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40lbsаThe submarine east rift zone on Haleakala extends about 135 km from the present shoreline. The shallower half of the rift is characterized by a smooth surface and numerous shoreline terraces, indicating that the region has subsided at least 2200 m and tipped towards the younger Hawaii Island to the south (Moore et al., 1990). Dredging the largest of these submerged terraces recovered corals that proved too old to reliably date using U-series analyses, suggesting that this prominent terrace is older (>500 thousand years) than the oldest terrace found around Hawaii. This once-subaerial surface is disrupted by a cluster of about 20 steep-sided cones (all shallower than about 1 km depth)-only one of which has been sampled. These cones are structurally distinct from subaerial cinder cones (they have no summit craters) and hence are thought to have formed below sea level. Below the deepest shoreline feature, the submarine rift zone resembles the rift zones of Kilauea, Mahukona, and Hilo Ridge with numerous flat-topped volcanic cones (Clague et al., 2000) and linear pillow ridges. In addition, two perched lava ponds were discovered in the Simrad dataset (Clague et al., 2000). These ponds, each several km across, formed above submarine eruptive fissures, built lava levees, and then drained (either back down the eruptive vent or out the side of the pond). Such features indicate that submarine eruptions can be voluminous enough to maintain lava ponds on the seafloor. Exploration of one of these features should confirm our morphologic analysis and provide information about the chemistry, eruptive temperature, and rheology of the lava that built such features.Radium sampler We request 9 12-hr Tiburon dives to sample and observe the structures of cones from between Kauai and Oahu, on the south flank of Kauai, and from a range of depths on NiihauТs northwest flank. The dives are designed to observe the range of volcanic landforms identified in the Simrad data in order to understand their formation, and to collect samples from as wide an area and as great a depth range as possible. Most of these dives are in water too deep for Pisces V operations, but several, selected to provide more complete spatial coverage, are <2,000 m deep. The ability of the ROV to cover more ground (up to 4 km at 3,500 m depth) than can be done during a typical Pisces dives (usually <1.5 km) makes the ROV the ideal vehicle to examine these large features. In shallower water, traverses can be even longer, or two dives may be accomplished in a single work day. The plan is to steam west from Honolulu about 4 hrs and dive in the channel between Oahu and Kauai, then to go to the south flank of Kauai (another 4 hr steam), and then on to NiihauТs west flank (another roughly 4-hr steam), then reverse the steps so that no transits monger than about 4 hrs are required. These samples will form the basis of a study of the geochemistry of rejuvenated stage lavas erupted near the center of the plume trace and should serve to define source region mixing near the margins of the Hawaiian plume.H. Gary Greene (Chief Scientist), Charlie Paull (Co-Chief Scientist), Dave Claque (Expedition Coordinator), Dave Caress, Bill Ussler, Norm Maher, Billy Moore (U. South Carolina), Jim Moore (USGS), D.J. Osborn, Jenny Paduan, Judith ConnorSuperposed on the sequence of reefs are a series of lava flows from several volcanoes, including a group of radial fissures (fissures not aligned along rift zones) that probably are part of Mauna Loa Volcano. At the western edge of the terrace, a submarine rift zone extends to the west. This rift zone is apparently part of a separate volcano named Mahukono Volcano (Clague and Moore, 1991)), not exposed above present sea level. Like other submarine rift zones, it is characterized by common flat-topped cones (Clague et al., 2000) and linear ramparts, but also by several complex, steep, smooth cones. This region is the key to understanding much of the history of Hawaii since the reefs provide timelines and the lava flows in the area come from Mahukona, Kohala, Mauna Kea, Mauna Loa, and Hualalai Volcanoes. Clague and Jim Moore did an entire HURL-funded program of Pisces V submersible dives in this region in 1988 and a modest dredging program the same year. However, the new MBARI Simrad bathymetric data highlight some key features that were unknown when the previous programs were completed. The models of reef formation suggest that details of the Pleistocene record of glacial-intergacial periods have been smoothed by time averaging. We hope to extract some of these details from the reef morphology and ages.
ALOHA 22.4500 158.0000 2 CTD, netsLeg 5: Iron mapping (May 22 - June 2)This Hawaii expedition is multidisciplinary in nature and the various legs reflect the diversity of interests and objectives. In addition to the geological objectives listed below, MBARI is also utilizing the transit times both to Hawaii (Leg 1) and back to Monterey (Leg 5).67-60 36.4530 122.7730 2 nets, CTDEquipment Description (include weight if available): Participants:GLORIA mapping around the Hawaiian Islands identified numerous cones and high-backscatter lava flows on the seafloor in four areas: 1) north of Oahu (the North Arch lavas described by Clague et al., 1990; Dixon et al., 1997; and Frey et al., 2000 and mapped by GLORIA and SeaBeam 2100 collected by Clague on a JAMSTEC cruise in 1999), 2) west of Oahu (mapped by GLORIA imagery and transit SeaBeam lines), 3) on the southeast flank of Kauai (mapped by Simrad EM300 by U.S. Geological Survey), and particularly 4) west of Niihau Island (mapped by Simrad EM300 by MBARI). The Simrad mapping of the region northwest of Niihau in 1998 revealed that the cones are large flat-topped cones with steep sides (Clague et al., 2000) despite their inferred alkalic compositions which contrast with the tholeiitic basalt compositions of similar cones along the rift zones. These cones are scattered over the seafloor from about 1500 to >5000 m depth and provide an unparalleled opportunity to understand degassing of magmas erupted at different depths or confining pressures. These cones have been interpreted to belong to the rejuvenated stage of volcanism and to correlate with the Kiekie Volcanics on Niihau (Clague, unpub. data), the Koloa Volcanics on Kauai (Clague and Dalrymple, 1988), the Honolulu Volcanics on Oahu (Clague and Frey, 1982), and the Kalaupapa Basalt on Molokai (Clague et al., 1982). They should retain significant volatile components, particularly those erupted at the greatest depths. The combination of quenched, relatively-primitive glasses and fresh lava interiors makes such samples ideal to evaluate the spatial distribution of the different mantle source components that melt to produce Hawaiian magmas. In particular, these submarine lavas allow us to include volatile components in our analysis of plume components since the quenched glasses will retain much of their initial complement of water, carbon dioxide, sulfur and rare gases. We have arranged for state-of-the-art volatile analyses of these samples with collaborators Hanyu (rare-gases) and Dixon (water and carbon dioxide). We will determine the degassing history of these lavas as done for Kilauea and North Arch lavas (Dixon et al., 1991, 1997). The rejuvenated stage lavas from the North Arch and those from the main islands are derived mainly from a depleted lithospheric source, but one that has been modified by addition of a component from the Hawaiian plume (Frey et al., 2000; Dixon and Clague, 2000). We hope to define this component and its distribution in space and time. These cones and flows are fairly large and it is unlikely we will be able to sample more than 2 or 3 vents on a single dive, hence our request for so many dives for this important objective.Scheduled Start Date: 2001-03-13 0100 Local Moss Landing time
Expedition Principal Investigator:аKen JohnsonDetailed analysis of the volatile components trapped in these glass sand grains indicate that they erupted at depths of about 2000-2150 m, presumably along the axis of the Puna Ridge (Clague et al., 1995). These glasses are mixed with another type of unusual glass-one that is bubble-rich and slightly enriched in alkalis and depleted in silica (a transitional basalt) compared to most basalt from Kilauea (Clague et al., 1995). Several unusual steep-sided conical vents were mapped by the MBARI Simrad survey in 1998 at about the depth estimated for eruption of these two unusual compositions. These vents contrast with the more typical flat-topped low-aspect-ratio cones (Clague et al., 2000) and linear spatter ramparts seen along all the surveyed submarine rift zones in Hawaii. We suspect that the lavas with the unusual chemistries had either more voluminous and/or more explosive eruptions than the typical Kilauea basalt and therefore constructed these unusual cones. Another fluid lava flow, of alkalic basalt, was mapped in the Hawaiian Deep by the GLORIA surveys in the late 1980s and sampled by dredge in 1988 9Clague et al., in preparation) and again by the Shinkai 6500 submersible in 1999. However, the vents for this flow, which are located at about 3900 m on the south flank of the Puna Ridge based on their volatile contents, have not been found. Collection of near-vent lava is important to determine the volatile content of this flow and to determine the morphology of this high-volume, fluid flow and its vent.Expedition Principal Investigator:аBruce RobisonHilo Ridge was long thought to be the submarine rift zone of Mauna Kea Volcano (e.g., Yang et al., 1994, 1998), but is now proposed to be the submarine southeast rift zone of Kohala Volcano (Holcomb et al., 2000). Samples collected from the rift zone have variable chemisty-some of the dredged samples are geochemically similar to lavas from Kohala, Mauna Kea, and even Kilauea, but none are geochemically similar to the Mauna Kea lavas from near the bottom of the 1.1-km Hawaii Scientific Drilling Project pilot hole drilled near Hilo (Stolper et al., 1996).Younger flank eruptions from Mauna Kea Volcano almost certainly occur in the area, as vents from Mauna Kea are scattered over a large region on land. However, the rift zone is characterized by numerous flat-topped low-aspect ratio cones (Clague et al., 2000) and two submarine (lacking summit craters) steep-sided cones that are probably constructed of alkalic basalt after the tholeiitic shield volcano had been constructed. We want to sample and date (using Ar-Ar techniques) several of the flat-topped cones along the rift to determine if they are similar in age and chemically similar to shield lavas from Kohala or Mauna Kea volcanoes. In addition, we want to confirm that the steep cones are composed of alkalic basalts, determine their eruptive style and depth, and determine when they erupted, providing a maximum age for the end of shield building. These parameters are important in defining the history of the island of Hawaii, the likely character of lava (Mauna Kea or Kohala) to be encountered in the NSF-funded continuation of the already 3-km-deep Hawaii Scientific Drilling Project main hole, and in interpreting the origin of submarine volcanic landforms. These dives form a continuation of a study begun in fall 1998 when Clague used three MBARI-supported Pisces V dives to map 4 flat-topped cones on the flank of Kohala Volcano and determine their compositions. Analyses of these samples establish the compositions of Kohala shield lavas (those exposed on land are too altered) and form the basis for this comparative study. These dives also build on the MBARI Simrad mapping of Hilo Ridge and Kohala Volcanoes done in 1998.Expedition Principal Investigator:David ClagueExpedition Chief Scientist: David Clague
Rock drawerаObjective is to compare surface water iron and aluminum concentrations during a "dust" season to those of a "non-dust" season (the transit to Hawaii). Underway mapping of surface water Iron and Aluminum with tow-fish pneumatic pumping system. Rosette/CTD casts at 8 stations of approximately 2 hrs each to collect metal, nutrient and chlorophyll samples to augment surface mapping findings.David Clague, Charlie Paull, Bill Ussler, Jerry Winterer (SIO), Jennifer Reynolds (U. Alaska), Juli Morgan (Rice U.), Alice Davis, Jenny Paduan, Josh Plant, Randy Keaton, Kyra Schlining67-55 36.6200 122.4150 0 no stop D1,Expedition Principal Investigator:аDavid Clague Expedition Chief Scientist: Bruce RobisonI propose to use the ROV-mounted vibracorer developed at MBARI to collect a series of overlapping cores in order to sample the entire section. This request requires a vibracorer that operates from Tiburon (planned for completion in 2000 by Tiburon pilot group) and 6-8 short, 1050-m dives with Tiburon, with each dive recovering part of the section. The first dive would explore the fault scarp to find the best site for the subsequent coring and would leave a Homer beacon to mark the site; this dive could be coupled to deployment of one of the seismic instruments proposed in the Caress "Microseismicity of Loihi Seamount" proposal. Each subsequent dive can be as short as about 2.5-4 hours, with the sole objective to collect one vibracore from the section. Collection of a complete section of these ashes is something MBARI is uniquely positioned to accomplish because of the vibracorer capability development in 2000 led by Charlie Paull. This Loihi program requires one short (probably 6-hr dive) and 2-3 12-hour Tiburon operational days each with multiple deployments. All but the uppermost core would have to be obtained from a steeply-sloping (30-40-) bottom since the only place the section is exposed is along normal faults. The materials to be cored are sand to gravel with some thin (5 cm) interbeds of siltstone and are ideal for sampling with a vibracorer. The summit region of Loihi has only very sparse animals, so biologic collecting and observation will not be a significant objective on the dive to locate the coring site.Rock drill, with core linersа
top of pageI propose to use the ROV-mounted vibracorer developed at MBARI to collect a series of overlapping cores in order to sample the entire section. This request requires a vibracorer that operates from Tiburon (planned for completion in 2000 by Tiburon pilot group) and 6-8 short, 1050-m dives with Tiburon, with each dive recovering part of the section. The first dive would explore the fault scarp to find the best site for the subsequent coring and would leave a Homer beacon to mark the site; this dive could be coupled to deployment of one of the seismic instruments proposed in the Caress "Microseismicity of Loihi Seamount" proposal. Each subsequent dive can be as short as about 2.5-4 hours, with the sole objective to collect one vibracore from the section. Collection of a complete section of these ashes is something MBARI is uniquely positioned to accomplish because of the vibracorer capability development in 2000 led by Charlie Paull. This Loihi program requires one short (probably 6-hr dive) and 2-3 12-hour Tiburon operational days each with multiple deployments. All but the uppermost core would have to be obtained from a steeply-sloping (30-40-) bottom since the only place the section is exposed is along normal faults. The materials to be cored are sand to gravel with some thin (5 cm) interbeds of siltstone and are ideal for sampling with a vibracorer. The summit region of Loihi has only very sparse animals, so biologic collecting and observation will not be a significant objective on the dive to locate the coring site.Rock drawerа8. Volcanic Vent northeast of Oahupush cores with catchers Planned Track Description:Planned Track Description:This proposal requests 28 Tiburon dive days, admittedly a large number of dive days. Most of these dives will include benthic biology observations and some biological sampling with Jim Barry and George Matsumoto as successfully done on Pioneer, Guide, Gumdrop, Taney, and Davidson Seamounts in 2000. Hawaii is the primary study area for Clague, as it has been for nearly 30 years. The Western Flyer will return to Hawaii no sooner than 2004, so this expedition will provide the data for several years of lab analysis and writing. All but two of the dives proposed are within areas surveyed with the Simrad EM300 system in 1998, so excellent basemaps are in hand.
Hyab crane for tow fish prior to station D3. - JohnsonHeat flow probeаWe request four 12-hr Tiburon dives to observe and collect lava and coral samples from the cones and terraces outlined above. The 400-m terrace is partly overrun by subsequent lavas from Mauna Kea Volcano, whereas the 1150-m terrace has some small cones from an unknown volcano built on top. One dive will collect both the corals and the lavas draping the 400 and the 380-m terraces and another will attempt to sample the 1150-m terrace, where prior dredging (two attempts) failed to recover coralline material. Two dives will explore several of the flat-topped and pointed cones along the deeper (>2000-m) part of the rift. The impact glass sampler will be used here since the lavas have only thin (1 mm) Mn-oxide crusts (as seen in the few dredged samples from the rift) and the box corer should also be useful.2. PapaТu Seamount6 Detritus samplers (2 as spares) Ц Robisonа Teen Webcams Lesbian Sex Pics The submarine east rift zone on Haleakala extends about 135 km from the present shoreline. The shallower half of the rift is characterized by a smooth surface and numerous shoreline terraces, indicating that the region has subsided at least 2200 m and tipped towards the younger Hawaii Island to the south (Moore et al., 1990). Dredging the largest of these submerged terraces recovered corals that proved too old to reliably date using U-series analyses, suggesting that this prominent terrace is older (>500 thousand years) than the oldest terrace found around Hawaii. This once-subaerial surface is disrupted by a cluster of about 20 steep-sided cones (all shallower than about 1 km depth)-only one of which has been sampled. These cones are structurally distinct from subaerial cinder cones (they have no summit craters) and hence are thought to have formed below sea level. Below the deepest shoreline feature, the submarine rift zone resembles the rift zones of Kilauea, Mahukona, and Hilo Ridge with numerous flat-topped volcanic cones (Clague et al., 2000) and linear pillow ridges. In addition, two perched lava ponds were discovered in the Simrad dataset (Clague et al., 2000). These ponds, each several km across, formed above submarine eruptive fissures, built lava levees, and then drained (either back down the eruptive vent or out the side of the pond). Such features indicate that submarine eruptions can be voluminous enough to maintain lava ponds on the seafloor. Exploration of one of these features should confirm our morphologic analysis and provide information about the chemistry, eruptive temperature, and rheology of the lava that built such features.top of pageHilo Ridge was long thought to be the submarine rift zone of Mauna Kea Volcano (e.g., Yang et al., 1994, 1998), but is now proposed to be the submarine southeast rift zone of Kohala Volcano (Holcomb et al., 2000). Samples collected from the rift zone have variable chemisty-some of the dredged samples are geochemically similar to lavas from Kohala, Mauna Kea, and even Kilauea, but none are geochemically similar to the Mauna Kea lavas from near the bottom of the 1.1-km Hawaii Scientific Drilling Project pilot hole drilled near Hilo (Stolper et al., 1996).Younger flank eruptions from Mauna Kea Volcano almost certainly occur in the area, as vents from Mauna Kea are scattered over a large region on land. However, the rift zone is characterized by numerous flat-topped low-aspect ratio cones (Clague et al., 2000) and two submarine (lacking summit craters) steep-sided cones that are probably constructed of alkalic basalt after the tholeiitic shield volcano had been constructed. We want to sample and date (using Ar-Ar techniques) several of the flat-topped cones along the rift to determine if they are similar in age and chemically similar to shield lavas from Kohala or Mauna Kea volcanoes. In addition, we want to confirm that the steep cones are composed of alkalic basalts, determine their eruptive style and depth, and determine when they erupted, providing a maximum age for the end of shield building. These parameters are important in defining the history of the island of Hawaii, the likely character of lava (Mauna Kea or Kohala) to be encountered in the NSF-funded continuation of the already 3-km-deep Hawaii Scientific Drilling Project main hole, and in interpreting the origin of submarine volcanic landforms. These dives form a continuation of a study begun in fall 1998 when Clague used three MBARI-supported Pisces V dives to map 4 flat-topped cones on the flank of Kohala Volcano and determine their compositions. Analyses of these samples establish the compositions of Kohala shield lavas (those exposed on land are too altered) and form the basis for this comparative study. These dives also build on the MBARI Simrad mapping of Hilo Ridge and Kohala Volcanoes done in 1998.
The northeast flank of Oahu shares many characteristics with the north slope of Molokai. The outer part of an terrace is punctuated by a large volcanic cone, most probably related to the rejuvenated stage Honolulu Volcanics on Oahu (Clague and Frey, 1982). This area was mapped with the Simrad EM300 system by the U.S. Geological Survey in 1998, just before the MBARI surveys were collected. The objectives in sampling this cone are similar to those outlined in the section on "Submarine cones and flows" and it is singled out here simply because it is located in a different region.top of pageParticipants:Scoop bags, 12EK-500 water column profiling system Ц Robison (continuous use during transit)Submarine skill saw (if available)Equipment Description (include weight if available):Equipment Description (include weight if available):

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