Vol. 321, Issue 4, 2021

Science Paper
Terrestrial Biomarker Isotope Records of Late Quaternary Climate and Source-To-Sink Sediment Transport Processes in Southwestern Taiwan
Queenie ChangMichael HrenAndrew T. LinClay TaborShun-Wen YuYvette EleyGregory Harris
Fluvial sediments are important archives of paleoenvironments. However, variations in sediment production and transport processes greatly influence sediment geochemistry and resultant interpretations of ancient conditions. Tectonically-active tropical regions are particularly...
Science Paper
Thermochemistry of Melilites I. Towards Resolving an Inconsistency in Nebular Condensation Calculations
Richard O. Sack
A thermodynamic model is formulated for (Ca,Na)2(Mg,Fe2+,Al,Fe3+)T1 (Al,Fe3+,Si\()_{2}^{\textbf{T2}}\)O7 melilites. It employs the compositional vertices: åkermanite (Ca2MgSi2O7, 1), gehlenite (Ca2Al2SiO7, 2), iron åkermanite (Ca2Fe2+Si2O7, 3), ferrigehlenite (Ca2\(\text{Fe}_{2}^{3\, + \,}\)SiO7, 4), sodium...
Science Paper
Silurian-Devonian Tectonic Evolution of Mid-Coastal Maine, U.S.A.: Details of Polyphase Orogenic Processes
David P. WestEmily M. PetermanJessica Chen
Detailed bedrock mapping, structural geology, meta-igneous whole rock geochemistry, and U-Pb geochronology from rocks sampled along a portion of a complexly deformed tectonic boundary between the Ordovician peri-Gondwanan Liberty-Orrington belt...