Continental drainage in North America during the Phanerozoic from Nd isotopes

Neodymium (Nd) isotopic data show consistent patterns in the sources of sed imentary rocks in North America at a continental scale. Between 600 and 450 million years ago (Ma), ancient continental shield sources dominated. Arou nd 450 Ma, detritus from the Caledonian-Appalachian mountains overwhelmed s ediment from all older sources, and is documented over Large areas of the s outhern, western, and northern margins of North America. This material cont inued to dominate the sediment supply until about 150 Ma, probably due to c annibalistic recycling of sedimentary rocks formed earlier. Around 150 Ma, the rising western Cordillera delivered new and different detritus to the s edimentary system.