The initial isotopic compositions of Nd and Sr in basalts from the Central Siberian Plateau and other major continental flood basalts are reported. The continental flood basalts appear to be the product of partial melting of mantle sources that consist of relatively primitive undifferentiated material and are clearly distinct from midocean ridge basalts, which sample mantle reservoirs that have...

a r t i c l e i n f o a b s t r a c t In the context of sample evidence alone, the high-alumina (HA) basalts appear to be an unique, and rare variety of mare basalt. In addition to their distinct chemistry, radiometric dating reveals these basalts to be among the oldest sampled mare basalts. Yet, HA basalts were sampled by four missions spanning a lateral range of ∼2400 km, with ages demonstrat...

We explore Fe/Mn and Nb/Ta ratios of basalts as potential tracers for differentiating melts of recycled mafic crustal lithologies from peridotitic melts. Trace elements and Fe/Mn ratios of the Mesozoic and Cenozoic basalts from East China were analyzed by ICP-MS. Low Nb/Ta ratios (15.4 ± 0.3 (2r, n = 45)), high Nb and Ta contents (60.1 and 4.01 ppm) and high Fe/ Mn ratios (64.7 ± 1.5 (2r, n = 4...

Apollo 14 (A-14) impact melt olivine vitrophyres (OVs), composed of olivine phenocrysts in an opaque glass matrix with minor amounts of pyroxene and plagioclase, are petrographically similar to pristine quenched A-14 high-alumina (high-Al) and Apollo 12 (A-12) basalts. Textural and chemical analyses have been conducted on olivines within impact melt and pristine mare basalt clasts from A-14 bre...

The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB) under one class i.e., as mid-oceanic ridge basalts (MORB). Hence, a method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB). We have applied Artificial Neur...

Abundant mafic and ultramafic rocks including basalts, komatiitic basalts, and peridotites occur in the Proterozoic Sibao Group, northern Guangxi Province, China. Whereas the basalts are generally pillow lavas, the komatiitic basalts are typically spinifex-textured and, in a few cases, show pyroxene accumulation associated with Ni Cu (PGE) sulfide deposits. The peridotites occur in the lower po...

Oxygen and iron isotope analyses of low-Ti and high-Timare basalts are presented to constrain their petrogenesis and to assess stable isotope variations within lunar mantle sources. An internally-consistent dataset of oxygen isotope compositions of mare basalts encompasses five types of low-Ti basalts from the Apollo 12 and 15 missions and eight types of high-Ti basalts from the Apollo 11 and 1...

Major, trace element, and Nd–Sr–Pb isotopic compositions of mantle xenolith-bearing Cenozoic basalts in southeastern China are measured to provide an insight into the nature of their mantle sources and processes. Application of a modified Ž . dynamic melting inversion DMI method presented here to SE China basalts suggests that Nushan and Fangshan basalts are formed by 4–11% partial melting of a...

Oceanic island basalts have a large range in dO values (4·5– INTRODUCTION 7·5‰) compared with the assumed primordial mantle values A 1996 conference on ‘shallow level processes in ocean (5·5–6·0‰) and with mid-ocean ridge basalts (5·7 ± 0·2‰). island magmatism’ drew attention to the controversy that Some Hawaiian tholeiitic basalts have low O values (4·6–5·2‰), is developing on the possible ext...