Geology topics

David A. Clague

Publications and source records attributed to David A. Clague.

27 records · Page 2Linked to original sources

USGS1998

Trace element abundances of high-MgO glasses from Kilauea, Mauna Loa and Haleakala volcanoes, Hawaii

We performed an ion-microprobe study of eleven high-MgO (6.7-14.8 wt%) tholeiite glasses from the Hawaiian volcanoes Kilauea, Mauna Loa and Haleakala. We determined the rare earth (RE), high field strength, and other selected trace element abundances of these glasses, and used the data to establish their relationship to typical Hawaiian shield tholeiite and to infer characteristics of their source. The glasses have trace element abundance characteristics generally similar to those of typical shield tholeiites, e.g. L(light)REE/H(heavy)REE(C1) > 1. The Kilauea and Mauna Loa glasses, however, display trace and major element characteristics that cross geochemical discriminants observed between Kilauea and Mauna Loa shield lavas. The glasses contain a blend of these discriminating chemical characteristics, and are not exactly like the typical shield lavas from either volcano. The production of these hybrid magmas likely requires a complexly zoned source, rather than two unique sources. When corrected for olivine fractionation, the glass data show correlations between CaO concentration and incompatible trace element abundances, indicating that CaO may behave incompatibly during melting of the tholeiite source. Furthermore, the tholeiite source must contain residual garnet and clinopyroxene to account for the variation in trace element abundances of the Kilauea glasses. Inversion modeling indicates that the Kilauea source is flat relative to C1 chondrites, and has a higher bulk distribution coefficient for the HREE than the LREE.

Hawaii↗

USGS1992

Erratum: Geochronology and petrogenesis of MORB from the Juan de Fuca and Gorda ridges by 238U-230Th disequilibrium

A highly precise mass spectrometric method of analysis was used to determine 238 U 234 U 230 Th 232 Th in axial and off-axis basalt glasses from Juan de Fuca (JDF) and Gorda ridges. Initial 230 Th activity excesses in the axial samples range from 3 to 38%, but generally lie within a narrow range of 12 to 15%. Secondary alteration effects were evaluated using δ 234 U and appear to be negligible; hence the 230 Th excesses are magmatic in origin. Direct dating of MORB was accomplished by measuring the decrease in excess 230 Th in off-axis samples. 238 U 230 Th ages progressively increase with distance from axis. Uncertainties in age range from 10 to 25 ka for U Th ages of 50 to 200 ka. The full spreading rate based on U Th ages for Endeavour segment of JDF is 5.9 ± 1.2 cm/yr, with asymmetry in spreading between the Pacific ( 4.0 ± 0.6 cm/yr) and JDF ( 1.9 ± 0.6 cm/yr) plates. For northern Gorda ridge, the half spreading rate for the JDF plate is found to be 3.0 ± 0.4 cm/yr. These rates are in agreement with paleomagnetic spreading rates and topographic constraints. This suggests that assumptions used to determine ages, including constancy of initial 230 Th/ 232 Th ratio over time, are generally valid for the areas studied. Samples located near the axis of spreading are typically younger than predicted by these spreading rates, which most likely reflects recent volcanism within a 1–3 km wide zone of crustal accretion. Initial 230 /Th/ 232 Th ratios and 230 Th activity excesses were also used to examine the recent Th/U evolution and extent of melting of mantle sources beneath these ridges. A negative anomaly in 230 Th/ 232 Th for Axial seamount lavas provides the first geochemical evidence of a mantle plume source for Axial seamount and the Cobb-Eickelberg seamount chain and indicates recent depletion of other JDF segment sources. Large 230 Th activity excesses for lavas from northern Gorda ridge and Endeavour segment indicate formation from a lower degree of partial melting than other segments. An inverse correlation between 230 Th excess and 230 Th/ 232 Th for each ridge indicates that these lower degree melts formed from slightly less depleted sources than higher degree melts. Uniformity in 230 Th excess for other segments suggests similarity in processes of melt formation and mixing beneath most of the JDF-Gorda ridge area. The average initial 230 Th/ 232 Th activity ratio of 1.31 for the JDF-Gorda ridge area is in agreement with the predicted value of 1.32 from the Th Sr isotope mantle array.

Earth and Planetary Science Letters↗

USGS1992

Volcano growth and evolution of the island of Hawaii

The seven volcanoes comprising the island of Hawaii and its submarine base are, in order of growth, Mahukona, Kohala, Mauna Kea, Hualalai, Mauna Loa, Kilauea, and Loihi. The first four have completed their shield-building stage, and the timing of this event can be determined from the depth of the slope break associated with the end of shield building, calibrated using the ages and depths of a series of dated submerged coral reefs off northwest Hawaii. On each volcano, the transition from eruption of tholeiitic to alkalic lava occurs near the end of shield building. The rate of southeastern progression of the end of shield building in the interval from Haleakala to Hualalai is about 13 cm/yr. Based on this rate and an average spacing of volcanoes on each loci line of 40-60km, the volcanoes required about 600 thousand years to grow from the ocean floor to the time of the end of shield building. They arrive at the ocean surface about midway through this period.

Hawaii↗

USGS1991

Origin of xenoliths in the trachyte at Puu Waawaa, Hualalai Volcano, Hawaii

Rare dunite and 2-pyroxene gabbro xenoliths occur in banded trachyte at Puu Waawaa on Hualalai Volcano, Hawaii. Mineral compositions suggest that these xenoliths formed as cumulates of tholeiitic basalt at shallow depth in a subcaldera magma reservoir. Subsequently, the minerals in the xenoliths underwent subsolidus reequilibration that particularly affected chromite compositions by decreasing their Mg numbers. In addition, olivine lost CaO and plagioclase lost MgO and Fe2O3 during subsolidus reequilibration. The xenoliths also reacted with the host trachyte to form secondary mica, amphibole, and orthopyroxene, and to further modify the compositions of some olivine, clinopyroxene, and spinel grains. The reaction products indicate that the host trachyte melt was hydrous. Clinopyroxene in one dunite sample and olivine in most dunite samples have undergone partial melting, apparently in response to addition of water to the xenolith. These xenoliths do not contain CO2 fluid inclusions, so common in xenoliths from other localities on Hualalai, which suggests that CO2 was introduced from alkalic basalt magma between the time CO2-inclusion-free xenoliths erupted at 106??6 ka and the time CO2-inclusion-rich xenoliths erupted within the last 15 ka.

Hawaii↗

USGS1989

South Arch volcanic field—Newly identified young lava flows on the sea floor south of the Hawaiian Ridge

Several young lava fields were imaged by GLORIA sidescan sonar along the Hawaiian Arch south of Hawaii. The largest, 35 by 50 km across, includes a central area characterized by high sonar backscatter and composed of several flow lobes radiating from a vent area. Reflection profiling and sea-floor photography indicate that the central lobes are flat sheet flows bounded by pillowed margins; thin surface sediment and thin palagonite rinds on lava surfaces suggest ages of 1-10 ka. Vents are localized along the arch crest near bases of Cretaceous seamounts. Two dredged flows are basanite and alkalic basalt, broadly similar to rejuvenated-stage and some pre-shield alkalic lavas on the Hawaiian Ridge. Arch volcanism represents peripheral leakage of melt from the Hawaiian hot spot over much larger areas than previously recognized. -Authors

Hawaiian Ridge↗

USGS1989

Shipboard report for Hawaii GLORIA ground-truth cruise F11-88-HW, 25 Oct.-7 Nov., 1988

GLORIA side-scan imagery of the region north of Oahu was collected during two cruises in the spring of 1988. These cruises, F4-88-HW and F6-88-HW, discovered an extensive lava flow field on the Hawaiian Arch and extensive landslide deposits that moved down through the Hawaiian Moat and up onto the Hawaiian Arch. These landslide deposits were apparently derived from two separate submarine failures on the north side of Molokai and the northeast side of Oahu. The cruise reports for these cruises will be released as USGS Open-File Reports in 1989. This report summarizes the results of a subsequent cruise, F11-88-HW on the R/V Farnella, to sample some of the features discovered during the prior GLORIA surveys. Cruise F11-88-HW began in Honolulu on Oct. 25, 1988 and ended in Honolulu on Nov. 7, 1988. The major objectives of the cruise were to sample the giant lava field north of Oahu (Figure 1), to sample an apparently young flow between Oahu and Kauai (Figure 2) , to do some preliminary sampling of the deposits of the Nuuanu giant landslide northnortheast of Oahu, and to determine the thickness of sediment on flows in this lava field to compare to the acoustic backscatter variations observed in the GLORIA imagery of the flow field. These objectives were modified during the cruise due to rough seas which limited the deployment of the camera sled and to problems with the coring equipment which limited us to collecting 10 ft gravity cores. In particular, we did not complete any work aimed directly at the Nuuanu landslide deposits. The comparison of sediment thickness on the flows to observed acoustic backscatter on the GLORIA images was not completed because flows with intermediate backscatter were found to have thicker sediment than we could sample. The other objectives were achieved and lava samples of the flows and vents of the flow field were recovered from 23 locations. Gravity cores on top of the flows also determined the sediment thickness at 12 locations. The flow between Oahu and Kauai was sampled and photographed and found to be young, but clearly not historic in age.

Hawai'i↗

USGS1989

Preliminary geologic map of the Puu Anahulu quadrangle, Hawaii

Vent deposits and lava flows from Hualalai Volcano and lava flows from Mauna Loa and Mauna Kea Volcanoes cover the Puu Anahulu 7 1/2-minute quadrangle. Hualalai's diffuse north-trending rift zone, marked by the large trachyte cone of Puu Waawaa and several basaltic spatter cones, is located mainly in the southwestern part of the quadrangle. Several Hualalai flows originated in the Hualalai quadrangle, crossed the Puu Anahulu quadrangle, and terminated in the Kiholo quadrangle. Hualalai flows cover most of the western half of the quadrangle and are interlayered with Mauna Loa lavas along a 2-kilometer-wide strip from southeast to northwest across the middle of the Puu Anahulu quadrangle. Mauna Loa flows cover most of the eastern half. Mauna Kea flows are restricted to the northeastern corner, where they underlie Hualalai and Mauna Loa lavas. A few extensive and relatively young flows from Hualalai and Mauna Loa cover most of the quadrangle; thus, the older units are generally small in area. The oldest units in the quadrangle are the trachyte cone of Puu Waawaa and its flow, which includes Puu Anahulu, covers about 7 percent of the quadrangle. Basaltic lavas of Hualalai range in age from latest Pleistocene to less than 2,000 years. Pleistocene lavas cover about 5 percent of this quadrangle, lavas that are 5,000 - 10,000 years old cover about 5 percent, lavas that are 3,000 - 5,000 years old cover about 3 percent, and three extensive flows that are 1,500 - 3,000 years old cover about 25 percent. The oldest Mauna Loa flows, that are probably 5,000 - 10,000 years old, cover about 2 percent of this quadrangle, flows that are 3,000 - 5,000 years old cover about 18 percent, six extensive flows that are 1,500 - 3,000 years old cover about 23 percent, and the 1859 flow, that is the youngest volcanic unit, and covers about 10 percent of its area. Two hawaiite flows from Mauna Kea, that are late Pleistocene in age, cover about 2 percent of the quadrangle.

Hawaii↗

USGS1981

Linear island and seamount chains, aseismic ridges and intraplate volcanism: Results from DSDP

The Deep Sea Drilling Project drilled a substantial number of sites that bear on the origin of linear island and seamount chains, aseismic ridges and other more regional expressions of intraplate volcanism. Drilling in the Emperor Seamounts during Leg 55 was particularly successful. Results from this leg include: 1) the volcanoes of the Hawaiian-Emperor chain continue to increase in age away from Kilauea as predicted. 2) Suiko Seamount formed at a paleolatitide of 26.9±3.5°N, 7° north of present-day Hawaii, but far south of its present latitude of 44.8°N. 3) the volcanic rock types recovered include hawaiite, mugearite, alkalic basalt and tholeiitic basalt in the sequence and relative volume expected for Hawaiian volcanoes. 4) the tholeiitic and alkalic basalts recovered are geochemically similar to those in the Hawaiian Islands, only the ratio of 87 Sr/ 86 Sr appears to change through time. All the lavas appear to be derived from a source that has small-scale heterogeneities, but is homogeneous on a large scale. 4) The Emperor Seamounts were once volcanic islands that underwent subaerial and shallow marine erosion, and deposition of shallow-water biogenic carbonate sediments that capped all or most of each volcano. Drilling in other regions has yielded less conclusive results. For example, it is uncertain if the Line Islands are an age progressive chain (hot-spot trace) or result from some other type of intraplate volcanism. The mid-Pacific Mountains also show evidence of originating from a regional episode of volcanism in the mid-Cretaceous. Drilling in the Nauru Basin encountered a voluminous mid-Cretaceous volcanic flow-sill complex that overlies Jurassic magnetic anomalies, yet is composed of depleted tholeiite. In the Indian Ocean, drilling on the Ninety-East Ridge established that it 1) is volcanic in origin; 2) is older to the north; 3) formed in shallow water, and 4) formed further south and has moved northward. It appears that the Ninety-East Ridge, like the Hawaiian-Emperor chain, is a hot spot trace. In the Atlantic Ocean, drilling on the Iceland-Faeroe Ridge and the Rio Grande Rise-Walvis Ridge suggests that all these aseismic ridges are hot spot traces generated by the Iceland and Tristan de Cunha hot-spots.

SEPM Special Publication↗

USGS1973

Age of Kōko Seamount, Emperor Seamount chain

K— Ar ages obtained by the conventional isotope-dilution and the 40 Ar/ 39 Ar techniques on two sanidine trachytes, four basalts, and a phonolite dredged from the top of Kōko Seamount, 300 km north of the Hawaiian-Emperor bend, show that the seamount is 46.4 ± 1.1 my old. These data indicate that the volcanoes in the Hawaiian-Emperor chain continue to increase in age to the west and north beyond Midway Atoll, as predicted by the melting-spot hypothesis for the origin of the chain, and that the rate of volcanic migration along the chain was nonlinear between the time of formation of the island of Hawaii and Kōko Seamount.

Earth and Planetary Science Letters↗