Received 1 April 2008

IODP Proposal Cover Sheet
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RevisedAddendum

716-Full2
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Title: Drowned corals reefs around Hawaii: a unique archive of sea-level, climate change and reef
response over the last 500 kyr
Proponent(s): J. M. Webster, A. C. Ravelo, C. Gallup, D. A. Clague, N. Allison, J. C. Braga, J. Chiang, C.
Fletcher, E. Grossman, Y. Iryu, , J. Pandolfi, W. Renema, Y. Yokoyama, C. Vasconcelos, R.
Warthmann, S. P. Templer
Keywords: climate change, sea level, coral reef response, geomicrobiology,(5 or less) central Pacific,

Area:

CentralPacific
Ocean; HawaiiContact Information:
Contact Person:
Department:
Organization:
AddressTel.:
E-mail:Dr. Jody M. Webster
School of Earth and Environmental Sciences
James Cook University
School of Earth and Environmental Sciences+617 4781 5283
jody.webster@jcu.edu.au

Fax: +617 4725 1501

Permission to post abstract on IODP Web site:

YesNo

Abstract: (400 words or less)Our understanding of the links and mechanisms that control eustatic sea-level and global climate changes has beensignificantly hampered by a lack of appropriate fossil coral records over the last 500 kyr - particularly into and outof the glacial periods. We propose to address this problem directly by drilling a unique succession of drowned coral
reefs around Hawaii now at -134 to -1155 m. Abundant observational and numerical modeling data indicate that theinternal stratigraphy and tops of these reefs are highly sensitive to sea-level and climate changes, thereby providing
a firm template with which to conduct these operations. As a direct result of Hawaii’s rapid (2.5-2.6/kyr) but nearly
constant subsidence, a thick (100-200 m) expanded sequence of shallow coral reef dominated facies is preserved
within the reefs. These reefs span important periods in Earth climate history, either not available or highly
condensed on stable (Great Barrier Reef, Tahiti) and uplifted margins (Papua New Guinea, Barbados) due to a lackof accommodation space and/or unfavorable shelf morphology. Specifically, these data show that the reefs grew(for ~90-100 kyrs, albeit episodically) into, during and out of the majority of the last five to six glacial cycles.
Therefore, scientific drilling through these reefs will generate a new record of sea-level and associated climate
variability during several controversial and poorly understood periods over the last 500 kyr. The project has four
major objectives. First, to constrain the timing, rate, and amplitude of sea-level variability over the last 500 kyr
allowing a definitive test of Milankovitch climate theory and an assessment of controversial abrupt sea level events(meltwater pulses) that occur on suborbital frequencies associated with events occurring in the extra-tropics (i.e.
Dansgaard/Oeschger ice core temperature Events, and related Heinrich ice rafted debris Events in N. Atlantic
sediment cores). Second, to investigate processes that determine changes in mean climate and high-frequency(seasonal-interannual) climate variability using high-resolution coral proxy data from times with different climate
forcing boundary conditions (e.g. ice sheet size, pCO2, solar forcing) over the last 500 kyr. Third, to determine theresponse of coral reef systems to abrupt sea-level and climate changes, test sedimentary models of reef evolution as
well as ecologic theories of coral reef resilience and to establish the role of microbial communities in reef building.
And fourth, to refine the variation through space and time of the subsidence of Hawaii and contribute tounderstanding the volcanic evolution of the island.

716-Full2
Scientific Objectives: (250 words or less)
1. To define the nature of sea level-change in the central Pacific over the last 500 kyr, we will construct a new, more
complete sea level curve from the drowned Hawaiian reefs that will allow: a) more detailed testing of Milankovitch
climate theory predictions and; b) improved constraints on millennial-scale sea-level changes over the last 500 kyr.
2. To identify critical processes that determine paleoclimate variability of the central Pacific over the last 500 kyr, wewill: (a) reconstruct the mean and seasonal/interannual climate variability from massive coral samples; and (b) use
these records to investigate how high latitude climate (e.g., ice sheet volume), pCO2, and seasonal solar radiation
impact subtropical Pacific climate. This approach can be used to test theoretical predictions of climate response andsensitivity to changes in boundary conditions and climate forcing.
3. To establish the geologic and biologic response of coral reef systems to abrupt sea-level and climate changes, wewill: (a) establish the detailed stratigraphic and geomorphic evolution of the reefs in response to these changes; (b)test ecologic theories about coral reef resilience and vulnerability to extreme, repeated environmental stress overinterglacial/glacial to millennial time scales; and (c) establish the nature of living and ancient microbial communities
in the reefs and their role in reef building.
4. To elucidate the subsidence and volcanic history of Hawaii, we will: (a) refine the variation through space and timeof the subsidence of Hawaii, and; (b) improve the understanding of the volcanic evolution of the island.
Please describe below any non-standard measurements technology needed to achieve the proposed scientific objectives.
NA

Proposed Sites:
Site
Name

Position

Water
Depth(m)Penetration (m)Sed

Bsm Total

Brief Site-specific Objectives

Primary
KON-01A
KAW-03A
KAW-04A
KAW-06A
KAW-07A
MAH-01A
MAH-02A
KOH-01A
KOH-02A
HIL-01A
HIL-05A

19.600341N, -156.010975W
20.018587N, -155.866458W
19.995815N, -156.032933W
20.036417N, -156.065696W
20.137266N, -156.079341W
20.055411N, -156.189697W
20.050262N, -156.192035W
20.290268N, -155.651218W
20.273958N, -155.490294W
19.758805N, -154.985708W
19.876999N,-154.939618W-145-154-419-737-988-1102-1154-410-930-134-402

14014014014014014014014014014014010101010101010101010110150150150150150150150150150150150

H1d reef that spans MIS 1-5 (leeward, dry)H1d reef that spans MIS 1-5 (leeward, dry)H2d reef that spans MIS 6-7 (leeward, dry)H4 reef that spans MIS 8-9 (leeward, dry)H6 reef that spans MIS 10-11 (leeward, dry)H8a reef that spans MIS 12-13 (leeward, dry)H8b reef that spans MIS 12-13 (leeward, dry))H2d reef that spans MIS 6-7 (windward, wet)
H7 reef that spans MIS 10-11 (windward, wet)
H1d reef that spans MIS 1-5 (windward, wet)
H2d reef that spans MIS 6-7 (windward, wet)

Alternate
KAW-01A
KAW-02A
KAW-05A
HIL-02A
HIL-03A
HIL-04A
MAH-03A
MAH-04A
MAH-05A

20.011332N, -155.848480W
20.017325N, -155.857206W
19.978715N, -156.029159W
19.883005N, -155.029932W
19.867141N, -154.973387W
19.869407N, -154.954576W
20.140405N, -156.238194W
20.065165N, -156.266945W
19.994893N, -156.229296W

-109
-131
-466
-271
-338
-354
-1213
-1234
-1289

140
140
140140140140140140140101010101010101010150150150150150150150150150

H1b reef that spans MIS 1-5 (leeward, dry)H1c reef that spans MIS 1-5 (leeward, dry)H2d reef that spans MIS 6-7 (leeward, dry)H2a reef that spans MIS 4?-7 (windward, wet)
H2b reef that spans MIS 5a?-7 (windward, wet)H2c reef that spans MIS 5a?-7 (windward, wet)
H9 reef that spans MIS 14-15? (leeward, dry)H10 reef that spans MIS 14-15? (leeward, dry)H11 reef that spans MIS 14-15? (leeward, dry)