Volcanic arcs fed by rapid pulsed fluid flow through subducting slabs

At subduction zones, oceanic lithosphere that has interacted with sea water is returned to the mantle, heats up during descent and releases fluids by devolatilization of hydrous minerals. Models for the formation of magmas feeding volcanoes above subduction zones require largescale transport of these fluids into overlying mantle wedges(1-3). Fluid flow also seems to be linked to seismicity in subducting slabs. However, the spatial and temporal scales of this fluid flow remain largely unknown, with suggested timescales ranging from tens to tens of thousands of years(3-5). Here we use the Li-Ca-Sr isotope systems to consider fluid sources and quantitatively constrain the duration of subduction-zone fluid release at similar to 70 km depth within subducting oceanic lithosphere, now exhumed in the Chinese Tianshan Mountains. Using lithium-diffusion modelling, we find that the wall-rock porosity adjacent to the flowpath of the fluids increased ten times above the background level. We show that fluids released by devolatilization travelled through the slab along major conduits in pulses with durations of about similar to 200 years. Thus, although the overall slab dehydration process is continuous over millions of years and over a wide range of pressures and temperatures, we conclude that the fluids produced by dehydration in subducting slabs are mobilized in short-lived, channelized fluid-flow events.

A New Genus of Microteiid Lizard from the Caparao Mountains, Southeastern Brazil, with a Discussion of Relationships among Gymnophthalminae (Squamata)

A new genus and species of microteiid lizard is described based on a series of specimens obtained at Parque Nacional do Caparao (20 degrees 28'S, 41 degrees 49'W), southeastern Brazil, along the division line between the States of Minas Gerais and Espirito Santo. The new lizard occurs in isolated high-altitude, open, rocky habitats above the altitudinal lit-nits of the Atlantic forest. It is characterized by the presence of prefrontals, frontoparietals, parietals, interparietal, and occipital scales; ear opening and eyelid distinct; three pairs of genials; absence of collar; lanceolate and mucronate dorsal scales; six regular transverse and longitudinal series of smooth ventrals that are longer than wide, with the lateral ones narrower. Maximum parsimony (MP) and partitioned Bayesian (PBA) phylogenetic analyses based on morphological and molecular characters with all known genera of Gymnophthalminae (except for Scriptosaura) Plus Rhachisaurus recovered this new lizard in a clade having Colobodactylus and Heterodactylus as its closest relatives. Both analyses recovered the monophyly of Gymnophthalminae and Gymnophthalmini. The monophyly of the Heterodactylini received moderate support in MP analyses but was not recovered in PBA. To eliminate classification controversy between these results, the present concept of Heterodactylini is restricted to accommodate the new genus, Colobodactylus and Heterodactylus, and a new tribe Iphisiini is proposed to allocate Alexandresaurus, Iphisa, Colobosaura, Acratosaura, and Stenolepis. Current phylogenetic knowledge of Gymnophthalminae suggests that fossoriality and increase of body elongation arose as adaptive responses to avoid extreme surface temperatures, either cold or hot, depending on circumstances.

Anacroneuria (Plecoptera, Perlidae) from the Mantiqueira Mountains, Sao Paulo State, Brazil

Seven species of Anacroneuria Klapalek are considered; of these 4 were known, A. debilis (Pictet, 1841), A. flintorum Froehlich, 2002, A. toriba Froehlich, 2002 (the female is described herein), and A. vanini Froehlich, 2004. Three are new: A. mantiqueirae, A. simulans, and A. tabatae.

Kempnyia (Plecoptera) from the Mantiqueira Mountains of Brazil

Eight species of Kempnyia Klapalek were collected in the Mantiqueira Mountains at Campos do Jordao, of which six were known: K. colossica (Navas, 1934), K. flava Klapalek, 1916, K. neotropica (Jacobson and Bianchi, 1905), K. obtusa Klapalek, 1916, K. reichardti Froehlich, 1984 and K. tamoya Froehlich, 1984; two are new, K. pirata and K. tupinamba. One new synonymy is proposed. Comments are provided for all species from the area and a key to these species is presented.

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia /by P. A. Rydberg...

1917

Illustrations of the botany and other branches of the natural history of the Himalayan Mountains :and of the flora of Cashmere /by J. Forbes Royle.

v. 2 Plates

Illustrations of the botany and other branches of the natural history of the Himalayan Mountains :and of the flora of Cashmere /by J. Forbes Royle.

v. 1 Text

Notes on a collection of cold-blooded vertebrates from the Olympic Mountains, by S. E. Meek.

v.1:no.12(1899)

Catalogue of mammals from the Olympic Mountains, Washington, with descriptions of new species, by D. G. Elliot.

v.1:no.13(1899)

Preliminary descriptions of new rodents from the Olympic Mountains.

v.1:no.11(1899)

Birds of the Acary Mountains, southern British Guiana [by] Emmet R. Blake.

v.32:no.7(1950)