La herencia de jacobinismo en la deducción fichteana del cuerpo propio y del derecho a la existencia. Metafísica y política en el Fundamento del derecho natural

En este trabajo procuro complementar los estudios sobre el Fundamento del derecho natural que sólo reconstruyen la deducción metafísica del cuerpo sin referencia a sus consecuencias sociales y económicas, y las interpretaciones puramente histórico-contextuales del derecho a la existencia, mostrando la relación íntima que Fichte establece entre estos dos momentos de su teoría

Reflexión y lenguaje. Perspectivas de la transformación pragmático-trascendental de la filosofía kantiana

El trabajo discute el papel del lenguaje en la tradición de la filosofía trascendental. En la primera parte, se muestra ante todo el carácter a-lingüístico de las categorías del pensamiento en la filosofía kantiana; se señalan luego las dificultades teóricas a las que conduce el carácter dualista de esta posición reflexiva y se reconstruye finalmente la solución de Fichte a estas aporías. En la segunda parte, se aborda y se discute la transformación de la filosofía kantiana propuesta por la pragmática trascendental centrándose, ante todo, en el carácter lingüístico de las categorías del conocimiento válido. Se intenta mostrar los riesgos teóricos de absolutizar el papel del lenguaje en el proceso cognoscitivo y se propone, a modo de conclusión, una distinción entre teoría del conocimiento kantiana y fundamentación fichteana del conocimiento

Alkali contents, Sr isotope and U-Th-Pb data for ocean crust vein minerals from DSDP Holes 27-261, 61-462A, and 72-516F

Cation exchange experiments (ammonium acetate and cation resin) on celadonite-smectite vein minerals from three DSDP holes demonstrate selective removal of common Sr relative to Rb and radiogenic Sr. This technique increases the Rb/Sr ratio by factors of 2.3 to 22 without significantly altering the age of the minerals, allowing easier and more precise dating of such vein minerals. The ages determined by this technique (Site 261 - 121.4+/-1.6 m.y.; Site 462A - 105.1+/-2.8 m.y.; Site 516F - 69.9+/-2.4 m.y.) are 34, 54 and 18 m.y. younger, respectively, than the age of crust formation at the site; in the case of site 462A, the young age is clearly related to off-ridge emplacement of a massive sill/flow complex. At the other sites, either the hydrothermal circulation systems persisted longer than for normal crust (10-15 m.y.), or were reactivated by off-ridge igneous activity. Celadonites show U and Pb contents and Pb isotopic compositions little changed from their basalt precursors, while Th contents are significantly lower. Celadonites thus have unusually high alkali/U,Th ratios and low Th/U ratios. If this celadonite alteration signature is significantly imprinted on oceanic crust as a whole, it will lead to very distinctive Pb isotope signatures for any hot spot magmas which contain a component of aged subducted recycled oceanic crust. Initial Sr isotope ratios of ocean crust vein minerals (smectite, celadonite, zeolite, calcite) are intermediate between primary basalt values and contemporary sea water values and indicate formation under seawaterdominated systems with effective water/rock ratios of 20-200.

Chemistry of zeolithe and clays from Central Kerguelen Plateau basalts

Ocean Drilling Program Leg 120 recovered basement samples that consisted of zeolite-facies metabasalts at Sites 747, 749, and 750 on the Kerguelen Plateau. These basalts were metamorphosed in the low to intermediate zones of the zeolite facies, as indicated by the presence of diagnostic zeolites and the absence of chlorite, epidote, prehnite, pumpellyite, and wairakite. Chabazite, natrolite, thompsonite, mesolite, stilbite, huelandite, and smectites occur as amygduloidal fillings in basalts from Holes 747C and 750B, whereas only stilbite, laumontite, and pure and mixed-layered smectites were identified in amygduloidal basalts from Hole 749C. In the lower sections of Hole 749C, only laumontite and mixed-layered smectites coexist. Based on calculations with published experimental phase equilibria, the absence of wairakite in basalts from Hole 749C and of laumontite in basalts from Holes 747C and 750B suggests that metamorphic temperatures did not exceed approximately 225° and 120°C, respectively. The presence of well-developed zeolite mineral assemblages and the absence of carbonate and clay mineral assemblages restricts XCO2 in the fluid to approximately <=0.0075. Low- to intermediate-zone zeolite-facies mineral assemblages in basalts from the Kerguelen Plateau can be accounted for by metamorphism in an active geothermal area such as present-day Iceland.