Showing papers in "Lithos in 1996"

TL;DR: Gorgona Island, Colombia is remarkable not only because it contains the only Phanerozoic komatiites, but also because it has mafic to ultramafic lavas with a wide range of compositions, from moderately enriched to extremely depleted (relative to Bulk Earth) as mentioned in this paper.

TL;DR: A 3.1-3.3 Ga mid-Archean accretionary complex has been identified in the Cleaverville area, Pilbara granite-greenstone terrain, Western Australia, by using a well-defined duplex structure and by reconstructing the oceanic plate stratigraphy as mentioned in this paper.

TL;DR: In the S-type Warburton Granodiorite (Lachlan Fold Belt, Australia) as mentioned in this paper, microgranitoid enclaves in the Lachlan fold belt display a range in mineralogical and isotopic compositions.

TL;DR: In this paper, a review of three oceanic plateaus, Ontong Java, Kerguelen and the Caribbean/Colombian abducted plateau, is presented.

TL;DR: In this paper, pressure-temperature estimates on a group of well-equilibrated garnet pyroxenites from the Qilin locality, southeastern China have been used to construct the first detailed, locality-specific paleogeotherm for eastern China.

TL;DR: In this article, a suite of mid-ocean ridge basalts were recovered from the ridge axis between 43 °S and 46 °20′S of the southern Chile Ridge.

TL;DR: In this article, the authors focus on the origin of highly deformed, MORB-like greenstone belts that are underlain by tonalitic to trondhjemitic plutons and surrounded by metamorphosed, accretionary wedge-like sediments.

TL;DR: In this article, the authors proposed a mixing model for the formation of the Karamea Batholith in the South Island of New Zealand, which is consistent with the mixing model presented in this paper.

TL;DR: In this paper, C and O isotope studies of these types of carbonates have yielded information on the origin of the carbonates and indicated the following processes of formation that determined the δ13C and δ18O values of the Carbonates: 1) Crystallization of magmatic carbonate; 2) Assimilation of sedimentary carbonate by silicate magmas.

TL;DR: In this paper, the authors investigated changes in magma type with time, and interpreted in terms of parameters such as pressure, depth of melting and the nature of the source region (fertile/refractory and water content).

TL;DR: There are very few Archean alkaline rocks in Precambrian terrains as discussed by the authors, and the only known examples are 2.7 Ga trachytes and leucite phonolites from the Kirkland Lake region of Canada.

TL;DR: The Igaliko Nepheline-Syenite Complex of Gardar age (1300-1120 Ma) includes carbonatite, lamprophyre, basalt, trachybasalt, phonolite and rhyolite dykes as mentioned in this paper.

TL;DR: The Manaslu pluton belongs to the High Himalayan leucogranite belt and was emplaced at the top of the Tibetan Slab as mentioned in this paper. But the migmatites within the formation are not the remanants of a melting process from which the manaslu granite was derived.

TL;DR: In this paper, an early high-pressure eclogite facies stage has been identified in the garnet and clinopyroxene-bearing amphibolites of the Tatra Mountains, in the Variscan basement of the Western Carpathians, Slovakia.

TL;DR: The 2.9 Ga-old Forrestania greenstone belt is intermediate in character between typical > 3.0 Ga and ~ 2.7 Ga belts in containing both Al-depleted and Al-undepleted komatiites as discussed by the authors.

TL;DR: In this article, multi-grain dating of zircons from a pegmatite dyke in southwestern Sweden yield analyses which define a discordia with upper and lower intercept ages of 1510 ± 32 Ma and 631 ± 64 Ma respectively.

TL;DR: In this paper, minor magmatic intrusions (dykes and explosion pipes) of lamprophyric and carbonatitic compositions occur on several islands in the Gulf of Kandalaksha (White Sea, Kola Peninsula, Russia).

TL;DR: In this paper, the geochemical consequences of FCA are examined and compared to those of AFC, and the behavior of incompatible elements is identical during FCA and FCA, and ratios of these elements do not allow discrimination between the two processes.

TL;DR: The Wadi Haymiliyah section, in the Haylayn block (Semail ophiolite, Oman) displays an unusual plutonic sequence closely similar to those of supra-subduction zone harzburgitic ophiorites (Troodos sub-type) as mentioned in this paper.

TL;DR: The Vizien greenstone belt is one such belt and it contains four fault-bounded structural panels that preserve a long-lived record of continent-ocean interaction as discussed by the authors.

TL;DR: The contact zone between the Cobo Granite and Bordeaux Diorite Complex of Guernsey (Channel Islands, UK) displays numerous features which result from the interaction of these two penecontemporaneously emplaced intermediate to felsic magmas.

TL;DR: In this article, the authors show that the fluid inclusions preserved in omphacite were formed by low-pressure re-equilibration of a fluid presumably trapped at eclogite-facies conditions.

TL;DR: In this article, a review of Cretaceous plateaux in the eastern Indian Ocean suggests that certain geochemical-isotopic criteria (e.g. positive Nb anomalies relative to primitive mantle) employed by petrologists to identify modern oceanic plateau lavas are of little practical use in distinguishing ancient plateau lava from arc and volcanic rifted margin basalts.

TL;DR: A-type affinities consistent with magma production during intracratonic rifting in the Willyama Supergroup in the Broken Hill Block have been investigated in this article.

TL;DR: In this paper, a petrographic, geochemical and isotopic (Sr, Nd and Pb) study was conducted on peridotites (Type Iα: harzburgite/clinopyroxene-poor Iherzolite and Type Iβ: dunite), 2-pyroxenes-spinel bearing ultrabasic and basic xenoliths [Type IIa: clinopyroxen-rich IHERZolite, wehrlite, (± olivine ± plagioclase) websterite,

TL;DR: In this paper, two sources of fluid are proposed for vein and ore formation: a local metamorphic fluid and a mixed ore fluid with δ18O and δD values in the range of 8.9 to 12.5 per mil and −87 to −90 per mil, respectively.

TL;DR: In this article, oxygen and carbon isotope ratios of whole rock powders and mineral separates from eclogites and granulites have been measured, indicating open system and locally heterogeneous fluid behavior.

TL;DR: In the case of the Gfohl gneisses from the Moldanubian of the Czech Republic, the authors of as discussed by the authors made a distinction between prograde and decompressional features in these rocks.

TL;DR: The newly discovered Umu Volcanic Field lies some 170 km west of Easter Island and covers an area of 1700 km2 as mentioned in this paper, which consists of two elongated ridges with three distinct peaks; photographic observations and dredge sampling indicate young volcanic activity.