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2005
van Zuilen, MA, Mathew K, Wopenka B, Lepland A, Marti K, Arrhenius G.  2005.  Nitrogen and argon isotopic signatures in graphite from the 3.8-Ga-old Isua Supracrustal Belt, Southern West Greenland. Geochimica Et Cosmochimica Acta. 69:1241-1252.   10.1016/j.gca.2004.08.033   AbstractWebsite

The problems involved with,the interpretation of carbon isotopes as indicators for early life in highly metamorphosed early Archean rocks have prompted the search for additional chemical and isotopic biomarkers. Here we report an attempt to identify the origin of carbonaceous matter in the 3.8 Ga old Isua Supracrustal Belt in southern West Greenland by measuring the concentration and isotopic composition of a trapped nitrogen component. Stepped-combustion/pyrolysis-mass spectrometry of carbonaceous matter in several rock samples revealed three different reservoirs of trapped nitrogen: (1) nitrogen associated with a very small amount of reactive carbonaceous material, (2) nitrogen intercalated in graphite, correlated with intercalated radiogenic argon, (3) nitrogen strongly retained at defects or chemically bound in the graphite structure. The delta(15)N of nitrogen associated with reactive carbonaceous matter (ca. +6 parts per thousand) overlaps with that of average Phanerozoic sedimentary organic matter, and is believed to be part of nonindigenous post-metamorphic biologic material. In situ Raman spectroscopy confirmed the high degree of crystallinity of the metamorphosed indigenous carbonaceous material, and this material is further referred to as graphite. Graphite interpreted as epigenetic (associated with Mg,Mn-siderite in metacarbonates) contains a very small strongly retained nitrogen component with a low delta(15)N ratio (-3 to -1 parts per thousand). This range overlaps with values that are typically found in Archean kerogens, but also those of a metamorphically emplaced inorganic basaltic source. Geological constraints suggest that this graphite incorporated nitrogen from surrounding metabasaltic rocks. Graphite interpreted as syngenetic and biogenic found in a turbidite deposit is relatively similar to this Mg,Mn-siderite-derived graphite, based on degree of graphite crystallinity, amount of trapped radiogenic argon, low nitrogen concentration and delta(15)N signature. We conclude that nitrogen concentration and its isotope ratio in graphite cannot be used conclusively as a biomarker in these rocks from the highly metamorphosed Isua Supracrustal Belt. Copyright (c) 2005 Elsevier Ltd.

Lepland, A, van Zuilen MA, Arrhenius G, Whitehouse MJ, Fedo CM.  2005.  Questioning the evidence for Earth's earliest life - Akilia revisited. Geology. 33:77-79.   10.1130/g20890.1   AbstractWebsite

It has been argued that apatite crystals containing inclusions of isotopically light graphite in a quartz-pyroxene rock from the island of Akilia, southwest Greenland, represent the earliest (older than 3.85 Ga) traces of life on Earth. Although the age and protolith of this rock have been subjects of vigorous discussions, the occurrence of isotopically light graphite inclusions in Akillia apatite has so far not been debated in the literature. We present here the results of petrographic analysis of 17 different Akilia samples, including the actual sample (G91-26) used in the original study. Our finding that none of the apatite crystals in these samples contain graphite inclusions indicates that the Akilia apatite has no bearing on claims pertaining to a past record of life on Earth.

2003
van Zuilen, MA, Lepland A, Teranes J, Finarelli J, Wahlen M, Arrhenius G.  2003.  Graphite and carbonates in the 3.8 Ga old Isua Supracrustal Belt, southern West Greenland. Precambrian Research. 126:331-348.   10.1016/s0301-9268(03)00103-7   AbstractWebsite

We present a systematic study of abundance, isotopic composition and petrographic associations of graphite in rocks from the ca. 3.8 Ga Isua Supracrustal Belt (ISB) in southern West Greenland. Most of the graphite in the ISB occurs in carbonate-rich metasomatic rocks (metacarbonates) while sedimentary units, including banded iron formations (BIFs) and metacherts, have exceedingly low graphite concentrations. Regardless of isotopic composition of graphite in metacarbonate rocks, their secondary origin disqualifies them from providing evidence for traces of life stemming from 3.8 Ga. Recognition of the secondary origin of Isua metacarbonates thus calls for reevaluation of earlier interpretations that suggested the occurrence of 3.8 Ga biogenic graphite in these rocks. Thermal decomposition of siderite; 6FeCO(3) = 2Fe(3)O(4) + 5CO(2) + C, is the process seemingly responsible for the graphite formation. The cation composition (Fe, Mg, Mn, and Ca) of the carbonate minerals, carbon isotope ratios of carbonates and associated graphite and petrographic assemblages of a suite of metacarbonates support the conclusion that multiple pulses of metasomatism affected the ISB, causing the deposition of Fe-bearing carbonates and subsequent partial disproportionation to graphite and magnetite. Equilibrium isotope fractionation between carbonate and graphite in the rocks indicates peak metamorphic temperatures between 500 and 600degreesC, in agreement with other estimates of metamorphic temperature for the ISB. Published by Elsevier B.V.

Arrhenius, GO.  2003.  Crystals and life. Helvetica Chimica Acta. 86:1569-1586.   10.1002/hlca.200390135   AbstractWebsite

The record of life's emergence on Earth has been thoroughly obliterated by the remelting and turnover of the crust, soggy and pliable from the water, retained by the planet's gravitational field. Provided that life existed on a smaller body such as Mars with an arrested crustal evolution, a protected sedimentary record there may give clues to the decisive events in the first 500 million years in the history of our solar system. Until such records become available, we have in our guesswork to rely on laboratory constructions that need to satisfy the demands both of chemical feasibility and environmental boundary conditions. The combination leaves few survivors among competing hypotheses. As life entails a decrease in entropy and creation of order, the origin and propagation of crystalline order has become a guiding theoretical concept. Recognizing Jack Dunitz's fundamental contribution to this field of knowledge, I wish to dedicate my modest discourse to this great scientist upon his scoring of the fourth significant time mark on the staff of life.

2002
Lepland, A, Arrhenius G, Cornell D.  2002.  Apatite in early Archean Isua supracrustal rocks, southern West Greenland: its origin, association with graphite and potential as a biomarker. Precambrian Research. 118:221-241.   10.1016/s0301-9268(02)00106-7   AbstractWebsite

Rare earth element (REE) abundances in individual apatite crystals in banded iron formations (BIFs), metacherts, metacarbonates and mafic dykes in the Isua supracrustal belt (ISB) have been determined by laser ablation inductively coupled plasma mass spectrometry. The results together with petrographic observations on the distribution of graphite have been used to track the origin of the different compositional types of apatite and to evaluate the potential, proposed in earlier studies, for use of the apatite-graphite association as a biomarker. The chondrite-normalized distribution patterns of apatite in metasedimentary BIFs and metacherts fall into three groups. Relatively flat profiles with distinct positive Eu anomaly are interpreted as characterizing sedimentary (diagenetic) apatite that carry the REE signature of the Archean ocean. Secondary apatite in Isua metasdiments with either middle REE enriched profiles or with light REE depleted profiles is interpreted to have crystallized from percolating carbonate-rich metasomatic fluids or from fluids derived from cross-cutting mafic dykes, respectively. The occurrence together of these different genetic types of apatite with distinct REE signatures within cm-scale samples shows the immobility of REE in preexisting apatite during metamorphic episodes. Apatite crystals in Isua rocks of uncontested chemical sedimentary origin (BIF and metachert samples) do not have graphite inclusions or coatings. Graphite inclusions and coatings on the other hand characterize apatite in secondary metacarbonate rocks. In these rocks graphite is produced by thermal-metamorphic reduction of carbonate ion, derived from dissociation of the metasomatic ferrous carbonate where iron serves as electron donor, oxidizing to form magnetite. In view of the non-sedimentary, metasomatic origin of Isua metacarbonates and the abiogenic source of graphite, the apatite-graphite assemblage can not be considered as a biomarker and does not provide information on early Archean life in the ISB. (C) 2002 Elsevier Science B.V. All rights reserved.

2000
Arrhenius, G, Lepland A.  2000.  Accretion of Moon and Earth and the emergence of life. Chemical Geology. 169:69-82.   10.1016/s0009-2541(00)00333-8   AbstractWebsite

The discrepancy between the impact records on the Earth and Moon in the time period, 4.0-3.5 Ga calls for a re-evaluation of the cause and localization of the late lunar bombardment. As one possible explanation, we propose that the time coverage in the ancient rock record is sufficiently fragmentary, so that the effects of giant, sterilizing impacts throughout the inner solar system, caused by marauding asteroids, could have escaped detection in terrestrial and Martian records. Alternatively, the lunar impact record may reflect collisions of the receding Moon with a series of small, original satellites of the Earth and their debris in the time period about 4.0-3.5 Ga. The effects on Earth of such encounters could have been comparatively small. The location of these tellurian moonlets has been estimated to have been in the region around 40 Earth radii. Calculations presented here, indicate that this is the region that the Moon would traverse at 4.0-3.5 Ga, when the heavy and declining lunar bombardment took place. The ultimate time limit for the emergence of life on Earth is determined by the effects of planetary accretion - existing models offer a variety of scenarios, ranging from low average surface temperature at slow accretion of the mantle, to complete melting of the planet followed by protracted cooling. The choice of accretion model affects the habitability of the planet by dictating the early evolution of the atmosphere and hydrosphere. Further exploration of the sedimentary record on Earth and Mars, and of the chemical composition of impact-generated ejecta on the Moon, may determine the choice between the different interpretations of the late lunar bombardment and cast additional light on the time and conditions for the emergence of life. (C) 2000 Elsevier Science B.V. All rights reserved.

Pitsch, S, Krishnamurthy R, Arrhenius G.  2000.  Concentration of simple aldehydes by sulfite-containing double-layer hydroxide minerals: Implications for biopoesis. Helvetica Chimica Acta. 83:2398-2411.   10.1002/1522-2675(20000906)83:9<2398::aid-hlca2398>3.0.co;2-5   AbstractWebsite

Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple. uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.

1999
Krishnamurthy, R, Pitsch S, Arrhenius G.  1999.  Mineral induced formation of pentose-2,4-bisphosphates. Origins of Life and Evolution of the Biosphere. 29:139-152.   10.1023/a:1006540518676   AbstractWebsite

Formation of rac.-pentose-2,4-bisphosphates is demonstrated, starting from glycolaldehyde phosphate and glyceraldehyde-2-phosphate, and induced by mixed valence double layer metal hydroxide minerals, The reactions proceed from dilute aqueous reactant solutions (1.5 mM) at near neutral pH. Conditions have been established, where ribose-2,4-bisphosphate is the major product (similar to 48%) among the pentose-2,4-bisphosphates, which are formed with up to 25% yield.

Mojzsis, SJ, Harrison TM, Arrhenius G, McKeegan KD, Grove M.  1999.  Origin of life from apatite dating? Reply Nature. 400:127-128.   10.1038/22035   AbstractWebsite
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Arrhenius, G, Bada JL, Joyce GF, Lazcano A, Miller S, Orgel LE.  1999.  Origin and ancestor: Separate environments. Science. 283:792-792. AbstractWebsite
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Krishnamurthy, R, Arrhenius G, Eschenmoser A.  1999.  Formation of glycolaldehyde phosphate from glycolaldehyde in aqueous solution. Origins of Life and Evolution of the Biosphere. 29:333-354.   10.1023/a:1006698208873   AbstractWebsite

Amidotriphosphate (0.1 M) in aqueous solution at near neutral pH in the presence of magnesium ions (0.25 M) converts glycolaldehyde (0.025 M) within days at room temperature into glycolaldehyde phosphate in (analytically) nearly quantitative yields (76% in isolated product). This robust phosphorylation process was observed to proceed at concentrations as low as 30 mu M glycolaldehyde and 60 mu M phosphorylation reagent under otherwise identical conditions. In sharp contrast, attempts to achieve a phosphorylation of glycolaldehyde with cyclotriphosphate ('trimetaphosphate') as phosphorylating reagent were unsuccessful. Mechanistically, the phosphorylation of glycolaldehyde with amidotriphosphate is an example of intramolecular delivery of the phosphate group.

1998
De Graaf, RM, Visscher J, Xu Y, Arrhenius G, Schwartz AW.  1998.  Mineral catalysis of a potentially prebiotic aldol condensation. Journal of Molecular Evolution. 47:501-507.   10.1007/pl00006406   AbstractWebsite

Minerals may have played a significant role in chemical evolution. In the course of investigating the chemistry of phosphonoacetaldehyde (PAL), an analogue of glycolaldehyde phosphate, we have observed a striking case of catalysis by the layered hydroxide mineral hydrotalcite ([Mg2Al(OH)(6)] [Cl.nH(2)O]). In neutral or moderately basic aqueous solutions, PAL is unreactive even at a concentration of 0.1 M. In the presence of a large excess of NaOH (2 M), the compound undergoes aldol condensation to produce a dimer containing a C3-C4 double-bond. In dilute neutral solutions and in the presence of the mineral, however, condensation takes place rapidly, to produce a dimer which is almost exclusively the C2-C3 unsaturated product.

Mojzsis, SJ, Arrhenius G.  1998.  Phosphates and carbon on Mars: Exobiological implications and sample return considerations. Journal of Geophysical Research-Planets. 103:28495-28511.   10.1029/98je02141   AbstractWebsite

Much of the surface of Mars may preserve chemical information contained in rocks from the Noachian era, with ages that overlap the correspondingly earliest Archean geological history of the Earth, or from before around 3800 Ma (Ma = 1 x 10(6) years). Metabolically sophisticated life, which utilized phosphate and carbon and was capable of fractionating carbon isotopes, was apparently present already on Earth by similar to 3800 Ma, or within 600 Ma after the formation of the planet. An early appearance of life on Earth opens the strong possibility for a similarly early and rapid emergence of life on planet Mars. This hypothesis remains within the realm of plausibility so long as it can be established that liquid water and energy sources were available there for inchoate life, and that the life that emerged reached a level of complexity which could be recognized by its chemical, and perhaps morphological remains. Hypotheses to be used in the search for an ancient Martian biosphere from future sample return missions are testable by examining the record of life in ancient terrestrial sedimentary rocks, including those that contain rare and recognizable "physical" microfossils ("morphofossils" identified on the basis of their shape alone) and stable, authigenic biominerals which include carbonaceous matter having characteristically fractionated carbon isotope signatures (here termed "chemofossils"). Prior to sample return, these tests can be applied to the mineral associations of the SNC meteorites, a group of meteorites believed to have originated on Mars. Recent claims of a biological origin for secondary minerals and their features as well as for trace organic compounds in the Martian meteorite ALH84001, are derived in part from the interpretation of putative "nanofossil" shapes and the nature of the associated mineral assemblage in small carbonate deposits of an igneous rock. Such igneous samples would not normally be the best candidate to search for evidence of past life, even on Earth. Investigations of these mineral occurrences in the Martian meteorites and of the oldest geological records on Earth provide a useful framework for (1) using mineral phase relationships, (2) analytical data of stable carbon isotopic distributions, and (3) the problematic task of morphofossil interpretations, in the search for life via future sample return missions from the ancient surface of Mars.

1997
Arrhenius, G.  1997.  Carbon dioxide warming of the early Earth. Ambio. 26:12-16. AbstractWebsite

Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure.

Kolb, V, Zhang SB, Xu Y, Arrhenius G.  1997.  Mineral induced phosphorylation of glycolate ion - A metaphor in chemical evolution. Origins of Life and Evolution of the Biosphere. 27:485-503.   10.1023/a:1006582526535   AbstractWebsite

Bilateral surface-active minerals with excess positive charge concentrate glycolate and trimetaphosphate ion from 10(-3) m aqueous solution to half-saturation of the internal surface sites, and induce phosphorylation of glycolate ion in the mineral with trimetaphosphate, sorbed from 10(-2) m solution. By utilizing reactants from dilute solution at near neutral pH, and eliminating the need for participating organic nitrogen compounds, the reaction comprises several elements considered necessary for geochemical realism in models for molecular evolution.

Arrhenius, G, Sales B, Mojzsis S, Lee T.  1997.  Entropy and charge in molecular evolution - the case of phosphate. Journal of Theoretical Biology. 187:503-522.   10.1006/jtbi.1996.0385   AbstractWebsite

Biopoesis, the creation of life, implies molecular evolution from simple components, randomly distributed and in a dilute state, to form highly organized, concentrated systems capable of metabolism, replication and mutation. This chain of events must involve environmental processes that can locally lower entropy in several steps; by specific selection from an indiscriminate mixture, by concentration from dilute solution, and in the case of the mineral-induced processes, by particular effectiveness in ordering and selective reaction, directed toward formation of functional biomolecules. Numerous circumstances provide support for the notion that negatively charged molecules were functionally required and geochemically available for biopoesis. Sulfite ion may have been important in bisulfite complex formation with simple aldehydes, facilitating the initial concentration by sorption of aldehydes in positively charged surface active minerals. Berate ion may have played a similar, albeit less investigated role in forming charged sugar complexes. Among anionic species, oligophosphate ions and charged phosphate esters are likely to have been of even more wide ranging importance, reflected in the continued need for phosphate in a proposed RNA world, and extending its central role to evolved biochemistry. Phosphorylation is shown to result in selective concentration by surface sorption of compounds, otherwise too dilute to support condensation reactions. It provides protection against rapid hydrolysis of sugars and, by selective concentration, induces the oligomerization of aldehydes. As a manifestation of life arisen, phosphate already appears in an organic context in the oldest preserved sedimentary record. (C) 1997 Academic Press Limited.

Arrhenius, G, Baldridge KK, RichardsGross S, Siegel JS.  1997.  Glycolonitrile oligomerization: Structure of isolated oxazolines, potential heterocycles on the early earth. Journal of Organic Chemistry. 62:5522-5525.   10.1021/jo962185r   AbstractWebsite

A study of glycolonitrile polymerization has led to the isolation and characterization of two 2,5-dihydro-4-aminooxazoles, 4 and 5. Previous reports have misassigned these structures as s-triazines or pyrimidines, X-ray diffraction analysis of crystals of 4 and an acetylated oxazole derivative of 5 (6) confirm the proposed structures. Ab initio computations are used to assess the relative thermodynamic stability of three trimer isomers (an s-triazine, an aminohydroxypyrimidine, and an aminooxazoline), and the results indicate that 4 is a novel kinetic product. Mechanistic considerations rationalize kinetic oxazole formation over the more customary triazine or pyrimidine trimers.

Eiler, JM, Mojzsis SJ, Arrhenius G.  1997.  Carbon isotope evidence for early life. Nature. 386:665-665.   10.1038/386665a0   AbstractWebsite
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Mojzsis, SJ, Arrhenius G, McKeegan KD, Harrison TM, Nutman AP, Friend CRL.  1997.  Evidence for life on Earth before 3,800 million years ago (vol 384, pg 55, 1996). Nature. 386:738-738. AbstractWebsite
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1996
Arrhenius, G, Mojzsis S.  1996.  Extraterrestrial life: Life on Mars - Then and now. Current Biology. 6:1213-1216.   10.1016/s0960-9822(96)00698-7   AbstractWebsite

The recent claim to have discovered evidence of extraterrestrial life on a meteorite from Mars is not compelling, but the study nevertheless has useful heuristic value.

Mojzsis, SJ, Arrhenius G, McKeegan KD, Harrison TM, Nutman AP, Friend CRL.  1996.  Evidence for life on Earth before 3,800 million years ago. Nature. 384:55-59.   10.1038/384055a0   AbstractWebsite

IT is unknown when life first appeared on Earth. The earliest known microfossils (similar to 3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a long time to develop this degree of complexity, then the existence of life much earlier than this can be argued(1,2). But the known examples of crustal rocks older than similar to 3,500 Myr have experienced intense metamorphism, which would have obliterated any fragile microfossils contained therein. It is therefore necessary to search for geochemical evidence of past biotic activity that has been preserved within minerals that are resistant to metamorphism. Here we report ion-microprobe measurements of the carbon-isotope composition of carbonaceous inclusions within grains of apatite (basic calcium phosphate) from the oldest known sediment sequences-a similar to 3,800-Myr-old banded iron formation from the Isua supracrustal belt, West Greenland(35), and a similar formation from the nearby Akilia island that is possibly older than 3,850 Myr (ref, 3). The carbon in the carbonaceous inclusions is isotopically light, indicative of biological activity; no known abiotic process can explain the data. Unless some unknown abiotic process exists which is able both to create such isotopically light carbon and then selectively incorporate it into apatite grains, our results provide evidence for the emergence of life on Earth by at least 3,800 Myr before present.

Dickens, JE, Irvine WM, Ohishi M, Arrhenius G, Pitsch S, Bauder A, Muller F, Eschenmoser A.  1996.  A search for interstellar oxiranecarbonitrile (C3H3NO). Origins of Life and Evolution of Biospheres. 26:97-110.   10.1007/bf01809850   AbstractWebsite

We report a search in cold, quiescent and in 'hot core' type interstellar molecular clouds for the small cyclic molecule oxiranecarbonitrile (C3H3NO), which has been suggested as a precursor of important prebiotic molecules. We have determined upper limits to the column density and fractional abundance for the observed sources and find that, typically, the fractional abundance by number relative to molecular hydrogen of C3H3NO is less than a few times 10(-10). This limit is one to two orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOCH3 in well-studied hot cores. A number of astrochemical discoveries were made, including the first detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the first astronomical detections of some eight rotational transitions of CH3CH2CN, CH3CCH, and HCOOCH3. In addition, we found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which we were unable to assign.

1995
Braterman, PS, Arrhenius G, Hui S, Paplawsky W.  1995.  Preferential Uptake of Ammonium-Ions by Zinc Ferrocyanide. Origins of Life and Evolution of the Biosphere. 25:531-538.   10.1007/bf01582022   AbstractWebsite

The concentration of ammonia from dilute aqueous solution could have facilitated many prebiotic reactions. This may be especially true if this concentration involves incorporation into an organized medium. We have shown that (unlike iron(III) ferrocyanide) zinc ferrocyanide, Zn-2 Fe(CN)(6) . xH(2)O, preferentially takes up ammonium ions from 0.01 M NH4Cl to give the known material Zn-3(NH4)(2)[Fe(CN)(6)](2) . xH(2)O, even in the presence of 0.01M KCl. KCl alone gave Zn3K2[Fe(CN)(6)](2) . xH(2)O. Products were characterized by elemental (CHN) analysis and powder X-ray diffraction (XRD). We attribute the remarkable specificity for the ammonium ion to the open framework of the product, which offers enough space for hydrogen-bonded ammonium ions, and infer that other inorganic materials with internal spaces rich in water may show a similar preference.

Pitsch, S, Eschenmoser A, Gedulin B, Hui S, Arrhenius G.  1995.  Mineral Induced Formation of Sugar Phosphates 15. Chemistry of Alpha-Aminonitrile from the Zurich Group. Origins of Life and Evolution of the Biosphere. 25:297-334.   10.1007/bf01581773   AbstractWebsite

Glycolaldehyde phosphate, sorbed from highly dilute, weakly alkaline solution into the interlayer of common expanding sheet structure metal hydroxide minerals, condenses extensively to racemic aldotetrose-2,4-diphosphates and aldohexose-2,4,6-triphosphates. The reaction proceeds mainly through racemic erythrose-2,4-phosphate, and terminates with a large fraction of racemic altrose-2,4,6-phosphate. In the absence of an inductive mineral phase, no detectable homogeneous reaction takes place in the concentration- and pH range used. The reactant glycolaldehyde phosphate is practically completely sorbed within an hour from solutions with concentrations as low as 50 mu m; the half-time for conversion to hexose phosphates is of the order of two days at room temperature and pH 9.5. Total production of sugar phosphates in the mineral interlayer is largely independent of the glycolaldehyde phosphate concentration in the external solution, but is determined by the total amount of GAP offered for sorption up to the capacity of the mineral. In the presence of equimolar amounts of rac-glyceraldehyde-2-phosphate, but under otherwise similar conditions, aldopentose-2,4,-diphosphates also form, but only as a small fraction of the hexose-2,4,6-phosphates.

1994
Kuma, K, Usui A, Paplawsky W, Gedulin B, Arrhenius G.  1994.  Crystal-Structures of Synthetic 7-Angstrom and 10-Angstrom Manganates Substituted by Monovalent and Divalent-Catons. Mineralogical Magazine. 58:425-447.   10.1180/minmag.1994.058.392.08   AbstractWebsite

The crystal structures of synthetic 7 angstrom and 10 angstrom manganates, synthetic birnessite and buserite, substituted by mono- and divalent cations were investigated by X-ray and electron diffractions. The monoclinic unit cell parameters of the subcell of lithium 7 angstrom manganate, which is one of the best ordered manganates, were obtained by computing the X-ray powder diffraction data: a = 5.152 angstrom, b = 2.845 angstrom, c = 7.196 angstrom, beta = 103.08-degrees. On the basis of the indices obtained by computing the X-ray diffraction data of Li 7 angstrom manganate, monovalent Na, K and Cs and divalent Be, Sr and Ba 7 angstrom maganates were interpreted as the same monoclinic structure with beta = 100-103-degrees as that of Li 7 angstrom manganate, from their X-ray diffraction data. In addition, divalent Mg, Ca and Ni 10 angstrom manganates were also interpreted as the same monoclinic crystal system with beta = 90-94-degrees. The unit cell parameters, especially a, c and beta, change possibly with the type of substituent cation probably because of the different ionic radius, hydration energy and molar ratio of substituent cation to manganates. However, these diffraction data, except for those of Sr and Ba 7 angstrom and Ca and Ni 10 angstrom manganates, reveal only some parts of the host manganese structure with the edge-shared [MnO6] octahedral layer. On the other hand, one of the superlattice reflections observed in the electron diffractions was found in the X-ray diffraction lines for heavier divalent cations Sr and Ba 7 angstrom and Ca and Ni 10 angstrom manganates. The reflection presumably results from the substituent cation position in the interlayer which is associated with the vacancies in the edge-shared [MnO6] layer and indicates that the essential vacancies are linearly arranged parallel to the b-axis. Furthermore, the characteristic superlattice reflection patterns for several cations, Li, Mg, Ca, Sr, Ba and Ni, manganates were interpreted that the substituent cations are regularly distributed in the interlayer according to the exchange percentage of substituent cation to Na+. In contrast, the streaking in the a-direction observed strongly in the electron diffractions for heavier monovalent cations, K and Cs, manganates probably results from the disordering of their cations in the a-direction in the interlayer.