The Bass Islands Formation in its Type Region

Author Institution: Southwest Minnesota State College, Marshall, MinnesotaThe Upper Silurian Bass Islands Formation has as its type region the Bass Islands, of Ottawa County, Ohio. Originally divided into the Greenfield, Tymochtee, Put-in-Bay, and Raisin River subunits, it has been classed as a series, group, and formation by different workers, and has been redefined, restricted, and even eliminated in the subsurface by others. The Bass Islands is here considered to be a formation, divisible, in the type region, into the four members listed above. The formation, which consists entirely of hypersaline facies, disconformably overlies the marine Lockport ("Guelph") Dolomite and is separated from the overlying Amherstburg Dolomite by the Tippecanoe-Kaskaskia unconformity. The Greenfield Member consists of about 110 feet of dolomite lacking in argillaceous matter. It is equivalent to the A1 unit of the Salina of subsurface terminology, and a widespread disconformity at its top corresponds to the "Newburg" zone of the subsurface. The Tymochtee Member comprises about 560 feet of dolomite, anhydrite, gypsum, and shale which correspond to the A2 and other lettered subdivisions of the Salina. Disconformably overlying the Tymochtee are about 80 feet of dolomite forming the Put-in-Bay and Raisin River members, which can be differentiated (by degree of brecciation) only in the Lake Erie islands. Brecciated units characterize the Put-in-Bay, and breccias locally occupy channels cut into the upper part of the Tymochtee. The Raisin River is characterized by more limited brecciation and by pseudobreccias. The paleogeographic setting and association with penesaline facies suggest that most carbonates of the Bass Islands Formation have been dolomitized by seepage refluxion prior to final lithification

Anomalous Drainage Pattern and Crustal Tilting in Ottawa County and Vicinity, Ohio

Author Institution: Department of Geology, Earlham College, Richmond, IndianaOttawa County, Ohio, is situated near the western end of Lake Erie on a flat glaciallake plain that is interrupted by bedrock highs only at the western and eastern ends of the county. The drainage pattern on the lake plain is anomalous in that the courses of the major streams do not trend directly down the present slope normal to its strike. The entire region has apparently experienced tilting down to the north about an axis trending approximately east-west, producing an increased gradient to the north and resulting in considerable stream piracy. The tilting involved differential movement on the order of 2.8 feet per mile and is believed to be related to isostatic adjustment during and following the last stages of Pleistocene glaciation

Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture

The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation)

STR-846: METHODS OF COMPARING EXTREME LOAD EFFECTS BASED ON WEIGH-IN-MOTION DATA

The estimation of extreme load effects caused by vehicles is of critical importance in the evaluation and design of bridge structures. Two methods for estimating extreme load effects over the service life of bridges are commonly cited in literature: (1) the use of a fitted probability distribution based on statistical data to extrapolate the extreme load effects on a probability plot, or (2) the application of Monte Carlo simulation to generate representative truck data over a bridge’s lifespan such that maximum load effect values can then be determined directly. In this paper, results obtained using the two aforementioned methods are presented including their advantages and disadvantages in the context of the analysis of rural bridges in Saskatchewan. For this purpose, estimated load effects are based on truck data recorded over a period of one year at several weigh-in-motion (WIM) stations located on Saskatchewan highways. The conducted analyses are based on a typical bridge type common to rural Saskatchewan. It was found that the Monte Carlo simulation approach resulted in more reliable extreme load effect estimations, along with providing other information that is of value in the development of new truck loading models

STR-815: FEASIBILITY OF USING UNBONDED REINFORCEMENT IN CONCRETE BLOCK WALLS

An experimental program is underway at the University of Saskatchewan to investigate the performance of concrete masonry block walls reinforced with non-prestressed, unbonded reinforcement that are subjected to out-of-plane lateral loads. By eliminating the need for grouting, this construction method may lead to substantially lower wall weights, as well reduced construction times, cost, and workplace injuries. At the same time, the presence of reinforcement will increase the flexural strength of the walls, significantly increasing the allowable vertical spans of such walls as compared to those of comparable unreinforced walls. Unreinforced walls, as well as conventionally reinforced and partially grouted walls, were included in the experimental program to serve as control specimens against which the performance of the walls with unbonded, ungrouted reinforcement could be compared. Although the experimental program is ongoing, preliminary results described herein comparing the unbonded reinforced walls to unreinforced companion specimens suggest that this construction method is a promising alternative to more conventional systems

The Null Decomposition of Conformal Algebras

We analyze the decomposition of the enveloping algebra of the conformal algebra in arbitrary dimension with respect to the mass-squared operator. It emerges that the subalgebra that commutes with the mass-squared is generated by its Poincare subalgebra together with a vector operator. The special cases of the conformal algebras of two and three dimensions are described in detail, including the construction of their Casimir operators.Comment: 31 page

Twistors, special relativity, conformal symmetry and minimal coupling - a review

An approach to special relativistic dynamics using the language of spinors and twistors is presented. Exploiting the natural conformally invariant symplectic structure of the twistor space, a model is constructed which describes a relativistic massive, spinning and charged particle, minimally coupled to an external electro-magnetic field. On the two-twistor phase space the relativistic Hamiltonian dynamics is generated by a Poincare scalar function obtained from the classical limit (appropriately defined by us) of the second order, to an external electro-magnetic field minimally coupled, Dirac operator. In the so defined relativistic classical limit there are no Grassman variables. Besides, the arising equation that describes dynamics of the relativistic spin differs significantly from the so called Thomas Bergman Michel Telegdi equation.Comment: 39 pages, no figures, few erronous statements (not affecting anything else in the papper) on page 23 delete

Trajectory Mapping and Applications to Data from the Upper Atmosphere Research Satellite

The problem of creating synoptic maps from asynoptically gathered trace gas data has prompted the development of a number of schemes. Most notable among these schemes are the Kalman filter, the Salby-Fourier technique, and constituent reconstruction. This paper explores a new technique called trajectory mapping. Trajectory mapping creates synoptic maps from asynoptically gathered data by advecting measurements backward or forward in time using analyzed wind fields. A significant portion of this work is devoted to an analysis of errors in synoptic trajectory maps associated with the calculation of individual parcel trajectories. In particular, we have considered (1) calculational errors; (2) uncertainties in the values and locations of constituent measurements, (3) errors incurred by neglecting diabatic effects, and (4) sensitivity to differences in wind field analyses. These studies reveal that the global fields derived from the advection of large numbers of measurements are relatively insensitive to the errors in the individual trajectories. The trajectory mapping technique has been successfully applied to a variety of problems. In this paper, the following two applications demonstrate the usefulness of the technique: an analysis of dynamical wave-breaking events and an examination of Upper Atmosphere Research Satellite data accuracy

A Lagrangian View of Stratospheric Trace Gas Distributions

As a result of photochemistry, some relationship between the stratospheric age-of-air and the amount of tracer contained within an air sample is expected. The existence of such a relationship allows inferences about transport history to be made from observations of chemical tracers. This paper lays down the conceptual foundations for the relationship between age and tracer amount, developed within a Lagrangian framework. In general, the photochemical loss depends not only on the age of the parcel but also on its path. We show that under the "average path approximation" that the path variations are less important than parcel age. The average path approximation then allows us to develop a formal relationship between the age spectrum and the tracer spectrum. Using the relation between the tracer and age spectra, tracer-tracer correlations can be interpreted as resulting from mixing which connects parts of the single path photochemistry curve, which is formed purely from the action of photochemistry on an irreducible parcel. This geometric interpretation of mixing gives rise to constraints on trace gas correlations, and explains why some observations are do not fall on rapid mixing curves. This effect is seen in the ATMOS observations