The RNA World is generally thought to have been an important link between purely prebiotic (>3.7 Ga) chemistry and modern DNA/protein biochemistry. One concern about the RNAWorld hypothesis is the geochemical stability of ribose, the sugar moiety of RNA. Prebiotic stabilization of ribose by solutions associated with borate minerals, notably colemanite, ulexite, and kernite, has been proposed as...

In orogens, pinpointing the timing of mineralization is often complex due to superimposition magmatic, metamorphic and tectonic events. Unravelling tectono-metamorphic evolution deformed terranes essential for understanding formation orogenic mineralization. Bossòst dome Pyrenean Axial Zone, undated stratabound Pb-Zn previously considered be SEDEX-like devoid evidence significant remobilization...

INTRODUCTION The redox state of sillimanite zone (650–700°C, 5–6 kbar) metasediments of the Barrovian type area, Scotland, was investigated The chemical and mineralogical evolution of the crust using estimates of metamorphic oxygen fugacity (fO2 ), sulfur fugacity during orogenesis is critically dependent upon the redox (fS2 ), and fluid chemistry based on new determinations of mineral state of...

Subduction zones modulate the chemical evolution of the Earth's mantle. Water and volatile elements in the slab are released as fluids into the mantle wedge and this process is widely considered to result in the oxidation of the sub-arc mantle. However, the chemical composition and speciation of these fluids, which is critical for the mobility of economically important elements, remain poorly c...

Tourmaline can be found as an accessory mineral in a variety of rocks including leucogranite, pegmatite, quartz veins, and metamorphiccountry rocks in Hajiabad-Dehgah area in SE of Boroujerd city. Tourmaline in pegmatites is coarse-grained, subhedral to euhedral, anddisplays strong to moderate pleochroic blue rimmed by olive green. In contrast, tourmalines from leucogranite, quartz-veins, and h...

The eclogite facies assemblage K-feldspar–jadeite–quartz in metagranites and metapelites from the SesiaLanzo Zone (Western Alps, Italy) records the equilibration pressure by dilution of the reaction jadeite+quartz=albite. The metapelites show partial transformation from a pre-Alpine assemblage of garnet (Alm63Prp26Grs10)–K-feldspar–plagioclase–biotite±sillimanite to the Eo-Alpine high-pressure ...