Sinopsis de la Constitución Geológica de Cuba

En este trabajo se presenta una síntesis actualizada de la constitución e historia geológica de Cuba y sus territorios aledaños. Según el modelo geológico que aquí se propone, en la constitución geológica del territorio se reconocen dos niveles principales: el substrato plegado y el neoautóctono. Constituyen el substrato plegado un conjunto de rocas distintamente deformadas y metamorfizadas, cuya antigüedad se remonta del Jurásico Inferior-Medio al Eoceno Superior, aunque hay pequeños afloramientos del Neoproterozoico. Este conjunto lo integran fragmentos de estructuras propias del Caribe occidental y del Pacífico, originados sobre substrato continental y oceánico. Las unidades geológicas de naturaleza continental son segmentos de los antiguos márgenes continentales de Yucatán y las Bahamas, parcialmente cubiertos por cuencas de antepaís. Las unidades geológicas de naturaleza oceánica son relictos de antiguas cortezas oceánicas, y cuatro sistemas de arcos volcánicos, tres del Cretácico y uno del Paleógeno. Sobre las unidades oceánicas se desarrollaron cuencas sedimentarias postvolcánicas y transportadas (p i ggy back) de edad Campaniense superior al Eoceno Superior. El Neoautóctono está representado por varias generaciones de cuencas sedimentarias desarrolladas sobre el substrato plegado, que cubren como un tapete poco deformado las estructuras anteriores. El contraste principal entre el substrato plegado y el neoautóctono es que el primero incluye elementos de distinta procedencia, propios de las placas de Norteamérica, del Caribe y, probablemente, del Pacífico; en cambio, el neoautóctono representa la evolución de un segmento pasivo del margen meridional de la placa de Norteamérica, después que los integrantes del substrato plegado se acreccionaron a ella. Se discuten dos posibles modelos de la estructura interna del orógeno plegado cubano, y se adopta uno de éstos para desarrollar un esquema de la evolución geológica del Caribe.A synthesis of the historical geology and constitution of Cuba is here presented. In this context, Cuba can be differentiated into the foldbelt and the neoautochthonous. In the foldbelt, Early-Middle Jurassic to Late Eocene rocks, as well as some minor Neoproterozoic elements, are distinctly deformed and metamorphosed. They represent fragments of structures detached from the western Caribbean and Pacific realms. These are passive margin-foreland sections detached from the Maya block (Yucatan peninsula), parts of the Strait of Florida block (Bahamas); fragments of antique oceanic crusts and island arc segments, both of Cretaceous and Paleocene-Middle Eocene age. The neoautochthonous represent a set of several sedimentary basins of latest Eocene to Recent, that like a carpet, rest unconformably above the foldbelt. These rocks are slightly deformed and represent the latest evolution of Cuban archipelago. The main differences between the foldbelt and the neoautochthonous lies in the fact that the foldbeld encompasses elements detached from several old tectonic plates (North American, Caribbean and, probably, Pacific), while the neoautochthonous evo l ved entirely on a passive segment of the North American plate margin, after the acretionary process that lead to the formation of the foldbelt. Two possible interpretations of the structure of the foldbelt are discussed, and according one of those models, it is presented a set of evolutionary maps and cross sections of the Caribbean

Guerra y derecho en Colombia: el decisionismo político y los estados de excepción como respuesta a la crisis de la democracia

El artículo trata sobre la crisis del Estado democrático contemporáneo, y estudia para el caso colombiano la figura de los estados de excepción, planteando que su uso recurrente contribuye a dicha crisis. Se presentan las teorías de Carl Schmitt como el fundamento teórico de esta práctica, mostrando su vigencia en la Colombia de hoy. Se recurre también a la teoría sociopolítica de Boaventura de Sousa Santos y de Franz Neumann y Otto Kirchheimer. Se pretende mostrar cómo, a pesar de los límites y carencias del modelo liberal democrático, este debe ser perfeccionado y no abandonado dada su potencialidad emancipadora que no ha sido llevada hasta sus últimas consecuencias, lo que permitiría lograr una sociedad más justa y libre.The article talks about the crisis of the contemporary democratic State, and it studies the figure of the state of emergency in the Colombian case, outlining that its recurrent use contributes to this crisis. Carl Schmitt’s theories are presented as the theoretic foundation of this practice, showing its validity in present-day Colombia. It also recurs to the socio-political theory of Boaventura de Sousa Santos, Franz Neumann and Otto Kirchheimer. It pretends to show how, in spite of the limits and deficiencies of the democratic neo-liberal model, which should be perfected and not abandoned given its emancipation potential that has not been taken to its ultimate consequences, what would lead to a more just and free society

The Interpretation of Caribbean Paleogeography: Reply to Hedges

La hipòtesi de GMRlàndia (Iturralde-Vinent & MacPhee, 1999) especifica que una llengua de terra, capaç d'actuar com a via de dispersió per a organismes terrestres, va connectar les futures Antilles Majors amb la vorera del nord-oest de Sud Amèrica durant un període curt cap a la transició Eocè/Oligocè. Hedges (2001) ha criticat aquesta hipòtesi sota diferents prismes, i a aquest treball tractam de replicar algunes de les seves objeccions, tenint en compte l'evidència més recent que tenim sobre les següents tres qüestions: (1) Quant ha durat la presència dels ambients terrestres actuals de la conca del Carib? (2) Quines han estat les dates d'emergència més probables per a les illes que tenen aquests ambients? (3) Quin efecte tenen les corrents de superfície marines sobre la distribució dels objectes que suren a l'àrea del Carib? Primer, en contra del que diu Hedges, encara no hi ha evidència geològica per a donar suport a una continuïtat als ambients terrestres del Carib abans de fa 37 Ma. A llavors, la pretensió d'Hedges que com a mínim algunes entitats biòtiques haurien persistit in situ per períodes de més de 37 Ma (la data més primerenca suportada per tal evidència), com a minim a algunes de les illes actuals, encara no es pot mantenir sobre bases geològiques. Segon, l'esdeveniment d'importància decisiva en l'emergència de GMRlàndia no fou la baixada del nivell eustàtic de la mar, sinó l'aixecament d'lm arc insular tot seguint el final de la seva fase magmàtica. A llavors, notar, com Hedges fa, que l'emergència de GAARIàndia no va estar correlacionada amb una baixada identificable principal-encara que fos correcte- no és pertinent al problema plantejat. Ni ho són les incerteses de les datacions, tant de les baixades com de l' esdeveniment d'aixecament. Finalment, encara que el moviment de les corrents de superfície marines està afectat per la força de Coriolis, el vent és molt més important per al moviment dels objectes sobre la superfície. Experiments reals revelen que aquests moviments són significativament caòtics, cosa que condueix a que el transport passiu virtualment mai esdevindrà en línia recta. Com a resultat, encara que els objectes transportats pels rius de Sud Amèrica eventualment poden embarrancar a les costes del Carib, els temps de trànsit són probablement llargs. Aquest fet, tal volta més que qualsevol altre, condueix a que les llargues estades a la mar siguin un mètode improbable de dispersió exitosa per a moltes castes d'organismes. Òbviament, les investigacions geològiques i paleontològiques no poden falsar escenaris històrics, però poden subministrar termini ad qu.em per precisament el tipus d'esdeveniments en que els biogeògrafs insulars haurien d'estar interessats, tals com quan apareixen per primera vegada a una àrea ambients desitjables per organismes terrestres, i quins organismes (representats per les seves restes) eren els primers en disposar de l'avantatge d'aquestes noves terres.La hipòtesi de GMRlàndia (Iturralde-Vinent & MacPhee, 1999) especifica que una llengua de terra, capaç d'actuar com a via de dispersió per a organismes terrestres, va connectar les futures Antilles Majors amb la vorera del nord-oest de Sud Amèrica durant un període curt cap a la transició Eocè/Oligocè. Hedges (2001) ha criticat aquesta hipòtesi sota diferents prismes, i a aquest treball tractam de replicar algunes de les seves objeccions, tenint en compte l'evidència més recent que tenim sobre les següents tres qüestions: (1) Quant ha durat la presència dels ambients terrestres actuals de la conca del Carib? (2) Quines han estat les dates d' emergència més probables per a les illes que tenen aquests ambients? (3) Quin efecte tenen les corrents de superfície marines sobre la distribució dels objectes que suren a l'àrea del Carib? Primer, en contra del que diu Hedges, encara no hi ha evidència geològica per a donar suport a una continuïtat als ambients terrestres del Carib abans de fa 37 Ma. A llavors, la pretensió d'Hedges que com a mínim algunes entitats biòtiques haurien persistit in situ per períodes de més de 37 Ma (la data més primerenca suportada per tal evidència), com a minim a algunes de les illes actuals, encara no es pot mantenir sobre bases geològiques. Segon, l'esdeveniment d'importància decisiva en l'emergència de GMRlàndia no fou la baixada del nivell eustàtic de la mar, sinó l'aixecament d'lm arc insular tot seguint el final de la seva fase magmàtica. A llavors, notar, com Hedges fa, que l'emergència de GAARIàndia no va estar correlacionada amb una baixada identificable principal-encara que fos correcte- no és pertinent al problema plantejat. Ni ho són les incerteses de les datacions, tant de les baixades com de l' esdeveniment d'aixecament. Finalment, encara que el moviment de les corrents de superfície marines està afectat per la força de Coriolis, el vent és molt més important per al moviment dels objectes sobre la superfície. Experiments reals revelen que aquests moviments són significativament caòtics, cosa que condueix a que el transport passiu virtualment mai esdevindrà en línia recta. Com a resultat, encara que els objectes transportats pels rius de Sud Amèrica eventualment poden embarrancar a les costes del Carib, els temps de trànsit són probablement llargs. Aquest fet, tal volta més que qualsevol altre, condueix a que les llargues estades a la mar siguin un mètode improbable de dispersió exitosa per a moltes castes d'organismes. Òbviament, les investigacions geològiques i paleontològiques no poden falsar escenaris històrics, però poden subministrar termini ad quem per precisament el tipus d'esdeveniments en que els biogeògrafs insulars haurien d'estar interessats, tals com quan apareixen per primera vegada a una àrea ambients desitjables per organismes terrestres, i quins organismes (representats per les seves restes) eren els primers en disposar de l'avantatge d'aquestes noves terres.The GMRlandia hypothesis (Iturralde-Vinent & MacPhee, 1999) specifies that a landspan, capable of acting as a dispersal conduit for terrestrial organisms, connected the future Greater Antilles with the margin of northwestern South America for a short period around the time of the Eocene/Oligocene transition. Hedges (2001) has criticized this hypothesis on various grounds, and in this paper we seek to reply to several of his objections by considering the most recent evidence bearing on these three questions: (1) How long have the present land environments of the Caribbean basin been in existence? (2) What are the likeliest emergence dates for the islands supporting those environments? (3) What effect do sea-surface currents have on the distribution of flotsam in the Caribbean area? First, contra Hedges, there is still no geological evidence for continuity in Caribbean land envirorunents earlier than 37 Ma. Therefore, Hedges' claim that biotic entities on at least some of the present islands have persisted in situ for periods longer than 37 Ma (the earliest date supported by such evidence) still GUillot be sustained on geological grounds. Secondly, the event of overriding importance in the emergence of GMRlandia was not drawdown in eustatic sea level, but uplíft in the island arc following the termination of its magmatic phase. Therefore, noticing as Hedges does that the emergence of GMRlandia was not correlated with an identifiable major drawdown-even if correct-has no pertinence to the issue at hand. Neither do uncertainties in the dating of either drawdowns or the uplift event. Finally, although the movement of sea-surface currents is affected by the Coriolis force, wind is much more important for the motion of objects on the surface (flotsam). Actual experiments reveal that such motions are significantly chaotic, which means that passive transport will virtually never occur in a straight line. As a result, although objects carried by South American rivers may eventually wash up on Caribbean shores, transit times are likely to be long. This fact, perhaps more than any other, makes long seas journeys an improbable method of successful dispersal for many kinds of organisms. Among such organisms we count most land mammals, for a host of autecological and physiological reasons. For other kinds of organisms, including herps, different considerations may apply. Obviously, paleontological and geological investigations cannot falsify historical scenarios, but they can provide termini ad quem for precisely the kinds of events that island biogeographers should be interested in, such as when environments suitable for land organisms first appeared in an area, and what organisms (as represented by their remains) were the first to take advantage of these new lands.The GMRlandia hypothesis (Iturralde-Vinent & MacPhee, 1999) specifies that a landspan, capable of acting as a dispersal conduit for terrestrial organisms, connected the future Greater Antilles with the margin of northwestern South America for a short period around the time of the Eocene/Oligocene transition. Hedges (2001) has criticized this hypothesis on various grounds, and in this paper we seek to reply to several of his objections by considering the most recent evidence bearing on these three questions: (1) How long have the present land environments of the Caribbean basin been in existence? (2) What are the likeliest emergence dates for the islands supporting those environments? (3) What effect do sea-surface currents have on the distribution of flotsam in the Caribbean area? First, contra Hedges, there is still no geological evidence for continuity in Caribbean land envirorunents earlier than 37 Ma. Therefore, Hedges' claim that biotic entities on at least some of the present islands have persisted in situ for periods longer than 37 Ma (the earliest date supported by such evidence) still GUillot be sustained on geological grounds. Secondly, the event of overriding importance in the emergence of GMRlandia was not drawdown in eustatic sea level, but uplíft in the island arc following the termination of its magmatic phase. Therefore, noticing as Hedges does that the emergence of GMRlandia was not correlated with an identifiable major drawdown-even if correct-has no pertinence to the issue at hand. Neither do uncertainties in the dating of either drawdowns or the uplift event. Finally, although the movement of sea-surface currents is affected by the Coriolis force, wind is much more important for the motion of objects on the surface (flotsam). Actual experiments reveal that such motions are significantly chaotic, which means that passive transport will virtually never occur in a straight line. As a result, although objects carried by South American rivers may eventually wash up on Caribbean shores, transit times are likely to be long. This fact, perhaps more than any other, makes long seas journeys an improbable method of successful dispersal for many kinds of organisms. Among such organisms we count most land mammals, for a host of autecological and physiological reasons. For other kinds of organisms, including herps, different considerations may apply. Obviously, paleontological and geological investigations cannot falsify historical scenarios, but they can provide termini ad quem for precisely the kinds of events that island biogeographers should be interested in, such as when environments suitable for land organisms first appeared in an area, and what organisms (as represented by their remains) were the first to take advantage of these new lands

El uso del discurso de los derechos humanos por parte de los actores armados en Colombia: ¿Humanización del conflicto o estrategia de guerra?

En Colombia, los derechos humanos son principios normativos reconocidos por todos los grupos armados involucrados en el conflicto armado; sin embargo, en la práctica su violación se ha incrementado en las últimas décadas. Este artículo explora la manera en que las FARC, el ELN y las AUC entienden e incluyen en su discurso político los derechos humanos y el Derecho Internacional Humanitario, y pone de manifiesto la brecha que existe entre sus discursos y sus acciones. Los derechos humanos y el DIH se han convertido de esta manera en armas políticas dentro de la lógica de la guerra.El artículo considera el contexto más amplio en el que se desarrolla el conflicto armado colombiano para resaltar la dificultad que implica pasar de la retórica a la práctica de los derechos humanos. Se aborda así la manera en que se construyen relaciones sociales, lenguajes e identidades que reproducen la violencia, favorecen la exclusión y dificultan la apropiación del discurso de los derechos humanos. El artículo concluye con una serie de reflexiones sobre la posibilidad de que los derechos humanos recuperen su poder transformativo dentro del contexto colombiano y dejen de ser un discurso vaciado de contenido y manipulado dentro de la lógica de la guerra.The use of the human rights discourse by Colombian illegal armed groups: humanization of the armed conflict or strategy of war?In Colombia human rights are normative principles recognized by all the illegal groups involved in the armed conflict; nevertheless, their violation has increased during the last decades. This article explores the way in which the FARC, the ELN and the AUC understand human rights and Humanitarian International Law and include them in their political discourse, showing the distance that exists between their discourse and their actions. Thus, human rights have become political weapons within the logic of war.The article takes into consideration the wider context of the Colombian armed conflict in order to understand the difficulty of moving from rhetoric to practice regarding human rights. Thus, the article tackles the construction of social relations, languages and identities that reproduce violence, favor exclusion and hinder the appropriation of human rights. The article concludes with a series of reflections about the possibility of regaining the transformative power of human rights within the Colombian context, so that they are no longer manipulated within the logic of war

Caribbean paleogeography

95 p. : ill., maps (some col.) ; 26 cm.Includes bibliographical references (p. 59-72)."This paper presents a series of detailed paleogeographical analyses of the Caribbean region, beginning with the opening of the Caribbean basin in the Middle Jurassic and running to the end of the Middle Miocene. Three intervals within the Cenozoic are given special treatment: Eocene-Oligocene transition (35-33 Ma), Late Oligocene (27-25 Ma), and early Middle Miocene (16-14 Ma). While land mammals and other terrestrial vertebrates may have occupied landmasses in the Caribbean basin at any time, according to the interpretation presented here the existing Greater Antillean islands, as islands, are no older than Middle Eocene. Earlier islands must have existed, but it is not likely that they remained as such (i.e., as subaerial entities) due to repeated transgressions, subsidence, and (not incidentally) the K/T bolide impact and associated mega-tsunamis. Accordingly, we infer that the on-island lineages forming the existing (i.e., Quaternary) Antillean fauna must all be younger than Middle Eocene. The fossil record, although still very poor, is consistent with the observation that most land mammals lineages entered the Greater Antilles around the Eocene-Oligocene transition. Western Laurasia (North America) and western Gondwana (South America) were physically connected as continental areas until the mid-Jurassic, ca. 170 Ma. Terrestrial connections between these continental areas since then can only have occurred via landbridges. In the Cretaceous, three major uplift events, recorded as regional unconformities, may have produced intercontinental landbridges involving the Cretaceous Antillean island arc. The Late Campanian/Early Maastrichtian uplift event is the one most likely to have resulted in a landbridge, as it would have been coeval with uplift of the dying Cretaceous arc. However, evidence is too limited for any certainty on this point. The existing landbridge (Panamanian Isthmus) was completed in the Pliocene; evidence for a precursor bridge late in the Middle Miocene is ambiguous. We marshal extensive geological evidence to show that, during the Eocene-Oligocene transition, the developing northern Greater Antilles and northwestern South America were briefly connected by a "landspan" (i.e., a subaerial connection between a continent and one or more offshelf islands) centered on the emergent Aves Ridge. This structure (Greater Antilles + Aves Ridge) is dubbed GAARlandia. The massive uplift event that apparently permitted these connections was spent by 32 Ma; a general subsidence followed, ending the GAARlandia landspan phase. Thereafter, Caribbean neotectonism resulted in the subdivision of existing land areas. The GAARlandia hypothesis has great significance for understanding the history of the Antillean biota. Typically, the historical biogeography of the Greater Antilles is discussed in terms of whether the fauna was largely shaped by strict dispersal or strict continent-island vicariance. The GAARlandia hypothesis involves elements of both. Continent-island vicariance sensu Rosen appears to be excludable for any time period since the mid-Jurassic. Even if vicariance occurred at that time, its relevance for understanding the origin of the modern Antillean biota is minimal. Hedges and co-workers have strongly espoused over-water dispersal as the major and perhaps only method of vertebrate faunal formation in the Caribbean region. However, surface-current dispersal of propagules is inadequate as an explanation of observed distribution patterns of terrestrial faunas in the Greater Antilles. Even though there is a general tendency for Caribbean surface currents to flow northward with respect to the South American coastline, experimental evidence indicates that the final depositional sites of passively floating objects is highly unpredictable. Crucially, prior to the Pliocene, regional paleoceanography was such that current-flow patterns from major rivers would have delivered South American waifs to the Central American coast, not to the Greater or Lesser Antilles. Since at least three (capromyid rodents, pitheciine primates, and megalonychid sloths) and possibly four (nesophontid insectivores) lineages of Antillean mammals were already on one or more of the Greater Antilles by the Early Miocene, Hedges' inference as to the primacy of over-water dispersal appears to be at odds with the facts. By contrast, the landspan model is consistent with most aspects of Antillean land-mammal biogeography as currently known; whether it is consistent with the biogeography of other groups remains to be seen"--P. 3

New Tertiary fossils from Cuba and Puerto Rico.

30 p. : ill. (some col.) ; 26 cm.Includes bibliographical references (p. 25-30

Fluid flow in the subduction channel: Tremolite veins and associated blackwalls in antigoritite (Villa Clara serpentinite mélange, Cuba)

Exotic blocks of massive antigorite-serpentinite (antigoritite) document a deep-seated subduction channel in the Villa Clara serpentinite-matrix mélange, central Cuba. The petrological and geochemical characteristics of antigoritite allow distinguishing two types of rock: i) antigoritite and ii) dolomite-bearing antigoritite. Both types are intimately related in field exposures and represent deep peridotite infiltrated by H2O-CO2 fluid mixtures that triggered antigoritization and local carbonation. Fluid infiltration continued after antigoritization forming a vein network as a potential response to hydrofracturing that precipitated tremolitite in the veins and triggered fluid-antigoritite reaction forming blackwalls. The mineralogical and chemical zoning in the blackwalls (Atg + Chl + Tr adjacent to antigoritite and Chl + Tr adjacent to the tremolitite vein) attest for multi-step metasomatic processes during fluid-rock interaction characterized by advection of infiltrating fluid towards the blackwall and, possibly, by diffusion out of the blackwall towards the fluid-filled vein. Tentative thermodynamic modeling of the blackwall domain Atg + Chl + Tr points vein network formation at 400–500 °C and 5–10 kbar during exhumation in the subduction channel, suggesting the infiltration of deep-seated pressurized fluid that triggered hydrofracturing. The chemical compositions of antigoritites, veins and blackwalls indicate a LILE- and LREE-enriched fluid evolved from the subducting plate, while Srsingle bondNd isotope systematics are compatible with an external fluid composed of a mixture of fluids evolved from sediments and, probably to a lesser extent, altered oceanic crust.This research was funded by projects MICINN PID2019-105625RB-C21 (co-funded by Fondo Europeo de Desarrollo Regional, FEDER), Junta de Andalucía P20_00550, Catalonian project SGR 2014-1661 and the University of Granada. LD acknowledges PhD grant BES-2013-063205 of the Spanish Ministry of Economy and Competitiveness and scholarship of Fundació Universitària Agustí Pedro i Pons. Funding for open access charge: Universidad de Granada / CBUA

The Hatillo Limestone, Pueblo Viejo district, Dominican Republic: Marginal reef or impermeable cap?

The Hatillo Limestone and the underlying Los Ranchos Formation are exposed over an east-west distance of 100 km in the eastern Dominican Republic. The lowermost portion of the Hatillo Limestone in the Pueblo Viejo district contains a Late Lower Albian fossil assemblage including corals and rudist bivalves indicative of a near-shore reef environment. Diamond drilling in the Pueblo Viejo district and exposures in the open pits show that the Hatillo Limestone conformably overlies the Early Cretaceous Los Ranchos Formation. Volcanogenic massive sulfide beds, exposed in the Moore pit, provide evidence for an Early Cretaceous, syn-mineralization paleosurface. Altered and mineralized clasts in the epiclastic, sedimentary host-rock section at the Pueblo Viejo mine indicate that the ore deposits were open to erosion during hydrothermal alteration and mineralization. The Hatillo Limestone did not overlie the ore deposits during the mineralizing event and, consequently, could not have acted as an impermeable cap to ascending hydrothermal fluids. Intra-oceanic island arc volcanism (Los Ranchos Formation) overlapped at the Aptian-Albian boundary (112 Ma) with a marginal fringing reef (basal Hatillo Limestone). The marginal reef gradually gave way to deeper-water facies as Hatillo Limestone deposition progressed through the middle Albian. Low-angle reverse faulting, penetrative deformation, and metamorphic recrystallization affected the Hatillo Limestone as well as the Los Ranchos and Maimón formations during the Late Cretaceous. Deformation intensity and metamorphic grade progressed from incipient metamorphism in the Pueblo Viejo district to schists in the Maimón Formation to amphibolite near a faulted contact with the Loma Caribe peridotite