600
volcanoes, 6 Ma to presentBasaltic volcanism characteristicsChanges in vent activityLava breaching and raftingPost-rafting activity
http://facweb.bhc.edu/academics/science/harwoodr/rhweb/thesis/index.htm
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Project GoalsO’Neill CraterWhy was there no
cone re-growth with further eruption?
Cinder cone models currently too simplistic
Cinder cones on Mars may have complex morphology
SP Crater photo courtesy WA Duffield
http://facweb.bhc.edu/academics/science/harwoodr/rhweb/thesis/FullThesis/index.htm
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DataData collection at
O’Neill CraterField workSamples collected
for thin section and Optically Stimulated Luminescence dating
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AnalysisThin sectionsRock crushing and lab workMappingGeologic principles
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ResultsGoal: eruptive
history of O’Neill crater
Chronology based on field analysis:
1. Cone-building stage
2. Continued eruption breached cone
3. Extrusion of dacite dome
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ResultsDacite dome
extrusion complexInjection of basaltic-
andesiteEruption triggered
dacite
basaltic-andesite
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ResultsBasaltic-andesite
eruption continuesEvidence from rocks
collectedQuestion still needs
to be answeredNew thin section
made
dacite fragment
basaltic-andesite
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AcknowledgmentsDr. Nancy RiggsNAU Space Grant ProgramMy family
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Questions?
http://facweb.bhc.edu/academics/science/harwoodr/rhweb/thesis/index.htm