Volcanoes Pt. III + IV Flashcards
what chemical that has greatest impacts on climate on shorter time-scales?
sulphur
where do very large eruptions (duration of eruption also matters) inject aerosols and ash?
-stratosphere (no weather to remove material unlike trophospere)
sulfur that enter the stratosphere does what?
reacts with water and form H2SO4 droplets which are highly reflective and scatter and absorb incoming solar radiation so troposphere cools but stratopshere warms
increases in optical depth after volcano eruption indicated what?
global atmospheric circulation of aerosols so eruption in the tropics are more likely to have global impacts on climate
the different variables that affect impact eruption makes on climate
-time of year
-location
-weather patterns
-volatile content
-eruption style/length
Volcanic Explosivity Index (VEI) is a scale that describes what?
the size of explosive volcanic eruptions based on magnitude and intensity
basaltic eruptions are often are much more sulfur-rich than ____ ones so can have major effects even if they aren’t as explosive
felsic
multiple closely spaced eruptions could cause what climate effect?
-more persistent climate perturbation because cooling may be extended (climate feedbacks)
LIPS stands for what?
large igneous provinces (aka continental flood basalts)
LIPS represent times when large volumes of mostly ___ magmas were generated/extruded onto landscape. where do they form?
-mafic magmas
-form independent of plate setting (in oceans, continents, within plates or between them; at hot spots/mantle plumes)
short term climate effects
cooling (ozone depletion, acid rain, cooling)
long term climate effects
global warming (CO2)
climatic issues beyond cooling/warming from LIPS
-ocean acidification
-ocean anoxia
-acid rain
-gas and impacts block light - photosynthetic shutdown
LIPS of mass extinctions
1)devonian: Viluy LIPS
2)Permian: Siberian Traps LIPS
3)Triassic: CAMP LIP
4) creat:Deccan Traps LIP
(maybe Ordovician)
LIPS can explain many of the distinctive features commonly seen in the geologic records of most major extinctions:
- Loss of carbonate deposition in oceans (re: acidification)
- Negative carbon isotopic excursions (thermogenic greenhouse gases?) and
persistent instability - Spikes in metal deposition
- Other isotopic excursions (i.e., sulfur, mercury, nitrogen)
Long term carbon cycling: silicate-carbonate weathering cycle
carbonate–silicate geochemical cycle, also known as the inorganic carbon cycle, describes the long-term transformation of silicate rocks to carbonate rocks by weathering and sedimentation, and the transformation of carbonate rocks back into silicate rocks by metamorphism and volcanism.
what is glacial pump? (reverse now -> volcanism caused by climate change)
volcanism increases in response to deglaciation and isostatic rebound
volcanoes don’t produce smoke bu ____
ash
detailed mapping of ____ is key to determing eruption freq & magnitude (determines VEI). produces which type of map?
tephra
isopach maps (establishing eruption histories)
signs that magma is moving but at deep depths
-elevated CO2 emissions
-deep long period earthquale
-aseismic inflation
-changes in water chmistry and thermal output
signs that magma is moving but at shallow depths
-ground deformation
-Volcano-tectonic seismicity
-ground cracking/glacial melting
-sulfur degassing
-H2S to SO2 change emssions
-phreatic explosions
canada doesn’t have what?
volcanic monitoring programs despite being volcanic country
monitoring equipment includes what?
seismometers, tiltmers, GPS, gas monitoring stations, airborne surveys, remote sensing from space/aircraft
can we predict eruptions
swarms indicate moving magma
response to volcanoes
1) escape routes
2) early warming systems (sirens)
3) downloadable maps
