麻豆传媒

B.Sc. (Honours) Thesis

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Point Pleasant Park has been a landmark of the city of Halifax for over 200 years. Originally built as a military base in 1796, Point Pleasant Park was leased to the people of Halifax in 1873 by Queen Victoria for a shilling a year for 999 years. The Park was recommissioned during the two world wars and since has been a municipal park for all of the residents in Halifax to enjoy. The devastation brought about by Hurricane Juan provided an opportunity to study the bedrock geology within Point Pleasant Park. The bedrock geology of the Halifax peninsula was originally assigned to the Cunard member of the Halifax Formation. After careful observation, the bedrock geology within the park has been assigned to a different unit, informally named the Bluestone member after an old quarry on the western side of the North West Arm. The Bluestone member is an interlayered metasiltstone-slate turbidite unit lying gradationally on top of the Cunard member. Two subdivisions of the Bluestone member have been identified within the Park. Unit A is interlayered metasiltstone and slate containing abundant calcareous concretions. This unit starts at the southern tip of the park and continues north until the last occurrence of calcareous concretions at Cable Rock. Unit B is similar in lithology to unit A but has no observed concretions. The lithology of the park has been folded into a large-west plunging syncline with the fold axis located at the northern edge of the park. Two different metamorphic events have affected the rocks within the park. Regional metamorphism occurred along with the folding during the Acadian Orogeny (ca. 390 Ma) and has metamorphosed the Bluestone member to greenschist (chlorite zone) facies. Contact metamorphism caused by the intrusion of the South Mountain Batholith (ca. 380 Ma) overprinted the regional metamorphism producing cordierite, which has weathered out to give the rocks their characteristic Aspotted@ appearance.