NWA 2700 and NWA 2977 Paired With NWA 773: NWA 2700 is a 31.7 gram stone consisting of small gabbro clasts plus regolith breccia matrix (see Figure 1). The olivine gabbro contains ~50 vol.% olivine (Fa29.3-34.7; FeO/MnO = 94), pigeonite (Fs2228.3Wo5.6-10; FeO/MnO = 52), augite (Fs13.2Wo38.5), plagioclase and minor maskelynite (An89), Ba-rich alkali feldspar (Or92An4, BaO up to 8.9 wt.%), Crspin...

Plagioclase crystal fragments and a block of anorthosite occur in small basaltic dykes on the Jos Plateau. The anorthosite is unusual, for the feldspar is labradoritic, but the interstitial mineralogy is granitic rather than basic, displaying granophyric intergrowths in places. The anorthosite is probably not an intermediate stage in fractionation from a basic parent magma towards granite, sinc...

Introduction: Dhofar 733 is a 98-g lunar meteorite collected in the Dhofar region of Oman in 2002 [1]. In the initial description [1], Dhofar 733 is described as an anorthositic granulitic breccia, one that is probably not paired with any other lunar meteorite on the basis of its unique texture and isolation from other lunar meteorites (the next closest lunar meteorite was found 22 km away). Th...

Introduction: North West Africa (NWA) 1500 is an olivine-rich achondrite that is currently classified as ungrouped, based on petrography and oxygen isotope ratios [1-2]. Although some petrographic characteristics of NWA 1500 suggest a relationship to the augitebearing ureilites, it shows a distinct thermal history (equilibration to much lower T) that rules out derivation from the ureilite paren...

[1] The basic features of the geomagnetic reversal chronology of the last 160 million years are well established. The relationship between this history and other features of the field, however, has been elusive. The determination of past field strength (paleointensity) is especially challenging. Commonly accepted results have come from analyses of bulk samples of lava. Historic lavas have been ...

We report a detailed petrography, mineral chemistry, and trace element study of MaTroc, a large calcium–aluminum-rich inclusion (CAI) (5 2.5 mm) of irregular triangular shape. The inclusion has a zonal structure: The core consists of a porous plagioclase–olivine–Ca-rich pyroxene intergrowth with subordinate apatite. Its texture is meta-gabbro-like, similar to other plagioclase–olivine inclusion...

Nearly a decade ago, Gorter (1) suggested that the Bedout basement high, offshore Western Australia, might represent an impact structure, in view of the site_s well-defined circular Bouguer anomaly and seismic reflection data indicating a possible ring syncline. Recently, Becker et al. (2), as part of the search for the cause or causes of the mass extinction that marks the Permian-Triassic (P-T...

late miocene–pliocene calc-alkaline volcanic rocks are exposed southeast of isfahan in the urumieh-dokhtar magmatic belt. volcanic rocks consist of lava flows and domes, chiefly basaltic andesites, andesites and dacites. minerals in the volcanic rocks exhibit degrees of disequilibrium features. plagioclase as dominant mineral in these rocks generally displays reverse and oscillatory zoning; sie...