Structural analysis of the Paint Lake Deformation Zone, Northern Ontario /

The Paint Lake Deformation Zone (PLDZ), located within the Superior Province of Canada, demarcates a major structural and lithological break between the Onaman-Tashota Terrane to the north and the Beardmore-Geraldton Belt to the south. The PLDZ is an east-west trending lineament, approximately 50 km in length and up to 1 km in width, comprised of an early ductile component termed the Paint Lake Shear Zone and a late brittle component known as the Paint Lake Fault. Structures associated with PLDZ development including S-, C- and C'-fabrics, stretching lineations, slickensides, C-C' intersection lineations, Z-folds and kinkbands indicate that simple shear deformation dominated during a NW-SE compressional event. Movement along the PLDZ was in a dextral sense consisting of an early differential motion with southside- down and a later strike-slip motion. Although the locus of the PLDZ may in part be lithologically controlled, mylonitization which accompanied shear zone development is not dependent on the lithological type. Conglomerate, intermediate and mafic volcanic units exhibit similar mesoscopic and microscopic structures where transected by the PLDZ. Field mapping, supported by thin section analysis, defines five strain domains increasing in intensity of deformation from shear zone boundary to centre. A change in the dominant microstructural deformation mechanism from dislocation creep to diffusion creep is observed with increasing strain during mylonitization. C'-fabric development is temporally associated with this change. A decrease in the angular relationship between C- and C'-fabrics is observed upon attaining maximum strain intensity. Strain profiling of the PLDZ demonstrates the presence of an outer primary strain gradient which exhibits a simple profile and an inner secondary strain gradient which exhibits a more complex profile. Regionally metamorphosed lithologies of lower greenschist facies outside the PLDZ were subjected to retrograde metamorphism during deformation within the PLDZ.

Sexual selections in the northern fall field cricket, Gryllus pennsylvanicus: a manipulation of the adult sex ratio

The operational sex ratio has long been considered an important constraint on the structure of mating systems. The effects of an experimentally manipulated sex ratio on mating behavior and selection were investigated in a polygynous species, Gryllus pennsylvanicus, where the potential exists for spatial/temporal fluctuations in sex ratio of field populations. Four different sex ratios (males: females, 5:0, 5:2, 5:5, 5:10) were investigated. Observations were conducted in late summer over two field seasons, from 2400 h , to 1000 h EST. Several male characters thought to be associated with male reproduc.tive success were studied: calling duration, searching distance, weight, fighting behavior, courtship frequency, and mating success. Variance in male mating success was used as the indicator for the opportunity for sexual selection. Total selection was estimated as the univariate regression coefficient between relative fitness and the character of interest, while direct selection was estimated as standardized partial regression coefficients generated from a multiple regression of relative fitness on each character. The opportunity for sexual selection was highest at 5:2 and lowest at 5:10. The frequency of fighting behavior was highest at 5:2 and 5:5. Fighting ability (% wins) was determined to be an important correlate of male body weight. Direct selection for increased male body weight was detected at 5:2, while total selection for body weight was seen at 5:5. Selection on male body weight was not detected at 5: 10. Calling duration decreased as sex ratio became more female-biased. Total and direct selection were detected for increased calling at 5:2, only total selection for calling was seen at 5:5, whereas direct selection against calling was detected at 5: 10. Searching distance also decreased as sex ratio became more female-biased, however no form of selection was detected for searching at any of the sex ratios. Data are discussed in terms of sexual selection on male reproductive tactics, the mating system and maintenance of genetic variation in male reproductive behavior.

Colum C. Chapman, Chicago, Illinois

Cabinet card photographic portrait of Colum C. Chapman in his National Guard uniform, Chicago, Illinois, ca. 1890.

Frank M. Chapman, Jr. son of Frank M. and Wilhelmina Chapman, Chicago, Illinois, ca. 1891.

Studio portrait of Frank M. Chapman, Jr. son of Frank M. and Wilhelmina Chapman, Chicago, Illinois, ca. 1891.

Frank C. Chapman, Chicago, Illinois, ca. 1890

Studio portrait of Frank C. Chapman, Chicago, Illinois, ca. 1890.

Label, "Clarke & Chapman, Packers and Jobbers of Green Apples, Macomb, Illinois

Label on card stock for "Clarke & Chapman, Packers and Jobbers of Green Apples, Macomb, Illinois, 1870-1878"

Wilhelmina Zillen Chapman, Chicago, Illinois, 1892

Cabinet card portrait of Wilhelmina Zillen Chapman, mother of Grant Chapman and grandmother of Joyce Chapman, taken by G. D. Morse, Chicago, Illinois, July, 1892.

Charles C. and Lizzie Chapman with daughter Ethel, Chicago, Illinois

Charles C. Chapman and his wife, Lizzie Pearson Chapman, with baby daughter Ethel in a hammock, Chicago, Illinois, ca. 1885.

Mrs. Heppenstall, a member of the Chapman family, Abington, Illinois

Cabinet card photographic portrait of Nancy Wallace Pearson Heppenstall [1834-1916], taken in the studio of William Johnston, Abington, Illinois. She was the mother of Lizzie Pearson Chapman, wife of Charles Clarke Chapman.

E. Joe Clarke, Monmouth, Illinois

Cabinet card photographic portrait of E. Joe Clarke, taken in the Root studio, Monmouth, Illinois.

Unidentified member of the Chapman family, Hattoon, Illinois

Unidentified studio portrait of a member of the Chapman family, taken in the Teitzell Studio, Hattoon, Illinois.

Residence, Sterling, Illinois

Residence [written over photograph: "Home 1916-1919"], possibly Sterling, Illinois, ca. 1919.

Central Park, Sterling, Illinois

Written on front: "Central Park, Sterling, Illinois, 24729." Written on back: "My playground 1911-13 and 1916-19."

Samuel James Chapman, Illinois, ca. 1880

Portrait of a young Samuel James Chapman, taken in Illinois, ca. 1880.