Hawaiian Submarine Volcanism
November 1, 2011
Mary Tardona GG 711
Stages of Hawaiian Volcanoes:
• Typically, three main stages:
– Pre‐shield
– Shield
– Post‐shield
• Sometimes followed by:
– Rejuvenation Stage
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Classification
Alk-SiO2
LeBas
6
LeBas
Basanite
5.5
Macdonald
Hawaiite
Macdonald
5
J2-380_XRF
Na2O + K2O wt%
4.5
J2-381_XRF
Alkali Basalt
J2-551_XRF
4
J2-556_XRF
3.5
J2-557_XRF
3
J2-560_XRF
Basaltic Andesite
2.5
J2-380_glass
J2-381_glass
2
J2-556_glass
Tholeiitic Basalt
1.5
44.5
J2-557_glass
45.5
46.5
47.5
48.5
49.5
50.5
51.5
52.5
53.5
SiO2 wt %
Pre‐shield
•
•
•
•
Submarine Alkalic Lava
Lower T
Low Volume
• Loihi ~1,700 km3
• Kilauea ~3,350 km3
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Shield Building
• Submarine ‐‐ Subaerial
• Tholeiitic
• Higher T
– High eruption rate
• Highest Volume – >95% • Kilauea Post‐shield • Alkalic “Cap”
• Low T – Lower eruption rate
• Slightly more explosive
– Higher viscosity – Lava contains slightly more gas
– More crystal‐rich GG 711, Fall 2011, Lect. 11, Mary Tardona
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Rejuvenation Stage
Na2O + K2O
• 500,000 – 3 million years after main eruption
• Not continuous, can have gaps of up to 1,000 years between eruptions
• More explosive
• Monogenetic
• Low Volume
• Highly alkalic lavas
alkali SiO2
LeBas
6
5.5
LeBas
Basanite
Macdonald
Hawaiite
Macdonald
5
J2-380_XRF
4.5
J2-381_XRF
4
J2-551_XRF
J2-556_XRF
3.5
J2-557_XRF
3
J2-560_XRF
J2-380_glass
2.5
J2-381_glass
2
1.5
44.5
J2-556_glass
J2-557_glass
46.5
48.5
50.5
52.5
54.5
SiO2 wt %
Rejuvenation Stage
– Honolulu Volcanics
– East Maui Volcano
GG 711, Fall 2011, Lect. 11, Mary Tardona
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PreshieldShield BuildingPostshield
Alkalic  Tholeiitic Alkalic
Waianae Volcano
Alk-SiO2
Lualualei
7.50
Kamaileunu
6.50
Palehua
Na2O+K2O
5.50
labas
4.50
MacDonald
3.50
Diamond
Head
2.50
1.50
45.00
47.00
49.00
51.00
53.00
SiO2 wt %
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Hawaiian Submarine Volcanism
• Early Stages
• Rift Zone
• Submarine rejuvenation
Preshield and Early Shield Stage Submarine Hawaiian Volcanism
• Loihi
– Transitional‐
tholeiitic lavas
– 1996 eruption
• Shallow earthquakes
– Few 0‐5 km
– mostly around 8 km
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Preshield and Early Shield Stage Submarine Hawaiian Volcanism
• Loihi
– 1996 eruption
•
•
•
•
•
Pele’s pit
Collapsed location of great hydrothermal activity
600m diameter
Bottom 300m below original surface
Exposed massive columnar jointed lavas
Preshield and Early Shield Stage Submarine Hawaiian Volcanism
• Loihi
– 1996 eruption
• Intense hydrothermal plumes
•
•
0.2‐0.25°C anomalies up to 8km away
*MOR eruptions typically have ~.02‐0.1°C anomalies (though few have been recorded as higher)
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Preshield and Early Shield Stage Submarine Hawaiian Volcanism
• Loihi
– 1996 eruption
• Vent fields‐
Temperatures up to 77°C
• Diffuse venting
– although 13 m wide fissures venting large volumes of water in the south rift vent area
• High Temp sulfide minerals found
– Indicate vent waters at temperatures of 250°C
Preshield and Early Shield Stage Submarine Hawaiian Volcanism
• Loihi
– 1996 eruption
•
•
•
•
•
Dense lava
Pillows
Sheet flow
Pele’s hair
Limu o’ Pele
M.Garcia
*Figures and Loihi data taken from SOEST’s Hawaii’s Center for Volcanology Website
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Rift Zone Volcanism : Puna Ridge
• Tholeiites
• Flow fields
– Sheet flows
– Lobate flows
– Pillow flows
• Distinguished from lobate flows by extrusion marks on surfaces
– Found at all depths along the ridge
Rift Zone Volcanism : Puna Ridge
• Pillow Ridges
– Pillow flows along fissures
– Up to 500 m to a few km long, few tens of meters wide
– Located at the shallow end of Puna Ridge (up to <2000m)
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Rift Zone Volcanism : Puna Ridge
• Cones
– Largest cones (heights >100m) have flat tops and craters
• Flanks covered in rubble and hyaloclastites
– Possibly indicative of phreomagmatic
eruption
– Smaller cones
• Height <100m
• Pointed tops
• Elongate and tubular pillows on flanks
• Deep craters
– Draining of magma after eruption ceased
• Columnar jointed lavas
– Indicate cooling of meters‐thick flows – (Smith et al., figure 6)
Rift Zone Volcanism : Puna Ridge
• Terraces
– Near circular, flat topped, Several km wide, few hundred meters high
– High Volume
• 0.1‐1.0 km3
– Two Main types: • Slightly domed tops
– Inflation features
• Terraces with at least one summit crater
– Possibly tube fed *Lister and Dellar Formulation*
• Skylights • Happens on the slow spreading Mid‐Atlantic Ridge
– Possibly Dike fed GG 711, Fall 2011, Lect. 11, Mary Tardona
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Rift Zone Volcanism : Puna Ridge
• Stair Stepping Terraces (2300‐2500m)
– Increase in volume down‐rift
– A down‐rift terrace down has radiating tube network from crater
• Lava flowed out onto horizontal summit from the crater
– Numerous craters and collapse features
• Deep step terraces (3700‐4100m)
– Pillow, Lobate, and sheet flow cover
Rift Zone Volcanism : Puna Ridge
• Two main trends in morphology vs. depth
– Two fissures on crest of ridge • Only at shallow depths above 1100m
– Cones at depths of ~600 ‐ ~2200m
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Submarine Rejuvenate Volcanism • Alkalic
• Cones
– Pillow lava • Base (~890m)
• Near top of one cone (~430m)
– Talus‐like blocky lavas at summit (~500m)
• Effusive eruptions of higher viscosity lavas
– Vesicle and crystal rich
Submarine Rejuvenate Volcanism • Cones
– Shallower cones (~100‐
300m)
• Fine bedded/cross bedded ash deposits – Fine grained ash – Volcanic breccia
– Grain size increasing toward top of cones • Surtseyan‐style, explosive eruption
GG 711, Fall 2011, Lect. 11, Mary Tardona
Surtsey, NOAA 1963
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Submarine Rejuvenate Volcanism • Flank of Diamond Head:
•
From 562m to 494m deep
Submarine Rejuvenate Volcanism • Up the flank of Diamond Head
– Finely layered volcaniclastic
deposits (panel c)
– Volcaniclastic
sediments draped over pillows (panel d)
GG 711, Fall 2011, Lect. 11, Mary Tardona
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Hawaiian submarine volcanics are dynamic
• Early Shield stage • Ridge
– Pillow flows
– Sheet flow
– Pele’s hair
– Limu o’ Pele
– Pit craters
• Rejuvenations
– Pillow flows
– Lobate flows
– Fissures and effusive flows
– Cones
– Terraces
– Pillow flows
– Volcaniclastics
– Cones
• craters
– Lava tubes
GG 711, Fall 2011, Lect. 11, Mary Tardona
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