Despite the widespread use of geomorphic offset measurements for calculating earthquake probabilities, little attention has been paid to either the uncertainties in the interpretation of offset geomorphic features, or the effects of these uncertainties on fault models and estimates of seismic hazard. Interpretation of offsets along the San Andreas fault in the Carrizo Plain have been the basis of hypotheses of a strong Carrizo fault segment which regularly breaks in great earthquakes several centuries apart...

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The 2.8 Ma Chegem caldera, an 11x15 km ash-flow caldera located in the Caucasus Mountains, presents a unique opportunity to study silicic magma systems because of its combination of youth, exposure and simplicity. Rapid uplift and erosion in the region has exposed over 2 km of flatlying caldera fill, consisting of densely welded tuff (rhyolitic to...

The San Jose pluton, a 117-km^2 body of medium-grained biotite-hornblende tonalite in the foothills of the Sierra San Pedro Mártir, northern Baja California, Mexico, is one of the more westerly plutons in the Cretaceous Peninsular Ranges batholith. The pluton has a teardrop form in plan view, elongate north-south and outlined by commonly well-exposed contacts. To the north the outline is remarkably hemi-circular and concordant to isoclinally folded, highly stretched strata. Traced southward, the form becomes...

The San Jose pluton, a 117-km^2 body of medium-grained biotite-hornblende tonalite in the foothills of the Sierra San Pedro Mártir, northern Baja California, Mexico, is one of the more westerly plutons in the Cretaceous Peninsular Ranges batholith. The pluton has a teardrop form in plan view, elongate north-south and outlined by commonly well-exposed contacts. To the north the outline is remarkably hemi-circular and concordant to isoclinally folded, highly stretched strata. Traced southward, the form becomes...

The geology and structure of two crustal scale shear zones were studied to understand the partitioning of strain within intracontinental orogenic belts. Movement histories and regional tectonic implications are deduced from observational data. The two widely separated study areas bear the imprint of intense Late Mesozoic through Middle Cenozoic tectonic activity. A regional transition from Late Cretaceous-Early Tertiary plutonism, metamorphism, and shortening strain to Middle Tertiary extension and magmatism is preserved in each area, with...

The geology and structure of two crustal scale shear zones were studied to understand the partitioning of strain within intracontinental orogenic belts. Movement histories and regional tectonic implications are deduced from observational data. The two widely separated study areas bear the imprint of intense Late Mesozoic through Middle Cenozoic tectonic activity. A regional transition from Late Cretaceous-Early Tertiary plutonism, metamorphism, and shortening strain to Middle Tertiary extension and magmatism is preserved in each area, with...

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages,...

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages,...

Despite the widespread use of geomorphic offset measurements for calculating earthquake probabilities, little attention has been paid to either the uncertainties in the interpretation of offset geomorphic features, or the effects of these uncertainties on fault models and estimates of seismic hazard. Interpretation of offsets along the San Andreas fault in the Carrizo Plain have been the basis of hypotheses of a strong Carrizo fault segment which regularly breaks in great earthquakes several centuries apart...

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The Moses Rock dike is a well-exposed, four-mile long, kimberlite-bearing breccia intrusion in the east central Colorado Plateau, one of eight known kimberlite-bearing diatremes in the province. The dike occurs in gently dipping beds of the Permian Cutler Formation, 2 miles west of the Comb Ridge monocline in eastern Monument Valley, Utah. Contacts are little altered...

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The Moses Rock dike is a well-exposed, four-mile long, kimberlite-bearing breccia intrusion in the east central Colorado Plateau, one of eight known kimberlite-bearing diatremes in the province. The dike occurs in gently dipping beds of the Permian Cutler Formation, 2 miles west of the Comb Ridge monocline in eastern Monument Valley, Utah. Contacts are little altered...

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages,...

Part I. 18O/16O analyses were made on 355 samples in and around the 11 by 14 km Lake City caldera, which formed 23 m.y. ago in response to the eruption of the rhyolitic Sunshine Peak Tuff. All of the major lithologies and hydrothermal alteration facies were analyzed, and a detailed δ18O map was made of the caldera and its surroundings. Intracaldera facies Sunshine Peak Tuff consists of three members interbedded with landslide debris and megabreccias...

The Mono Basin of eastern California provides an ideal laboratory in which to study the interaction of volcanic and tectonic processes. The late Quaternary geological record of volcanic activity and range-front faulting is relatively complete in the basin. Range-front faults of the Sierra Nevada offset dateable late Pleistocene glacial moraines, thus affording the opportunity to estimate range-front slip rates. The first two chapters concern dating of moraines that are offset by range-front faults. In Chapter...

The Hackberry volcano in central Arizona, is a large dacitic volcano of late Miocene age. Most of the Hackberry Mountain area is underlain by Miocene volcanic rocks, primarily basalt and dacite. The oldest are a heterogeneous group of basalt flows, the Hickey Formation, erupted from local cinder cones. They were superseded by a homogeneous group of basalt flows, the Thirteenmile Rock Basalt, erupted from vents east of the area. Pyroclastics from the Hackberry volcano intertongue...

The Hackberry volcano in central Arizona, is a large dacitic volcano of late Miocene age. Most of the Hackberry Mountain area is underlain by Miocene volcanic rocks, primarily basalt and dacite. The oldest are a heterogeneous group of basalt flows, the Hickey Formation, erupted from local cinder cones. They were superseded by a homogeneous group of basalt flows, the Thirteenmile Rock Basalt, erupted from vents east of the area. Pyroclastics from the Hackberry volcano intertongue...

The San Bernardino Mountains have uplifted over the last few million years at the hub of structural systems along the southern San Andreas fault zone and represent an excellent opportunity to study the interplay between orogeny and transpressive strike-slip faulting. To attain a better understanding of the complex architecture of deformation in this range, I have constrained several basic kinematic aspects of its development. First, the timing and magnitude of rock uplift and exhumation of...

The San Jose pluton, a 117-km^2 body of medium-grained biotite-hornblende tonalite in the foothills of the Sierra San Pedro Mártir, northern Baja California, Mexico, is one of the more westerly plutons in the Cretaceous Peninsular Ranges batholith. The pluton has a teardrop form in plan view, elongate north-south and outlined by commonly well-exposed contacts. To the north the outline is remarkably hemi-circular and concordant to isoclinally folded, highly stretched strata. Traced southward, the form becomes...

The San Jose pluton, a 117-km^2 body of medium-grained biotite-hornblende tonalite in the foothills of the Sierra San Pedro Mártir, northern Baja California, Mexico, is one of the more westerly plutons in the Cretaceous Peninsular Ranges batholith. The pluton has a teardrop form in plan view, elongate north-south and outlined by commonly well-exposed contacts. To the north the outline is remarkably hemi-circular and concordant to isoclinally folded, highly stretched strata. Traced southward, the form becomes...

Annette, Gravina, Duke, and southern Prince of Wales Islands are underlain primarily by Cambrian (and perhaps Proterozoic) through Triassic volcanic, sedimentary, plutonic, and metamorphic rocks. These rocks belong to the Alexander terrane, which is a coherent tectonic fragment that underlies much of southeastern (SE) Alaska, the Saint Elias Mountains of British Columbia, Yukon, and eastern Alaska, and coastal regions of west-central British Columbia. Geologic mapping combined with U-Pb (zircon) geochronologic studies have delineated the major...

Despite the widespread use of geomorphic offset measurements for calculating earthquake probabilities, little attention has been paid to either the uncertainties in the interpretation of offset geomorphic features, or the effects of these uncertainties on fault models and estimates of seismic hazard. Interpretation of offsets along the San Andreas fault in the Carrizo Plain have been the basis of hypotheses of a strong Carrizo fault segment which regularly breaks in great earthquakes several centuries apart...

The San Jose pluton, a 117-km^2 body of medium-grained biotite-hornblende tonalite in the foothills of the Sierra San Pedro Mártir, northern Baja California, Mexico, is one of the more westerly plutons in the Cretaceous Peninsular Ranges batholith. The pluton has a teardrop form in plan view, elongate north-south and outlined by commonly well-exposed contacts. To the north the outline is remarkably hemi-circular and concordant to isoclinally folded, highly stretched strata. Traced southward, the form becomes...

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages,...

Can limb regeneration be induced? Few have pursued this question, and an evolutionarily conserved strategy has yet to emerge. This study reports a strategy for inducing regenerative response in appendages, which works across three species that span the animal phylogeny. In Cnidaria, the frequency of appendage regeneration in the moon jellyfish Aurelia was increased by feeding with the amino acid L-leucine and the growth hormone insulin. In insects, the same strategy induced tibia regeneration in...

The Gold Butte breakaway zone is the easternmost and oldest of the major Tertiary normal fault systems in the central Basin and Range province of the southwestern U.S. The normal faults of the breakaway zone crop out across the South Virgin Mountains (SVM), and define a narrow boundary zone between the Colorado Plateau and the highly extended central Basin and Range Province. Geochronologic data, including 40Ar/39Ar muscovite ages, (U-Th)/He apatite ages, and (U-Th)/Pb monazite ages,...