The cross section below represents large boulders made of granite, gneiss, and quartzite that are found lying on limestone bedrock near Oswego New.

If no overturning of bedrock has occurred, which statement correctly explains the source of the boulders?
A)The limestone was changed by contact metamorphism caused by a lava flow

B)The limestone bedrock formed under conditions of high heat and pressure

C) Older igneous and metamorphic bedrock that once covered the limestone eroded away, forming the boulders

D) The boulders were transported and deposited on the limestone bedrock by a glacier

  D)  The boulders were transported and deposited on the limestone bedrock by a glacier

Explanation:

Limestone is a soft sedimentary rock, so it is unlikely that any heat or pressure were ever applied to the bedrock in this area, or to anything overlaying that bedrock.

Much of New York state was deeply affected by glaciation, which moved a terrific amount of material. It is much more likely that the boulders were transported by glaciers to their current locations.

the answer to you question is   jet streams

glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.