Sprinkle the gingersnap crumbs onto the bottom and sides of a well-buttered 9-inch springform pan. Chill until ready for filling.
In a large bowl, beat the cream cheese, sugar, flour, cinnamon, nutmeg, cloves, allspice, salt, and eggs until smooth. Add the pumpkin puree and continue to beat until very smooth. Pour the mixture into the chilled springform pan and bake in a preheated 325-degree oven for 1 1/2 hours. Turn off the oven and let the cake stand in the open oven for 30 minutes. Transfer to a wire rack and let cool completely.
Carefully remove the sides of the springform pan. In a chilled bowl, whip the heavy cream and spread it over the top of the cake. Sprinkle the chopped pecans on top of the whipped cream. Transfer the cake to a serving dish and serve.