Pilar Mata

On the role of microbes in the alteration of submarine basaltic glass: A TEM study

Abstract The alteration of submarine basaltic glass that has been attributed to microbial activity was investigated via transmission electron microscopy in order to document glass alteration and to understand the chemical reactions that bacteria could utilize. The features that were examined occur within fresh glass at the alteration front and consist of 0.1–2.3 μm patches or tubes of phyllosilicates rimmed by 0.1–0.3 μm wide zones of altered glass. The altered glass has lost significant Mg, Fe, Ca and Na, slight amounts of Al and Mn, and exhibits an order of magnitude increase of K. This incongruent dissolution occurred at neutral to acid pH and temperatures 100 fracture volumes), which may be important for the supply of nutrients for microbial activity.

Two-, three- and four-feldspar assemblages with hyalophane and celsian: Implications for phase equilibria in BaAl2Si2O8-CaAl2Si 2O8-NaAlSi3O8-KAlSi 3O8

The occurrences of natural coexisting feldspars including hyalophane and also celsian delineate two-, three- and possibly four-phase fields in the system BaAl2Si2O8—CaAl2Si2O8—NaAlSi3O8—KAlSi3O8. Hyalophane occurs with albite and microcline in a very low grade (anchizonal to epizonal) metasedimentary association from the Uppony Mountains, Hungary, and in Grenville marbles from Ontario. Analyses show very little Ba in albite and only limited Na in hyalophane. One marble from the garnet zone has albite (Ab95–98), oligoclase (An17Sl3Ab80), hyalophane (Cn65Sl3An2Ab9Or24) and celsian (Cn92Sl3An1Ab2Or2). The albite and oligoclase are complexly intergrown and may indicate unmixing during cooling. A marble in the sillimanite zone contains albite (Ab95–98Or2–3), oligoclase (An17An2Sl3Ab33Or24), hyalophane (Cn65Sl3An2Ab9Or24), and an inclusion of celsian (Cn67An1Sl2Ab2Or91) in an albite. Sanidine from the Peshtigo monzonite in Wisconsin unmixed to a symplectic perthite with barian microcline (Cn8–11An2Ab8–13Or75–80) and oligoclase (CnlAn18Ab79Or2). The former compositions of the ternary igneous feldspars (Cn3An9Ab46Or42, Cn1An18Ab69Or12) were obtained by reintegration. The Na content of hyalophane equilibrated with albite is correlated with metamorphic grade. Hyalophane has 5 ± 2 mol % Ab in very low-grade associations, 10 ± 3 mol % Ab in the greenschist facies, 16 ± 2 mol % Ab in the low to middle amphibolite facies, and 30 mol % Ab in the upper amphibolite to granulite facies even when not buffered with albite. The limited Na content of celsian equilibrated with albite in the greenschist facies is in striking disagreement with the narrow solvi obtained from unreversed experiments on the join BaAl2Si2O86-NaAlSi3O8. Up to 8 four-feldspar and 24 three-feldspar assemblages may be stable in the system BaAl2Si2O8-CaAl2Si2O8-NaAlSi3O8-KAlSi3O8. In contrast, the repeatedly observed and variably located discontinuities within zoned hyalophane grains may represent changes in the environment during mineral growth rather than internal miscibility gaps. Given its miscibility gaps with microcline and celsian, the name hyalophane is justified for intermediate feldspars near the Cn-Or join.

Integrando escalas y métodos LTER para comprender la dinámica global de un espacio protegido de montaña: el Parque Nacional de Ordesa y Monte Perdido

Bonache, J., de Mingo-Sancho, G., Serrada, J., Amengual, P., Perales, J., Martinez, R., Rodado, S., Albornos, E. 2016. Long-term monitoring and evaluation in Spanish National Parks Network. Ecosistemas 25(1): 31-48. Doi.: 10.7818/ECOS.2016.25-1.05 The Spanish National Parks Network, consisting of a selection of natural spaces containing a representative sample of the main existing natural systems in Spain, is a very appropriate setting for research and long-term monitoring, in which the rules protects and promotes the improvement of knowledge and its application to management. In this regard, the National Parks Agency develops, in collaboration with the Autonomous Communities and with specific Scientific advise, a Research Program and a Monitoring and Evaluation Plan of the National Parks Network, latter having programs of ecological, sociological monitoring and functional. The article briefly explains the various monitoring initiatives underway, with examples of outcomes in each: mapping of natural systems, productivity monitoring through remote sensing, monitoring plant health, common bird monitoring, studies of social perception etc. Future prospects and areas for improvement of long-term monitoring in the National Parks Network are explained taking into account the synergies with the LTER Network, which is useful for monitoring in National Parks, especially concerning the application of comparable protocols and information management.

Two-, three- and four-feldspar assemblages with hyalophane and celsian implications for phase equilibria in BaAl2Si2O8—CaAl2Si2O8—NaAlSi3O8—KAlSi3O8*Contribution No. 518 from the Mineralogical Laboratory, Department of Geological Sciences, The University of Michigan 48109–1063.

The occurrences of natural coexisting feldspars including hyalophane and also celsian delineate two-, three- and possibly four-phase fields in the system BaAl2Si2O8—CaAl2Si2O8—NaAlSi3O8—KAlSi3O8. Hyalophane occurs with albite and microcline in a very low grade (anchizonal to epizonal) metasedimentary association from the Uppony Mountains, Hungary, and in Grenville marbles from Ontario. Analyses show very little Ba in albite and only limited Na in hyalophane. One marble from the garnet zone has albite (Ab95–98), oligoclase (An17Sl3Ab80), hyalophane (Cn65Sl3An2Ab9Or24) and celsian (Cn92Sl3An1Ab2Or2). The albite and oligoclase are complexly intergrown and may indicate unmixing during cooling. A marble in the sillimanite zone contains albite (Ab95–98Or2–3), oligoclase (An17An2Sl3Ab33Or24), hyalophane (Cn65Sl3An2Ab9Or24), and an inclusion of celsian (Cn67An1Sl2Ab2Or91) in an albite. Sanidine from the Peshtigo monzonite in Wisconsin unmixed to a symplectic perthite with barian microcline (Cn8–11An2Ab8–13Or75–80) and oligoclase (CnlAn18Ab79Or2). The former compositions of the ternary igneous feldspars (Cn3An9Ab46Or42, Cn1An18Ab69Or12) were obtained by reintegration. The Na content of hyalophane equilibrated with albite is correlated with metamorphic grade. Hyalophane has 5 ± 2 mol % Ab in very low-grade associations, 10 ± 3 mol % Ab in the greenschist facies, 16 ± 2 mol % Ab in the low to middle amphibolite facies, and 30 mol % Ab in the upper amphibolite to granulite facies even when not buffered with albite. The limited Na content of celsian equilibrated with albite in the greenschist facies is in striking disagreement with the narrow solvi obtained from unreversed experiments on the join BaAl2Si2O86-NaAlSi3O8. Up to 8 four-feldspar and 24 three-feldspar assemblages may be stable in the system BaAl2Si2O8-CaAl2Si2O8-NaAlSi3O8-KAlSi3O8. In contrast, the repeatedly observed and variably located discontinuities within zoned hyalophane grains may represent changes in the environment during mineral growth rather than internal miscibility gaps. Given its miscibility gaps with microcline and celsian, the name hyalophane is justified for intermediate feldspars near the Cn-Or join.

Two-, three- and four-feldspar assemblages with hyalophane and celsian

The occurrences of natural coexisting feldspars including hyalophane and also celsian delineate two-, three- and possibly four-phase fields in the system BaAl2Si2O8—CaAl2Si2O8—NaAlSi3O8—KAlSi3O8. Hyalophane occurs with albite and microcline in a very low grade (anchizonal to epizonal) metasedimentary association from the Uppony Mountains, Hungary, and in Grenville marbles from Ontario. Analyses show very little Ba in albite and only limited Na in hyalophane. One marble from the garnet zone has albite (Ab95–98), oligoclase (An17Sl3Ab80), hyalophane (Cn65Sl3An2Ab9Or24) and celsian (Cn92Sl3An1Ab2Or2). The albite and oligoclase are complexly intergrown and may indicate unmixing during cooling. A marble in the sillimanite zone contains albite (Ab95–98Or2–3), oligoclase (An17An2Sl3Ab33Or24), hyalophane (Cn65Sl3An2Ab9Or24), and an inclusion of celsian (Cn67An1Sl2Ab2Or91) in an albite. Sanidine from the Peshtigo monzonite in Wisconsin unmixed to a symplectic perthite with barian microcline (Cn8–11An2Ab8–13Or75–80) and oligoclase (CnlAn18Ab79Or2). The former compositions of the ternary igneous feldspars (Cn3An9Ab46Or42, Cn1An18Ab69Or12) were obtained by reintegration. The Na content of hyalophane equilibrated with albite is correlated with metamorphic grade. Hyalophane has 5 ± 2 mol % Ab in very low-grade associations, 10 ± 3 mol % Ab in the greenschist facies, 16 ± 2 mol % Ab in the low to middle amphibolite facies, and 30 mol % Ab in the upper amphibolite to granulite facies even when not buffered with albite. The limited Na content of celsian equilibrated with albite in the greenschist facies is in striking disagreement with the narrow solvi obtained from unreversed experiments on the join BaAl2Si2O86-NaAlSi3O8. Up to 8 four-feldspar and 24 three-feldspar assemblages may be stable in the system BaAl2Si2O8-CaAl2Si2O8-NaAlSi3O8-KAlSi3O8. In contrast, the repeatedly observed and variably located discontinuities within zoned hyalophane grains may represent changes in the environment during mineral growth rather than internal miscibility gaps. Given its miscibility gaps with microcline and celsian, the name hyalophane is justified for intermediate feldspars near the Cn-Or join.