ライフサイエンスコーパス: basalt

1 olving the oxidation and hydration of glassy basalt.

2 ues previously measured in a mid-ocean-ridge basalt.

3 ng siderite formed in experiments with flood basalt.

4 d recycling of the resulting mid-ocean-ridge basalt.

5 rine in the source of normal mid-ocean-ridge basalt.

6 the pyroxenitic remnants of recycled oceanic basalt.

7 o the +0.1 per thousand shift of terrestrial basalts.

8 distinguishable from that of mid-ocean ridge basalts.

9 -may strongly affect the generation of flood basalts.

10 seawater-derived fluids in ocean ridge flank basalts.

11 xplain the 186Os-187Os signatures of oceanic basalts.

12 l trends from nephelinites to alkali olivine basalts.

13 s volatile and degasses from erupted oceanic basalts.

14 es and higher water content of plume-derived basalts.

15 and isotopic similarities to mid-ocean-ridge basalts.

16 trations of ocean island and mid-ocean-ridge basalts.

17 ry of both normal and hotspot-affected ridge basalts.

18 come the source material for mid-ocean-ridge basalts.

19 he observed presence of water in ocean-floor basalts.

20 ndeed be the sole source for mid-ocean-ridge basalts.

21 by ocean island basalts and mid-ocean-ridge basalts.

22 end of the (143)Nd/(144)Nd variations of the basalts.

23 ltered and low-temperature aqueously altered basalts.

24 ower than any yet reported from ocean-island basalts.

25 observed in mid-ocean ridge or ocean island basalts.

26 stinct deeper-mantle source for ocean island basalts.

27 alogy and thus the depth of melting of these basalts.

28 elieved to have fed the eruption of the SLIP basalts.

29 subduction-related signatures of gabbros and basalts.

30 al composition to one influenced by alkaline basalts.

31 Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn cond

32 easurements of late-stage apatite from lunar basalt 14053 that document concentrations of H, Cl and S

33 HC-III was abundant in basalt (36%) but absent in chalk; HC-IV was prevalent in

34 but absent in chalk; HC-IV was prevalent in basalt (46.5%) but was low (20%) in chalk.

35 C and PCO2 = 280 bar on a Mg-rich tholeiitic basalt (9.3 wt % MgO and 12.2 wt % CaO) composed of oliv

36 The Pleistocene Alma basalt abuts the Cretaceous Senonian Kerem Ben Zimra cha

37 even individual eruptions during past flood basalt activity was probably severe.

38 light Zn condensates also occur on some mare basalts after their crystallization, confirming a volati

39 tween the extinction horizon and lowest CAMP basalts allows this sedimentary Hg excursion to be strat

40 er cent to 30 per cent melting of the Coucal basalts along high geothermal gradients (of more than 70

41 existence of microbes that are supported by basalt alteration is lacking.

42 Basalt alteration reactions are theoretically capable of

43 oincidence between locations of such altered basalt and a suggested northern ocean basin implies that

44 control region and ATP6 in 28 mole rats from basalt and in 14 from chalk habitats.

45 d simulations of model basalt, hydrous model basalt and near-MORB to assess the effects of iron and w

46 Fe in basalt and paleosol samples was extracted and purified u

47 k between vertical amphitheater headwalls in basalt and rapid erosion during megaflooding due to the

48 carbon cycling and chemical exchange between basalt and sea water.

49 bonaceous cherts from the Early Archean Apex Basalt and Towers Formation of northwestern Western Aust

50 ched crustal rock compositionally similar to basalts and average martian crust measured by recent Rov

51 (66)Zn between bulk silicate Earth and lunar basalts and crustal rocks, the volatile loss likely occu

52 ically and texturally similar to terrestrial basalts and cumulates, except that they have higher conc

53 d the chlorine isotope composition of Apollo basalts and glasses and found that the range of isotopic

54 ally more treefall occurred on high-nutrient basalts and in lowland catena areas.

55 lar to primitive terrestrial mid-ocean ridge basalts and indicate that some parts of the lunar interi

56 t abundant volatile component in terrestrial basalts and is a significant constituent of the gases th

57 e compositions intermediate between those of basalts and komatiites.

58 chlorine and bromine relative to terrestrial basalts and martian meteorites; sulphur, chlorine and fe

59 mantle components as sampled by ocean island basalts and mid-ocean-ridge basalts.

60 n (3)He/(4)He ratios between mid-ocean-ridge basalts and ocean island basalts, as well as high concen

61 tion of the interface between Columbia River basalts and other geological formations indicates that m

62 By comparing the isotopic compositions of basalts and peridotites at two segments of the southwest

63 er 187Os/188Os ratios than most ocean-island basalts and some extend to subchondritic 187Os/188Os rat

64 lavas are more oxidized than mid-ocean-ridge basalts and subduction introduces oxidized components in

65 res in volcanic glass from Cenozoic seafloor basalts and the corresponding titanite replacement micro

66 ry of the valence state of Fe in primary arc basalts and their mantle sources.

67 contrast in MgO content between peridotite, basalt, and sediment makes direct mixing between sedimen

68 Instead, the dominant lithology is basalt, and the dominant geologic processes are impact e

69 ater than those in metamorphosed terrestrial basalts, and can retain it at greater depths within Mars

70 tantial decreases in mantle melt fraction in basalts, and in indicators of deep crustal melting and f

71 the trace-element composition of the Coucal basalts, and propose that these rocks were themselves de

72 the upper mantle sampled by mid-ocean-ridge basalts, and that buoyantly upwelling plumes from the de

73 global environmental change than their flood basalt- and/or dike-dominated counterparts.Although the

74 Flood basalts appear to form during the initiation of hotspot

75 e spectrum of 4He/3He ratios in ocean island basalts appears to preserve the mantle's depletion histo

76 nges in hydration that were greater for mare basalts (approximately 70%) than for highlands (approxim

77 equestration in established sediment-covered basalt aquifers on the Juan de Fuca plate offer promisin

78 karyotic cell abundances on seafloor-exposed basalts are 3-4 orders of magnitude greater than in over

79 Olivine basalts are observed on crater floors and in layers expo

80 al data confirm that the West Siberian Basin basalts are part of the Siberian Traps and at least doub

81 Basalts are recognized as one of the major habitats on E

82 High 3He/4He ratios found in ocean island basalts are the main evidence for the existence of an un

83 signatures, ocean-island and mid-ocean-ridge basalts are traditionally inferred to arise from separat

84 ern lowlands can be interpreted as weathered basalt as an alternative to andesite.

85 nerate wetter and more enriched ocean-island basalts) as well as the hotter Archaean mantle (thereby

86 composition resulting from the weathering of basalts, as reflected in the chemical compositions at Ma

87 4He/3He peak found in modern mid-ocean-ridge basalts, as well as estimates of the initial 4He/3He rat

88 een mid-ocean-ridge basalts and ocean island basalts, as well as high concentrations of (3)He and (40

89 trusion, mixing and mobilization of coal and basalt, ascent to the surface, explosive combustion, and

90 mid-ocean-ridge basalts, we demonstrate that basalts associated with mantle plume components containi

91 (CRB) represent the largest volume of flood basalts associated with the Yellowstone hotspot, yet the

92 presence of jarosite combined with residual basalt at Meridiani Planum indicates that the alteration

93 ulations simulate the chemical weathering of basalt at relevant martian conditions.

94 ion of the extinction with the Siberia flood basalts at approximately 250 Ma is well known, and recen

95 thin pyroxenes of the Shergotty meteorite--a basalt body ejected 175 million years ago from Mars--as

96 t constraints on the sources of ocean-island basalts, but two very different models have been put for

97 pths, and the composition of mid-ocean ridge basalts can all be used to determine variations in mantl

98 s that the radiogenic osmium in ocean-island basalts can better be explained by the source of such ba

99 (40)Ar in the mantle source of ocean island basalts, can be explained within the framework of differ

100 Continental flood basalt (CFB) volcanism is hypothesized to have played a

101 tified a homologous recombinant mtDNA in the basalt/chalk studied area.

102 ly, all the fine-grained material is alkalic basalt, chemically identical (except for sulphur, chlori

103 might be reflected in spatial variations of basalt composition observed at the Earth's surface.

104 f clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile ele

105 Using experiments on a lunar basalt composition, we confirm that carbon dissolves as

106 consistent with known lunar anorthosite and basalt compositions.

107 ic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate.

108 Icelandic and northeast Atlantic basalts contain variable proportions of two enriched com

109 lithosphere--'enriched-mantle' or 'EM-type' basalts--contain less water than those associated with a

110 an better be explained by the source of such basalts containing a component of recycled crust.

111 ay Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagio

112 w that the martian crust, while dominated by basalt, contains a diversity of igneous materials whose

113 Fractures and pores in basalt could provide substantial pore volume and surface

114 The Columbia River basalts (CRB) represent the largest volume of flood basa

115 , we report analyses of two 3.56-Gy-old mare basalts demonstrating that they were magnetized in a sta

116 l analysis of explosive eruption of coal and basalt, demonstrating that it is a viable mechanism for

117 traction from the mantle and mid-ocean-ridge basalt differentiation.

118 Host-basalt dissolution releases nutrients and energy sources

119 nd barium) were added to eclogite (subducted basalt) during high pressure/temperature metamorphism vi

120 ncompatible element-enriched mid-ocean ridge basalts (EMORBs) as far as 20 kilometers off axis.

121 s of this reservoir contributed to the flood basalt emplaced on Baffin Island about 60 million years

122 ry and that >1.1 million cubic kilometers of basalt erupted in ~750,000 years.

123 shed data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track.

124 ed by volatilization of metal halides during basalt eruption--a process that could only occur if the

125 acoustic signatures of dike emplacement and basalt eruptions at ridge crests in the northeast Pacifi

126 The impact of these flood basalt eruptions on the global atmosphere and the coeval

127 een magma and coal during the Siberian flood-basalt eruptions released large amounts of CO2 and CH4 i

128 the Triassic-Jurassic boundary during flood basalt eruptions.

129 es during the SCR-Northern Nevada Rift flood basalt event both in space and time.

130 ution and carbonation reactions in fractured basalts exposed to CO2-acidified fluids.

131 These basalts extend the known range of rock compositions comp

132 with diverse magma flux within several flood basalts extending over tens of million years.

133 ssing during the eruption of the Deccan Trap basalts fails to fully account for the inferred pCO(2) i

134 km wide on the transition, although extruded basalts flow more than 100 km from the rift.

135 The Central Atlantic Magmatic Province basalt flows along the eastern seaboard of the United St

136 ls indicate that last-gasp eruptions of thin basalt flows continued until less than 1.0 Gyr ago, but

137 s a viable alternative to models of alkaline basalt formation by melting of recycled oceanic crust wi

138 Basalt formations could enable secure long-term carbon s

139 Injection into basalt formations provides unique and significant advant

140 Injection into deep-sea basalt formations provides unique and significant advant

141 face rocks on Mars are dominantly tholeiitic basalts formed by extensive partial melting and are not

142 Steel coupons and basalt fragments were added to the cement paste in order

143 esults from a laboratory experiment in which basalt from Mount Etna volcano (Italy) was deformed and

144 Here we show that mid-ocean ridge basalts from 2,000 km along the southeast Indian ridge (

145 e of tabulated measured (3)He(4)He ratios of basalts from along the global spreading ridge system.

146 The highest 3He/4He basalts from Hawaii and Iceland plot on the observed mix

147 We report analyses of iron isotopes in basalts from Kilauea Iki lava lake, Hawaii.

148 phides from 20-million-year-old ocean island basalts from Mangaia, Cook Islands (Polynesia), which ha

149 Many basalts from oceanic islands, ridges, and arcs show stro

150 Basalts from the Earth and the Moon do indeed appear to

151 a notable range in lithium isotope ratios in basalts from the East Pacific Rise, which correlate with

152 dstones, shales, carbonates, evaporites, and basalts from the Frio, In Salah, Illinois Basin, Decatur

153 Here we show that basalts from the largest volcanic event in geologic hist

154 ium- and platinum-group element data set for basalts from the Moon establishes that the basalts have

155 atile content for a suite of mid-ocean-ridge basalts from the Siqueiros intra-transform spreading cen

156 r-Nd-Pb isotope ratios and trace elements in basalts from the spreading axis, we show that the sparse

157 re of the enriched mantle I (EM I) source of basalts from, for example, Pitcairn or Walvis Ridge has

158 y cratered crust in the southern hemisphere (basalt) from younger lowland plains in the north (andesi

159 ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperatur

160 all titanite-based textures in metamorphosed basalt glass, but a cautious and critical evaluation of

161 n of bioalteration trace fossils in Cenozoic basalt glasses and their putative equivalents in Paleoar

162 Through a global survey of mid-ocean ridge basalt glasses, we show that mantle oxidation state vari

163 d tent) and seven natural mineral particles (basalt, granite, hematite, magnetite, mica, milky quartz

164 ngold Formation sediments, and the weathered basalt group.

165 isms, which constitute a trophic base of the basalt habitat, with important implications for deep-sea

166 ost other ocean island basalts, the Terceira basalt has a (210)Pb deficit, which we attribute to 8.5

167 -resolution eruption timeline for the Deccan basalts has prevented full assessment of their relations

168 isotopic signature of Indian mid-ocean ridge basalts has remained enigmatic, because the geochemical

169 high (3)He/(4)He ratios observed in oceanic basalts have been considered the main evidence for a 'pr

170 High (3)He/(4)He ratios in some basalts have generally been interpreted as originating i

171 Primary arc and mid-ocean ridge basalts have identical Cu contents, indicating that the

172 r basalts from the Moon establishes that the basalts have uniformly low abundances of highly sideroph

173 degrees N) and around Hawaii reveal that the basalt-hosted biosphere harbours high bacterial communit

174 w-temperature ( approximately 15 degrees C), basalt-hosted diffuse effluents.

175 in, and the Sandy Hook basin offer promising basalt-hosted reservoirs with considerable potential for

176 functional theory-based simulations of model basalt, hydrous model basalt and near-MORB to assess the

177 emical exchange between seawater and oceanic basalt in hydrothermal systems at midocean ridges (MOR).

178 ence showing that partial melting of hydrous basalt in the eclogite facies produces granitoid liquids

179 tinue to indicate the dominance of unaltered basalt in the southern highlands, but reveal that the no

180 es, for example, an exposure of olivine-rich basalt in the walls of Ganges Chasma.

181 rial environments slightly before the oldest basalts in eastern North America but simultaneous with t

182 F, S and Cl) contents of the most primitive basalts in the Moon-the lunar volcanic glasses.

183 ng 231Pa-235U data obtained from continental basalts in the southwestern United States and Mexico.

184 s measured in Icelandic and Hawaiian oceanic basalts indicate that the demise of the georeactor is ap

185 ts from variations in the movement of molten basalt into and out of the Yellowstone volcanic system.

186 or every 1 km along strike, 360-400 km(3) of basalt is extruded, while 540-600 km(3) is intruded into

187 because the geochemical composition of these basalts is consistent either with pollution from recycle

188 ause the volatile content of mid-ocean-ridge basalts is generally too low to produce the gas fraction

189 ion of the 'plume' component in ocean island basalts is lower than that predicted for a two-layer, st

190 nd whether it has contributed to other flood basalts is not known.

191 upper mantle, as sampled by mid-ocean ridge basalts, is highly depleted in incompatible elements, su

192 eading to the toppling and transportation of basalt lava columns.

193 and other geochemical attributes in oceanic basalts less than 20 years old to infer that melts of th

194 ed and chlorine-contaminated mid-ocean-ridge basalt magmas, and hence constrain degassing and contami

195 n the timing and magnitude of Columbia River basalt magmatism, as well as the surface uplift and exis

196 e similar in inferred mineral composition to basalt mapped from orbit.

197 rface areas sequestered more carbon per unit basalt mass than powder with low surface area.

198 y suggesting that such ultramafic (picritic) basalts may be relatively common.

199 These basalts may be the remnants of a thick (more than 35 kil

200 Mare basalts may contain hydrogen-rich apatite, but lunar mag

201 Thus, the mantle source of these martian basalts may have a redox state close to that of the iron

202 wn, and recent evidence suggests these flood basalts may have mobilized carbon in thick deposits of o

203 na Kea are more oxidized than midocean ridge basalt (MORB) magmas, suggesting that the upper mantle s

204 ogenic isotope variations in mid-ocean ridge basalts (MORB) are commonly attributed to compositional

205 Chemical differences between mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs) provide

206 We also find that mid-ocean-ridge basalts (MORBs) have (238)U/(235)U ratios higher than do

207 basalts (OIBs) compared with mid-ocean-ridge basalts (MORBs) have been used as evidence for the exist

208 relatively uniform values in mid-ocean-ridge basalts (MORBs), are thought to result from a well mixed

209 up to sixfold higher than in mid-ocean ridge basalts (MORBs).

210 resent the mantle residue of mid-ocean-ridge basalts (MORBs).

211 metrical eruptions of normal mid-ocean ridge basalts (NMORBs) and incompatible element-enriched mid-o

212 ample-return sites and is a new type of mare basalt not previously sampled, but consistent with remot

213 bedded chert unit of the Early Archean Apex Basalt of northwestern Western Australia.

214 at probably formed via aqueous alteration of basalt of the ancient cratered terrain.

215 n widely attributed to the eruption of flood basalts of the Central Atlantic Magmatic Province.

216 ra Terrane, Western Australia, low-magnesium basalts of the Coucal Formation at the base of the Pilba

217 ments on plagioclase crystals separated from basalts of the Rajmahal Traps (113 to 116 million years

218 ungsten isotope data for modern ocean island basalts (OIB) from Hawaii, Samoa, and Iceland reveal var

219 The isotopic diversity of oceanic island basalts (OIB) is usually attributed to the influence, in

220 Although many ocean island basalts (OIBs) are argued to contain a recycled componen

221 enic xenon ((129)Xe/(130)Xe) in ocean island basalts (OIBs) compared with mid-ocean-ridge basalts (MO

222 n much lower eruption rates for ocean island basalts (OIBs) in comparison with those of lavas from la

223 ocean ridge basalts (MORBs) and ocean island basalts (OIBs) provide critical evidence that the Earth'

224 3He/4He ratios in many ocean-island basalts (OIBs) that erupt at hotspot volcanoes, such as

225 significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro.

226 Sediment-covered basalt on the flanks of mid-ocean ridges constitutes mos

227 the degassing of reduced carbon from Fe-rich basalts on planetary bodies would produce methane-bearin

228 We determine that the Martian basalt pebbles have been carried tens of kilometres from

229 nt is important for studies of ore deposits, basalt petrogenesis, and precious metal geology, mineral

230 ces between mid-ocean-ridge and ocean-island basalts place important constraints on the form of mantl

231 ion of thorium- and titanium-rich lunar mare basalts, plausibly results in a core heat flux sufficien

232 n in filled vugs and veins within the plains basalts; positive correlations between magnesium, sulphu

233 e element-depleted source of mid-ocean ridge basalts, possibly as a result of a global differentiatio

234 Packed beds of basalt powder with large specific surface areas sequeste

235 we show that olivine phenocrysts in picritic basalts presumably derived from the proto-Iceland plume

236 an unequivocal link between an onshore flood basalt province, continental break-up and a hot-spot tra

237 ute one of Earth's largest continental flood basalt provinces, whose eruption played a role in the Cr

238 ols caused by eruptions of continental flood basalt provinces.

239 ing, compatible and incompatible elements in basalts record gradually decreasing mantle melt fraction

240 -238U disequilibrium data on mid-ocean ridge basalts recovered 5 to 40 kilometers off the ridge axis

241 s and the upper-mantle source of ocean-ridge basalts reflect isolation of plume sources from the conv

242 elevated (56)Fe/(54)Fe ratio of terrestrial basalts relative to chondrites was proposed to be a fing

243 new global data compilation of ocean island basalts, representing upwelling 'plumes' from the deep m

244 -partitioning during incipient weathering of basalt, rhyolite, granite and schist depends on the acti

245 In situ pH measurements for a basalt rock-CO(2)-brine system were conducted under GCS

246 easurements on the 3.7-billion-year-old mare basalt sample 10020.

247 d trace elements when compared to a standard basalt sample with known concentrations.

248 incorporated by segmenting an actual reacted basalt sample, and these results were compared to equiva

249 Five different basalt samples were immersed in water equilibrated with

250 Although all mantle plume (ocean island) basalts seem to contain more water than mid-ocean-ridge

251 amarium-neodymium isotope data for six lunar basalts show that the bulk Moon has a 142Nd/144Nd ratio

252 he present-day mantle, as sampled by oceanic basalts, shows large chemical and isotopic variability b

253 ave resulted from explosive interaction with basalt sills of the Siberian Traps.

254 ate that the Pacific and Indian upper mantle basalt source domains were each affected by different me

255 major portions of the Indian mid-ocean ridge basalt source region has been a long-standing problem.

256 anism for generating Os isotope diversity in basalt source regions.

257 l content than in the modern mid-ocean-ridge basalt source.

258 ional similarity between all mid-ocean-ridge basalt sources.

259 er stepped altar platforms and use of pecked basalt stones associated with the late 'Oro cult.

260 mal erosion, indicate emplacement in a flood-basalt style, consistent with x-ray spectrometric data i

261 high (3)He/(4)He ratios in some ocean-island basalts suggest the presence of relatively undegassed an

262 th as well as the eruption of McKinney Butte Basalt, suggesting widespread canyon formation following

263 s have identical Zn/Fe(T) to mid-ocean-ridge basalts, suggesting that primary mantle melts in arcs an

264 to indicate that the surface is composed of basalt (Surface Type 1) and andesite (Surface Type 2).

265 es exhibit a range of compositions including basalt, syenite, andesite, and a soil.

266 e that the 3He-rich end-member is present in basalts that are derived from large-volume melts of depl

267 e/(4)He ratios identified in mid-ocean-ridge basalts that form by melting the upper mantle (about 8Ra

268 e and partial melting to become ocean island basalt, the HIMU source formed as Archean-early Proteroz

269 isotope (186Os-187Os) signatures in oceanic basalts, the possibility of material flux from the metal

270 Like most other ocean island basalts, the Terceira basalt has a (210)Pb deficit, whic

271 Converting basalt to more felsic compositions requires a second ste

272 thways for the chemical reaction of CO2 with basalt to produce stable and nontoxic (Ca(2+), Mg(2+), F

273 n influence the overall ability of fractured basalt to sequester carbon.

274 otope compositions reported for ocean island basalts to date.

275 als whose range in composition from picritic basalts to granitoids rivals that found on the Earth.

276 lution produced compositions from low-silica basalts to high-silica dacite in the Syrtis Major calder

277 Basalts to the west of the boundary display affinities t

278 hin the subducted crust, consistent with the basalt-to-eclogite transformation.

279 stment Strategy for Asthma in the Long Term (BASALT) trial was conducted by the Asthma Clinical Resea

280 hase assemblage expected to crystallize from basalt under lower-mantle conditions.

281 e stratigraphically tied to a specific flood basalt unit, strengthening the case for volcanic Hg as t

282 Here we report the structure of molten basalt up to 60 GPa by means of in situ X-ray diffractio

283 housand), than the canonical mid-ocean ridge basalt value of -6.0 per thousand.

284 constraints on the age and duration of flood basalt volcanism within the Central Atlantic Magmatic Pr

285 oincidence between this extinction and flood basalt volcanism, existing geochronologic dates have ins

286 The overall carbonation kinetics of the basalt was enhanced by a factor of ca. 40.

287 illing into 3.5-million-year-old subseafloor basalt, we demonstrated the presence of methane- and sul

288 ing phase equilibria modelling of the Coucal basalts, we confirm their suitability as TTG 'parents',

289 m to contain more water than mid-ocean-ridge basalts, we demonstrate that basalts associated with man

290 t lowland plains material may be composed of basalts weathered under submarine conditions or weathere

291 deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago.

292 If degassing of basalts were responsible for the rise in oxygen, it requ

293 gin of the Steens-Columbia River (SCR) flood basalts, which is presumed to be the onset of Yellowston

294 Glass tubes packed with grains of olivine or basalt with different grain sizes and compositions were

295 edicts a petrogenetic sequence for the flood basalt with sources of melt starting from the base of th

296 Malad Gorge, Idaho, a canyon system cut into basalt with three remarkably distinct heads: two with am

297 In modern environments, basalts with low Nb/Ta form by partial melting of subduc

298 Rocks are olivinerich basalts with varying degrees of dust and other coatings.

299 ive to 226Ra occur in normal mid-ocean ridge basalts, with the largest deficits in the most magnesium

300 epleted source for high 3He/4He ocean island basalts would resolve the apparent discrepancy in the re