The age and origin of the quartz-amphibole-pyroxene (qap) gneiss from the island of Akilia, southern West Greenland, have been the subject of intense debate since the light C-isotope composition of graphite inclusions in apatite was interpreted to indicate the presence of Earth's earliest biological activity. Although this claim for biogenic relicts has been vigorously challenged, the possibili...

The study of short-lived, now extinct radionuclides offers constraints on the duration of planetesimal formation and on other processes and events, which took place in the early solar system. The relative chronometers based on the decay of 53Mn to 53Cr (T1/2 = 3.7 m.y.) and of 26Al to 26Mg (T1/2 = 0.73 m.y.) provide an adequate time resolution of at least 1 m.y. A calibration of these relative ...

Granitic rocks related to 1.18 to 1.13 Ga anorthosite-mangerite-charnockitegranite plutonism stitch three terranes in the southwestern Grenville Province (Adirondack Highlands–Morin terrane, Frontenac terrane, Elzevir terrane). Because of the refractory nature of zircon (Zrn), analysis of oxygen-isotope ratios of dated igneous zircon from these rocks allows calculation of δ18O values of origina...

in order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the etive igneous complex in west scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. calculated activities for water are lower than unity in the pelitic sample and extremely low i...

In order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the Etive igneous complex in west Scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. Calculated activities for water are lower than unity in the pelitic sample and extremely low i...

In the Makran area, a wide accretionary wedge is originated by north-dipping subduction of Neo-Tethyan oceanic lithosphere. The rear represented North Domain that consists an imbricate stack tectonic units derived from closure basin. This basin opened southward Eurasia continental margin during Early Cretaceous. Bajgan Complex interpreted as Paleozoic or older metamorphic basement representing ...

available online at http://meteoritics.org Late accretion and lithification of chondritic parent bodies: Mg isotope studies on fragments from primitive chondrites and chondritic breccias Anna K. SOKOL1, 3*, Addi BISCHOFF1, Kuljeet K. MARHAS2, Klaus MEZGER3, and Ernst ZINNER2 1Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany 2McDonnell Center for the Space Sciences and Ph...