Showing papers by "University of California, Santa Barbara published in 1973"

Origin of Late Cenozoic Basins in Southern California: ABSTRACT

Abstract: Several sedimentary basins in southern California, within and south of the Transverse Ranges, display a history suggestive of a rhombochasmic origin Beginning in the early Miocene, segments of the continental margin at the soft and splintered border between the Pacific and Americas plates were apparently fragmented so that basins originated as irregular pull-aparts Basin walls were formed by both transform faults and by crustal stretching and dip-slip faulting Deep basin floors grew as a complex of volcanic rocks and sediments As basins enlarged, high-standing blocks are pictured as separating laterally from terranes that were originally adjacent Older rocks exposed around margins therefore cannot be extrapolated to depth within the basins Support for such a speculative model comes from accumulating understanding of the Salton trough This narrow graben is being pulled apart obliquely, with faults of the San Andreas system serving as transforms With widening, the walls sag and stretch, and margins are inundated by sedimentation that occurs simultaneously with deformation and volcanism in the basin floor The Los Angeles basin apparently started to form as a rhombic hole in the middle Miocene, with basin-floor volcanism accompanied and followed by voluminous sedimentation The Miocene "Topanga basin" in the western Santa Monica Mountains contains vast thicknesses of volcanic and sedimentary rocks that were laid down adjacent to high ground, from which sediments and huge detachment slabs were carried into a spreading hol Other basins that perhaps reveal stages in the history of crustal stretching, culminating in pull-aparts and rhombochasms, are parts of Ventura basin, Ridge basin, and several offshore depressions, including the Santa Barbara Channel End_of_Article - Last_Page 774------------

Digital lattice and ladder filter synthesis

Abstract: There is evidence that in addition to standard digital filter forms such as the direct, parallel, and cascade forms, digital lattice and ladder filters may play an important role in finite word length implementation problems. In this paper, techniques are developed in detail for efficiently synthesizing digital lattice and ladder filters from any stable direct form. In one form, a lattice filter canonic in terms of multiplies and delays is obtained. An internal scaling procedure is also introduced that will be of importance for optimizing one of the lattice forms for finite word length implementation.

Absolute motion parallax and the specific distance tendency

Abstract: In the absence of definitive cues’to distance, the perceived distance of an object will be in error in the direction of the object appearing at a distance of about 2 m from O. This tendency to perceive an object at a relatively near distance is termed the specific distance tendency (Gogel. 1969). Also, it has been found that an error in perceiving the distance of an object will result in an apparent movement of the object when the head is moved (Hay & Sawyer. 1969; Wallach, Yablick. & Smith. 1972). From these two results, it was expected that the direction of trie apparent movement of a stationary point of light resulting from head movement would vary predictably as a function of the physical distance of the point of light from O. This expectation was confirmed in an experiment in which both the perceived motion and perceived distance of the point of light were measured. The consequences of the study for the role of motion parallax in the perception of distance and for the reafference principle in the perception of object motion with head motion are discussed

Antidune and chute and pool structures in the base surge deposits of the Laacher See area, Germany

Abstract: Grey tuffs of late Pleistocene age form broad fans radiating from the Laacher See basin. They were derived from phreatomagmatic outbursts, and transported in turbulent pyroclastic flows, in contrast with the underlying white pumice tuffs of air fall origin. Flow origin of the grey tuffs is inferred from the well-bedded plane parallel to cross-bedded tephra characteristic of base surge deposits, and a variety of other sedimentary structures, as well as grain size distributions. We recognize a tentative sequence of five main kinds of dune structures or cross-bedded strata. With some reservations these may be compared with the high flow-regime alluvial bedforms produced experimentally in flumes. Most of the cross-bedded structures in the Laacher See deposits resemble antidunes, with steep stoss sides and very low-dipping lee sides. Upcurrent migration of antidune crests is dominant close to the source, but changes to downcurrent migration at greater distances, presumably because of decay in flow energy. The most spectacular cross-bedding is somewhat similar to chute and pool structures formed under experimental condition in alluvial flumes, but not recognized in ancient sedimentary rocks. We suggest that these structures of the Laacher See tuffs formed during deposition from phreatic pyroclastic flows of very high flow energy and high sediment concentration. The antidunes apparently formed at lesser flow velocity than chute and pool structures, although interpretation of velocity conditions by examination of the deposits is difficult because of other factors such as the cohesiveness of wet material erupted by explosive phreatic volcanic activity. The large wave lengths of the dune-like structures, however, suggest unusually high velocities. The Laacher See magmas were of phonolitic to tephritic composition, and may have erupted with greater explosive energy and in greater volume than comparable basaltic eruptions.

Fire and the nitrogen cycle in california chaparral.

Abstract: Analysis of soils from burned and unburned chaparral indicates that high nitrate concentrations following fire are due to the addition of ammonium and organic nitrogen in the ash. Inhibition of mineralization in unburned chaparral results in low nitrate concentrations. Fluctuations in the amount of soil nitrate in unburned chaparral are the direct result of foliar leaching.

Frameshift suppression: a nucleotide addition in the anticodon of a glycine transfer RNA.

Abstract: Strains of Salmonella typhimurium carrying the frameshift suppressor mutation, sufD, produce a glycine tRNA with the nucleotide quadruplet, CCCC, at the anticodon position, instead of the triplet, CCC, found in wildtype.

Slowly rotating relativistic stars: IX: Moments of Inertia of Rotationally Distorted Stars

Abstract: Equations are given which determine the moment of inertia of a rotating relativistic fluid star to second order in the angular velocity with no other approximation being made. The equations also determine the moment of inertia of matter located between surfaces of constant density in a rotationally distorted star; for example, the moments of inertia of the crust and core of a rotationally distorted neutron star can be calculated in this way. The method is applied ton=3/2 relativistic polytropes and to neutron star models constructed from the Baym-Bethe-Pethick-Sutherland-Pandharipande equation of state.

Evolution of an Early Proterozoic Continental Margin: The Coronation Geosyncline and Associated Aulacogens of the Northwestern Canadian Shield

Abstract: The Coronation geosyncline developed in the early Proterozoic along the western margin of a continental platform (the Slave Province) of Archaean rocks older than 2300 Ma, and culminated between 1725 and 1855 Ma ago with the emplacement of a pair of batholiths (the Bear Province). The evolution of the geosyncline has a strong family resemblance to Phanerozoic geosynclines believed to delineate ancient continental margins and have been controlled by global plate interactions. Such geosynclines are unknown in Archaean orogenic belts, from which it is inferred that creation of the first large rigid continental platforms marked the end of the Archaean and the beginnings of actualistic plate tectonics. The geosyncline began with deposition of a westward-facing continental shelf, consisting of a lower formation dominated by orthoquartzite, derived from the platform, and an upper cyclic stromatolitic dolomite formation. West of the shelf edge, the dolomite passes abruptly into a much thinner mudstone sequence with dolomite debris-flows, and the orthoquartzite into a thick laminated silt and mudstone sequence with quartzite turbidites. The oldest rocks west of the shelf edge, an area interpreted to have been a continental rise, are pillow basalts and volcanic breccias, extruded above a basement of unknown character. The principal turning point in the evolution of the geosyncline came with the foundering of the continental shelf. It is draped by a thin laminated pyritic black mudstone sequence, overlain by a westward-thickening clastic wedge resulting from intrusion and erosion of the batholiths to the west. The clastic wedge begins with a thick sequence of coarse greywacke turbidites that passes eastward into concretionary mudstone on the platform. The mudstone grades upward into laminated shaly limestone with minor greywacke turbidites, overlain in turn by cross-bedded red lithic sandstone. The supracrustal rocks of the geosyncline have been compressed and tectonically transported toward the platform. Adjacent to the batholithic belt, the continental rise and clastic wedge sequences are penetratively deformed and recrystallized by regional low-pressure metamorphism. To the east, the unmetamorphosed continental shelf and clastic wedge sequences have been flexurally folded and overthrust above a basal detachment surface. East of the thrust zone, relatively thin rocks on the platform are nearly flat-lying except around large anticlinal basement uplifts. Unusual features of the platform are its two aulacogens - long-lived deeply subsiding fault troughs that extend at high angles from the geosyncline far into the interior of the platform. During every phase in the evolution of the geosyncline, the aulacogens received much thicker sedimentary sequences, commonly with the addition of basaltic volcanics, than adjacent parts of the platform. Although equal in thickness to the geosyncline, the aulacogens were never subjected to the batholithic intrusions, regional metamorphism or low-angle overthrusting characteristic of the geosyncline. The Athapuscow aulacogen, in the region of Great Slave Lake, is interpreted as having been an incipient rift, located over a crustal arch, during the continental shelf stage of the geosyncline, but sagged to become a crustal downwarp during the clastic wedge stage, ultimately with sufficient transverse compression to produce broad folds. Finally, the aulacogen became part of a regional transcurrent fault system, along which thick fanglomerates accumulated in local troughs. The batholithic belt consists of two batholiths, eroded to different depths, separated by the north-trending 350 km long Wopmay River fault. The Hepburn batholith, east of the fault, is a composite intrusion of mesozonal granodiorite plutons. The foliated and migmatitic borders of the plutons are normally concordant with wall rock sheaths of sillimanitic paragneiss. Along the eastern margin of the batholith, metamorphosed rocks of the continental rise sequence dip gently to the west beneath the batholithic rocks. Belts of intensely deformed and metamorphosed supracrustal rocks within the batholithic terrain include sequences of pillow basalt, pelites and granite-pebble conglomerate, perhaps the lower part of the continental rise deposited during the initial rifting of the continental margin. The Great Bear batholith, west of the fault, consists of discordant epizonal plutons, mostly adamellite, that intrude broadly folded but regionally unmetamorphosed sequences of welded rhyodacitic ash-flow tuff, trachybasalt and derived sedimentary rocks. The volcanic rocks, intruded by dense dyke swarms radiating from the plutons and by felsite plugs, are interpreted to be comagmatic with the plutons. Mapping is as yet insufficient to establish, speculations aside, the possible relations of the two batholiths to arc-trench systems. Furthermore, the western margin of the batholithic belt, a region of critical importance, is covered by a veneer of younger Proterozoic and Paleozoic sedimentary rocks. Until fossil arc-trench systems are outlined, the contention that the Coronation Geosyncline involved global plate interactions is based on indirect evidence - the analogous evolution of the geosyncline east of the batholithic belt with Phanerozoic geosynclines in which fossil arc-trench systems have been found.

Residual Muscular Soreness as Influenced by Concentric, Eccentric, and Static Contractions

Abstract: Sixty subjects, 53 women and 7 men, were assigned at random to either concentric, eccentric, or static contraction groups. Residual muscular soreness was induced through exhaustive exercises performed on the nondominant arm. Muscular strength and limb volume measurements were taken before exercise, immediately after the bouts, and 24, 48, and 72 hr. later. Soreness was measured during the same time intervals by means of a rating scale. The results showed that eccentric contractions effected greater residual muscular soreness than concentric and static contractions, with the peak occurring after 48 hr. Muscular strength decreased appreciably following eccentric contraction, and remained depressed throughout the duration of the soreness period, while no significant differences in strength were found after concentric and static contractions. Limb volume increased in both exercised and unexercised arms immediately after exercise, regardless of the type of contraction. After 24, 48, and 72 hr., howeve...

Plastic Particle Pollution of the Surface of the Atlantic Ocean: Evidence from a Seabird

Abstract: By sampling with neuston nets, Carpenter and Smith (1972) demonstrated the presence, in 1971, of small particles of plastic on the surface of the Sargasso Sea. The particles had an average concentration of 3500 pieces/km’ and occurred over a distance of 1300 km. The occurrence, reported here, of similar particles in the stomachs of Leach’ s Petrels (Oceanodroma ZeucoAoa) indicates that this form of pollution and its consequences are probably more widespread, both temporally and geographically, than is suggested by the data of Carpenter and Smith. One of seven adult petrels collected in 1962 on Gull Island, off Witless Bay, Newfoundland, had two pieces of plastic in its gizzard. Three of seven adults collected in 1964 on Kent Island, off Grand Manan, New Brunswick, had, respectively, one, one, and four pieces in their gizzards. A fourth bird had a piece of plastic near the junction of its esophagus and proventricuh:s. A Kent Island nestling, found dead in its burrow, had a plastic particle in its gizzard as did one of seven nestlings that survived for up to 2 weeks in captivity. The intestines of all the specimens were examined but no plastic was found. Like other procellariiforms, Leach’ s Petrel often regurgitates some of its stomach contents when handled. Often the regurgitation consists only of stomach oil, but of those regurgitations containing particulate matter none of four from Kent Island or two from Gull Island contained plastic. However, there may be a tendency to retain hard objects (e.g., 9 of the 15 stomachs of adults and nestlings from Kent Island contained structures tentatively identified as polvchaete pharyngeal teeth whereas none of the regurgitations did). As with the plastic described by Carpenter and Smith, most pieces found in the petrel stomachs were white and 0.2-0.5 cm in diameter (Fig. 1). However, many pieces were irregularly shaped and had jagged edges, unlike the pelletshaped pieces with rounded ends described by Carpenter and Smith. It is probable that the type of pollution Carpenter and Smith discovered in 1971 has actually occurred since at least 1962 or 1964. My data also indicate that other areas of the Atlantic, besides the Sargasso Sea, contain pieces of plastic. The petrels could have consumed some of the plastic during their migration, but, while Leach’ s Petrel migrates far south of its North Atlantic breeding areas, it apparently avoids the area of the Sargasso Sea (Palmer 1962). Furthermore, the fact that some of the Kent Island nestlings also contained plastic suggests that their parents were consuming the particles in feeding areas utilized during the breeding season. It is likely that the particles consumed by the petrels were ones which were broadcast over the open ocean and not ones from local concentrations near ships or garbage dumps, since Leach’ s Petrel rarely feeds in littoral waters or follows ships in order to feed on dumped waste material, as is done by related species such as Wilson’ s Petrel ( Oceanites oceanicus) (Peterson 1947:8; pers. observ.). The affinity of Leach’ s Petrels for pelagic areas is shown by the fact that one rarely sees them at sea during the day in the Kent Island region. For example, during a full day in the summer of 1964 on the Old Proprietor Shoal area, about 8 km SE of Kent Island, hundreds of Wilson’ s Petrels were present but not one Leach’ s Petrel was sighted although Wilbur (1969) has estimated that 15,000 pairs breed on Kent Island. But 30 to 40 km S of Kent Island on the Grand Manan Banks, a small number of Leach’ s were observed among the still more numerous Wilson’ s Petrels. Leach’ s Petrels are able to travel 300 km a day while still showing a net gain in weight (Billings 1968). This ability, coupled with the fact that they are often away from their colony for several days, shows that feeding may occur several hundred kilometers from land. Another procellariiform, the Manx Shearwater (Puffinus puffinus), is known to range up to 970 km from its colony while on feeding trips (Lockley 1961:135). The observations presented here enlarge the known scope of the biological effects of these particles as discussed by Carpenter and Smith. From the diversity of its stomach contents (Palmer 1962:233; Rothstein, unpubl. data), Leach’ s Petrel evidently consumes (by independent capturing actions) any ingestible object occurring within a few centimeters of the ocean’ s surface. Before the occurrence of plastic particles, it is probable that nearly all such objects were edible. Thus, natural selection could not have favored petrels which avoided nonedible material. The sudden, widespread appearance of nonedible floating objects such as plastic particles represents an evolutionarily novel event to which the birds do not respond in an adaptive manner. A similar interpretation may explain the consumption of elastic threads by Common Puffins (Fruterculu arctica) reported by Parslow and Jefferies (1972). Of obvious importance is the degree of hazard plastic particles pose to Leach’ s Petrels and to other seabirds. Possibly, the consumption of many particles could result in a blockage or an internal injury, although petrel stomachs often contain hard natural objects such as bits of bone and claw-like objects thought to come from polychaetes. Carpenter and Smith (1972) originally suggested that the plastic may release polychlorinated biphenyls (PCB’ s) to seawater but have since modified this view since the type of plastic involved has PCB’ s only in low concentrations as contaminants (Carpenter et al. 1972). But perhaps even at these low concentrations, consumed particles of plastic could release sufficient amounts of PCB’ s to affect seabirds. The present-day occurrence of plastic particles is

Lead and Strontium Isotopic Studies in the Cascade Mountains: Bearing on Andesite Genesis

Abstract: Note: This paper is dedicated to Aaron and Elizabeth Waters on the occasion of Dr. Waters' retirement. New isotopic analyses of lead are reported for 40 volcanic rocks from the Cascade Mountains of Washington, Oregon, and California. Strontium isotopic compositions were also determined in 33 volcanic rocks from the same area. In addition, lead and strontium isotopic data are given for feldspar and whole-rock samples of prominent varieties of crystalline basement rocks from northern Washington. The Sr87/Sr86 values of the volcanic rocks average 0.7037, with no significant difference between andesite and high-alumina basalt. The ratios exhibit no measurable correlation with strontium concentrations over a range of 200 to 1,500 ppm. Strontium in the Cascade rocks is slightly more radiogenic than that in oceanic ridge basalts, but less radiogenic than in most continental basalt, including the Columbia River basalt. Comparisons with published data for strontium in Pacific Ocean sediments and coastal graywackes in Oregon indicate much higher Sr87/Sr86 values in the sedimentary rocks when compared to the Cascade volcanic rocks, thus ruling out anatectic models involving large sediment contributions. Lead isotopic compositions from the volcanic rocks are variable but tend to be rather constant at a single volcanic center. A noteworthy feature of the lead data are the higher Pb207/Pb204 values (or larger µ values in a model age diagram) for the Cascade volcanic rocks compared to published Pb207/Pb204 values and µ values for Pacific Ocean tholeiitic basalt. The Pb206/Pb204 values from the Cascade volcanic rocks are higher than in oceanic sediments from the northeast Pacific Ocean but are lower than the average ratio for three samples of Oregon coastal sedimentary rocks. There is no demonstrable difference between lead isotopes in high-alumina basalt and andesite at particular volcanos, although the lead data are more variable than the strontium isotope data. Strontium in crystalline basement rocks from northern Washington is substantially more radiogenic than that in the calcic and calc-alkalic volcanic rocks of the Cascade Mountains. The same is true of lead in some, though not all, of the basement rocks. The isotopic data are utilized, along with other trace-element data to test models of andesite genesis. The isotopic compositions of lead and strontium in andesite and high-alumina basalt from the Cascade Mountains are consistent with derivation of the two lava types from a common source, or with derivation of andesite by differentiation of high-alumina basalt magma. The data do not support models in which the Cascade calcic and calc-alkalic magmas were formed by melting of Oregon coastal eugeosynclinal sedimentary rocks, or by anatexis of basement rocks similar to those now exposed near volcanic centers in northern Washington. Various subduction zone melting models are also considered. Mixing models, whereby radiogenic strontium and lead are added to magmas containing lead and strontium with isotopic compositions similar to those in oceanic ridge tholeiite, do not fit the observed data satisfactorily because values of Pb206/Pb204 in Pacific Ocean sediments are too low to account for the Pb206/Pb204 values in the Cascade lavas. Mixtures of eugeosynclinal sedimentary rock and oceanic ridge tholeiite can probably account for the Cascade volcanic rock isotopic data in a general way, but the uniform isotopic composition of strontium in the lavas over a wide range of concentrations is hard to understand in terms of such a model. The same is true for strontium in the oceanic sediment mixing model. The uniform isotopic composition of strontium in the Cascade lavas, irrespective of strontium concentration and geologic setting, argues against contamination of magma with radiogenic strontium during ascent. A similar argument can be made for lead. The best explanation of the isotopic and trace-element data appears to be a multistage model in which orogenic andesite is derived from three or more stages of partial melting of mantle material in which crustal materials play an insignificant role. This model best explains the uniform Sr87/Sr86 values in the lavas over a wide range of strontium concentrations. It can also explain why strontium in lavas extruded at continental margins, such as in the Cascade Mountains and in Japan, has the same isotopic composition as strontium in lavas from the Mariana arc system in the Pacific Ocean. Pb206/Pb204 and Pb208/Pb204 values in Cascade lavas may show a correlation with crustal thickness, but this does not prove that crustal contamination is responsible for the trend. The lead and strontium data exhibit no correlation with the Quartz Diorite Line of Moore.

Tratado descritivo do Brasil em 1587

Abstract: Ao Instituto Historico do Brasil / F. A. de Varnhagen -- Additamento -- pt. 1. Roteiro geral com largas informacoes de toda a costa do Brasil -- pt. 2. Memorial e declaracao das grandezas da Bahia de Todos os Santos, de sua fertilidade e das notaveis partes que tem -- Breves commentarios a precedente obra de Gabriel Soares -- Indice da obra e dos commentarios de Gabriel Soares arranjado pelo commentador.

Consistent Intertemporal Decision Making

Abstract: A plan for an intertemporal consumer (or society) is a (constrained optimum) specification of consumption behaviour from the present to the end of his life (or time horizon). If an individual cannot dictate his future behaviour, he may be inconsistent (Strotz [12]); that is, he may, as time passes, revise his specified future behaviour. Among the many unpleasant features of inconsistent planning is that if an individual behaves myopically (" naively ", cf. Pollak [10]) by continually executing the present portion of his plan, his behaviour, ex post, makes no sense from any point of view. This paper presents alternative ways of looking at intertemporal behaviour, and examines the conditions under which such behaviour is consistent. In Section III, we show that naive intertemporal optimization is consistent only if intertemporal preferences are structured so that the future is functionally separable from the present. In Section lV, we discuss " sophisticated solutions", which have been suggested, [1], [10] and [12], as a planning strategy when the intertemporal preference ordering does not satisfy the necessary condition for consistent naive planning. We prove an existence and uniqueness theorem for sophisticated solutions and find the necessary and sufficient conditions for the "sophisticated " choice functions to be generated by conventional utility maximization.

Tidal Friction in Slowly Rotating Black Holes

Abstract: A stationary distribution of matter outside a Kerr black hole will cause the angular momentum of the black hole to decrease with time provided the distribution is not symmetric about the axis defined by the black hole's angular momentum. The rate of decrease of angular momentum is calculated in the case that (a) the effects of the exterior matter can be treated as a perturbation to the Kerr geometry and (b) the angular momentum of the black hole is small.

Proterozoic Age of the Bambui Group in Brazil

Abstract: Conophyton aff. C. metula Kirichenko is abundant in dolomites of the Paraopeba Formation (Bambui Group) north of Vazante, Minas Gerais, Brazil. That suggests a middle Riphean (Proterozoic) age for the Bambui Group of this region. Such an age, in the range of 950 to 1,350 m.y., and probably closer to the younger number, is consistent with the probable ages of other now known Bambui stromatolites, as well as with the sparse and equivocal radiometric data available. It is older, however, than the Silurian age given on the 1960 geologic map of Brazil and the “upper Eocambrian” age now generally accepted.