Brian S. Creaser

B. Sc. Honours Thesis

Interpretation and modelling of gravity data within the Meguma Terrane, central Nova Scotia

(PDF - 213 Mb)

Gravity methods can be used to identify geological features that exhibit sufficient density contrasts with the surrounding country rock. Collection and reduction of new gravity data in central Nova Scotia, combined with existing regional data, has resulted in a detailed Bouguer gravity map for the study area. This map correlates well with the local geology. Large positive anomalies are associated with the Halifax Formation of the Meguma Group, and large negative anomalies are associated with the South Mountain Batholith (SMB) and the Musquodoboit Batholith (MB). A small negative anomaly situated between the SMB and MB represents the Kinsac Pluton. 2.5D and 3D computer modelling of the intrusive bodies suggest: (1) the SMB and MB join at approximately 4.5- 5 km below the surface, and (2) the smaller Kinsac Pluton is connected to the MB at about 1-1.5 km depth. Modelling of slate belts, using density determinations from this study, indicate: (1) the Kinsac Syncline is arc shaped overlying the intruded granite, (2) the Uniacke Syncline is approximately 2-2.5 km thick, (3) the Rawdon Syncline thickens to the north-east to a maximum depth of 5-6 km, and (4) units of the recently subdivided Halifax Formation, within the study area (Rawdon and Glen Brook Units), can be included in the model of the Rawdon Syncline. The density contrast between them, however, is insufficient to produce recognizable gravity anomalies.

Keywords: detailed, granite, Meguma, reduction, Bouguer, contrast, modelling, subsurface, synclines, 2.5D, 3D
Pages: 84
Supervisor: Patrick Ryall