Frezchem A Chemical Thermodynamic Model For Aqueous Solutions At Subzero Temperatures

This report documents a FORTRAN version of the Spencer-Moller-Weare chemical thermodynamic model for aqueous electrolyte solutions at sub-zero temperatures (FREZCHEM). FREZCHEM is structured to predict the chemical composition and unfrozen water of aqueous solutions between -60 deg and +25 deg C at atmospheric pressure (0.101325 MPa). FREZCHEM includes two reaction pathways: freezing at variable temperature and fixed total water and evaporation at variable water and fixed temperature. Activity coefficients and the activity of water are calculated using the Pitzer equations, which are valid to high solution ionic strengths (approx. 20 mol k-1). Fifteen chloride and sulfate salts of sodium, potassium, calcium, and magnesium are included in the model. Predicted and experimental measurements of solute molalities and the unfrozen water fraction during sea water freezing are in good agreement. At -50 deg C, 0.3 % of sea water remains unfrozen with 99.7% of Na and 95.5% of Cl having precipitated into one of four salts. FREZCHEM should find many applications in physicochemical studies of aqueous solutions and freezing.

Written by two of the best US researchers in the field, this text investigates issues of astrobiological relevance in the context of cold aqueous planetary geochemistry. At the core of the technical chapters is the FREZCHEM model, initially developed over many years by one of the authors to quantify aqueous electrolyte properties and chemical thermodynamics at subzero temperatures. FREZCHEM is of huge relevance to scientists in a number of fields, including biogeochemists.

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This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

This book reviews advances in understanding of the past ca. two million years of Earth history - the Quaternary Period - in the United States. It begins with sections on ice and water - as glaciers, permafrost, oceans, rivers, lakes, and aquifers. Six chapters are devoted to the high-latitude Pleistocene ice sheets, to mountain glaciations of the western United States, and to permafrost studies. Other chapters discuss ice-age lakes, caves, sea-level fluctuations, and riverine landscapes. With a chapter on landscape evolution models, the book turns to essays on geologic processes. Two chapters discuss soils and their responses to climate, and wind-blown sediments. Two more describe volcanoes and earthquakes, and the use of Quaternary geology to understand the hazards they pose. The next part of the book is on plants and animals. Five chapters consider the Quaternary history of vegetation in the United States. Other chapters treat forcing functions and vegetation response at different spatial and temporal scales, the role of fire as a catalyst of vegetation change during rapid climate shifts, and the use of tree rings in inferring age and past hydroclimatic conditions. Three chapters address vertebrate paleontology and the extinctions of large mammals at the end of the last glaciation, beetle assemblages and the inferences they permit about past conditions, and the peopling of North America. A final chapter addresses the numerical modeling of Quaternary climates, and the role paleoclimatic studies and climatic modeling has in predicting future response of the Earth's climate system to the changes we have wrought.