Preheat oven to 180 degrees C. In a medium bowl mix together the crushed biscuits, pecans and butter. Press into the bottom and about 3cm up the sides of a 20cm springform pan. Bake crust 10 minutes in the preheated oven. Set aside to cool.
In a medium bowl mix together the cream cheese, 1/2 cup sugar and vanilla just until smooth. Mix in eggs one at a time, blending well after each. Set aside 1 cup of the mixture. Blend 1/4 cup sugar, pumpkin, cinnamon and nutmeg into the remaining mixture.
Spread the pumpkin flavoured batter into the crust and drop the plain batter by spoonfuls onto the top. Swirl with a knife to create a marbled effect.
Bake 55 minutes in the preheated oven or until filling is set. Run a knife around the edge of the pan. Allow to cool before removing pan rim. Chill for at least 4 hours before serving.