Core lithology, State of Hawaii Scientific Observation Hole 4 Kilauea Valcano, Hawaii

Trusdell, Frank A.; Novak, Elizabeth A.; Evans, Sian

doi:10.3133/ofr92586

Cited by 13 publications

(9 citation statements)

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“…The SOH‐4 drill core is stored at the University of Hawaii's Research Facility in Snug Harbor, Honolulu. We examined the upper 925 m of the core (boxes 1–299) with the aid of a logbook that provided preliminary flow type and thickness [ Trusdell et al , 1992]. This half of the 1985 m core contains most of the subaerial flows.…”

Section: Methodsmentioning

confidence: 99%

Hawaiian lava flows in the third dimension: Identification and interpretation of pahoehoe and ′a′a distribution in the KP‐1 and SOH‐4 cores

Katz

Cashman

2003

Geochem Geophys Geosyst

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[1] Hawaiian lava flows are classified as pahoehoe or`a`a by their surface morphology. As surface morphology reflects flow emplacement conditions, the surface distribution of morphologic flow types has been used to study the evolution and eruptive history of basaltic volcanoes. We extend this analysis to the third dimension by determining the distribution of flow types in two deep drill cores, the Scientific Observation Hole-4 (SOH-4) core, drilled near Kilauea's East Rift Zone (ERZ), and the pilot hole (Kahi Puka-1 (KP-1)) for the Hawaiian Scientific Drilling Project (HSDP), drilled through distal flows from Mauna Loa and Mauna Kea. Flows are classified using both internal structures and groundmass textures, with the latter useful when identification based on mesoscopic flow features (e.g., surface morphology and vesicle content and distribution) is ambiguous. We then examine the temporal distribution of pahoehoe and`a`a flows in proximal (SOH-4) and distal (KP-1) settings. Sequence analysis shows that the two flow types are not randomly distributed in either core but instead are strongly clustered. The proximal SOH-4 core is dominated by thin pahoehoe flows ($60% by volume), consistent with the common occurrence of surface-fed pahoehoe flows in near-vent settings. The distal KP-1 core has a high proportion of`a`a ($58% by volume), although the proportion of pahoehoe and`a`a varies dramatically throughout the Mauna Kea sequence. Thick inflated pahoehoe flows dominate when the drill site was near sea level, consistent with the numerous inflated pahoehoe fields on the current coastal plains of Kilauea and Mauna Loa.`A`a flows are abundant when the site was far above sea level. As slope increases from the coastal plains to Mauna Kea's flank, this correlation may reflect the combined effect of long transport distances and increased slopes on flow emplacement. These results demonstrate that flow type and thickness variations in cores provide valuable information about both vent location and local site environment. Observed variations in flow type within the KP-1 core raise interesting questions about feedback between volcano evolution and flow morphology and suggest that flow type is an important variable in models of volcano growth and related models for lava flow hazard assessment.

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Section: Methodsmentioning

confidence: 99%

Hawaiian lava flows in the third dimension: Identification and interpretation of pahoehoe and ′a′a distribution in the KP‐1 and SOH‐4 cores

Katz

Cashman

2003

Geochem Geophys Geosyst

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“…Continuously cored exploratory holes from the Kilauea Volcano generally lack saprolite or soil horizons (Novak et al, 1991;Trusdell et al, 1992Trusdell et al, , 1999. These boreholes penetrated from 580 to 1800 m of subaerial volcanic material, and only one of them describe a 'possible soil' (Trusdell et al, 1999) at a depth of 42 m. Thermal alteration is common, including the deposition of amorphous silica, chlorite, calcite, gypsum/anhydrite, Fe-sulfides, quartz, albite, and zeolites as well as blue or black staining indicative of smectite clay formation. However, there is little or no indication of the formation of LWPs during the construction of the Kilauea shield.…”

Section: Geologic and Hydrologic Settingmentioning

confidence: 99%

Application of HVSR to estimating thickness of laterite weathering profiles in basalt

Nelson

McBride

2019

Earth Surf Processes Landf

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Lateritic weathering profiles (LWPs) are widespread in the tropics and comprise an important component of the Critical Zone (CZ). The Hawaiian Islands make an excellent natural laboratory for examining the tropical CZ, where the bedrock composition (basalt) is nearly uniform and rainfall varies greatly. This natural laboratory is employed to assess the utility of the HVSR (horizontal/vertical spectral ratio) method to characterize the shear‐wave velocity (Vs) structure of LWPs, particularly the depth to the contact between saprolite and basalt bedrock. LWP thicknesses determined from HVSR provide good agreement with multi‐channel analysis of surface waves (MASW) profiles, well logs and outcrop. LWP thicknesses may be estimated from the fundamental mode equation or through forward models. Prior knowledge about the subsurface from well, outcrop, and MASW profiles may greatly aid modeling in some cases. For the 3.2 to 1.8 Ma Koolau Volcano on Oahu, the downward rate of advance of the weathering front varies from 0.004 to 0.041 m/ka. For the 0.44 to 0.10 Ma Kohala Volcano (Big Island of Hawaii) rates vary from 0.013 to 0.047 m/ka. Simple H/V spectra develop in areas where the combined effects of time and elevated rainfall produce thick LWPs with a flat base and a general absence of core stones with an ideal layered geometry. Abundant buried core stones violate the assumption of simple layered geometries and scatter acoustic energy, leading to uninterpretable results. This is common where low rainfall and a young basaltic substrate leave abundant core stones as well as an undulating contact between saprolite and bedrock. Velocity inversions (high Vs intervals within low Vs saprolite) may also be present and originate from relatively intact bedrock horizons or mineralogical changes within saprolite. At Kohala, a gibbsite‐rich horizon produces such a velocity inversion due to enhanced weathering and subsequent collapse of saprolite in a discrete horizon. © 2019 John Wiley & Sons, Ltd.

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“…We speculate that Kauai laterite thicknesses well below the regression line ( Figure 4B) may have experienced significant lateral vadose flow that protected subjacent rock from extensive contact with water. This is expected in Hawaiian shield volcanoes where reported clinker horizons in deep core, for example, have a mean thickness of 3.1±1.6m and range from 0.9 to 7m (calculated from Trusdell et al, 1992). Combined with variations in other volcanic textures, the variations in clinker horizons alone suggest large heterogeneities in horizontal permeability.…”

Section: Laterite Thickness As a Function Of Age And Rainfallmentioning

confidence: 70%

“…Sowards et al (2018) suggested that one such zone of lateral flow may have experienced very large water-rock ratios, extreme weathering, and subsequent collapse, although the bulk of the rock experiences presumed isovolumetric weathering. Using data from a published lithologic log for a deep borehole from Kilauea, Hawaii (Trusdell et al, 1992),~5% of basalt shield stratigraphy was categorized as 'breccia' or 'clinker'.…”

Section: Laterite Thickness As a Function Of Age And Rainfallmentioning

confidence: 99%

The lateral and vertical growth of laterite weathering profiles, Hawaiian Islands, USA

Nelson

Barton

Burnett

et al. 2020

Earth Surf Processes Landf

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The Hawaiian Islands permit investigation of tropical chemical weathering rates and processes on a single rock type, basalt. Chronosequences are investigated as a function of rainfall due to the varying age of each island, including Kauai (~4 Ma), Oahu (~2 Ma), and Hawaii's Kohala Peninsula (~0.3 to 0.17 Ma). Understanding tropical critical zone (CZ) development is vital given the large populations in developing countries that rely on it. HVSR (horizontal‐to‐vertical spectral ratio) seismic soundings on Kauai indicate that ~60% of the variability in laterite thickness is due to gradients in precipitation, with errors in erosion corrections and variability in the original permeability structure of the volcanic sequence playing important roles. Basalts have higher horizontal than vertical hydraulic conductivity (Kh > Kv), and local variability in KhKv likely drives much of the remaining differences in laterite thickness. HVSR is well suited for estimating laterite thickness as it has been shown to reliably detect the base of the weathering profile, is rapid (20 min/sounding), highly portable, and occupies a very small footprint. Comparison of Kauai and Oahu weathering profiles suggests that the Oahu laterites are fully or nearly fully formed, despite being half the age of Kauai. By contrast, the young laterites on Kohala (~170 to ~300 ka) exhibit greatly contrasting thicknesses, where coastal laterites are thick and interior laterites are thin, suggesting that early weathering on shield volcanoes produces wedge‐shaped laterites near the coast. With time, the thick (coastal) end of the wedge propagates upslope such that a fully developed, constant‐thickness laterite carapace can form in ~2 Ma or less. The development of thickened coastal laterites on young substrates depends on greater water–rock ratios as vertically infiltrating water upslope is diverted laterally. This view of laterite development is very different compared to endmember models of continental weathering and CZ development. © 2020 John Wiley & Sons, Ltd.

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Core lithology, State of Hawaii Scientific Observation Hole 4 Kilauea Valcano, Hawaii

Cited by 13 publications

References 0 publications

Hawaiian lava flows in the third dimension: Identification and interpretation of pahoehoe and ′a′a distribution in the KP‐1 and SOH‐4 cores

Hawaiian lava flows in the third dimension: Identification and interpretation of pahoehoe and ′a′a distribution in the KP‐1 and SOH‐4 cores

Application of HVSR to estimating thickness of laterite weathering profiles in basalt

The lateral and vertical growth of laterite weathering profiles, Hawaiian Islands, USA

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