Areas ofvegetation mortality have been recognized in the upland forests of the Kaimai Ranges, North Island, New Zealand. The mortality is not confined to any particular vegetation type, but occurs above a critical altitude that differs at different points along the ranges. The mortality is episodic and has occurred at intervals over a period of several hundred years, with severe droughts implic...

Introduction: The High Resolution Stereo Camera (HRSC) onboard ESA's Mars Express (MEX) orbiter [1] has provided 12.5 m/pixel projected images for a north-south transect of the four major Tharsis shield volcanoes. These data provide an unprecedented opportunity to examine lava flows at high resolution with regional context. Our objective is to characterize late-stage effusive processes and iden...

Continental flood basalts and mid-ocean ridge (MOR) tholeiitic basalts have distinctly different 14 3 Ndf1 44 Nd which may permit a priori distinctwn between '"continental" and "oceanic" igneous rocks. Initial 14 3 NdJI 4 4 Nd of continental igneous rocks through time fall on a Sm/Nd evolution curve with chondritic REE abundance ratio. These observations indicate that many continental igneous r...

Introduction: The acquisition of image data from the Mars Odyssey THermal EMission Imaging System (THEMIS) and the European Space Agency’s Mars Express High Resolution Stereo Camera (HRSC) have enabled new observations, and in some cases interpretations, of small volcanic features in the Tharsis region of Mars. While image resolution limitations have traditionally hampered detailed inspection o...

PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/...

Results by Neukum et al. (2001) and Ivanov (2001) are combined with crater counts to estimate ages of Martian surfaces. These results are combined with studies of Martian meteorites (Nyquist et al., 2001) to establish a rough chronology of Martian history. High crater densities in some areas, together with the existence of a 4.5 Gyr rock from Mars (ALH84001), which was weathered at about 4.0 Gy...

Abstract An extensive deposit of agate occurs in Pedro González Island the Gulf Panama. Previous archaeological research showed that was exploited between 6200 and 5600 cal BP to make stone tools found at oldest known Preceramic human settlement Pearl archipelago. We constrain here origin geological context through a geochemical study island. show it includes primary volcanic breccias, lavas, t...

Abstract Traditionally, the strata of Luonie Valley, Dechang County, SW Sichuan, China, are considered to contain a suite felsic volcanic rocks (the Huili Group) that erupted after c. 1050 Ma. However, we report here new age constraints, elemental and Lu–Hf isotope geochemistry for different older basaltic agglomerate lava, tuff lava basalt from same area, which name Formation. New dating resul...

Over two hundred isolated outcrops of horizontally stratified, basaltic lava flows within the inner gorge of western Grand Canyon indicate that several natural “lava dams” blocked the flow of the Colorado River during the Pleistocene, resulting in the formation of several lakes within the canyon. The largest lake was 90 m above the high water level of present-day Lake Powell and backed up a dis...