1. Formed of a single shield volcano, Palawa caldera on the Maui Nui
Island of Lana‘i
Formed of a single shield volcano, Palawa caldera on the Maui Nui
The Lana‘i volcano reached the subaerial sheild stage, has a single volcanic rock member
Lana‘i Member, tholeiitic basalt, 1.46 to 0.78 Ma
pahoehoe and a‘ā, and and spatter cones on the rift zones
caldera partly filled by lava, but is still visible
three rift zones
grabens along rift zones
This volcano also has has marine deposits, evidence for higher stands of the sea

2. Island of Lana‘i

3. Pacific Ocean

4. Pacific Ocean
Lanai Volcano Palawa caldera
Rift zones

5. Reef coral and basalt boulders deposits resting ~conformably
on basalt flows, ~100 m above sea level, south coast of Lana‘i -

6. Lanai slumped into sea on southwest: sea cliff exposing faults

7. Lāna‘i, volcanic ridge line is the old caldera rim

8. Island of Kaho‘olawe

9. Island of Kaho‘olawe Formed of a single shield volcano
Shield Stage, Lower Member (age unknown)
caldera is present but filled in, ~5 km diameter
typical shield lavas, tholeiitic basalt
later shield-stage lavas have high silica (similar to Ko‘olau)
source rock for adzes found all over Hawai‘i
Postshield Stage, Upper Member, ~1.0 Ma
small extent, include top part of caldera filling lavas
hawaiite
Rejuvenation Stage Vents?
Youngest vents cut alluvium, but are tholeiitic (!); found at top of sea cliff
Water problems--shallow wells yield brackish water
in rain shadow of Maui; also a low island
little vegetation--overgrazed (had been used as a ranch)
soil erosion by wind
Eastern part of volcano is missing--landslide?
No debris, but eruptions from SW rift of East Maui may bury deposits

10. Kaholawee Volcano Caldera and rift zones
Pacific Ocean

11. Island of Kaho‘olawe

12. Pacific Ocean

13. Sea arches and sea cliffs exposing caldera-filling lavas