Italian cross section (recent)

Western U.S. cross section (370 Ma)

87Sr/86Sr = 0.706

hingeline

Burchfiel & Royden(1991)

Royden & Burchfiel (1991)Lund (2008)Lund (2008) BurchfielRoydenAntler_Overheads.ppt

Draw two cross sections on theother side of this page, oneacross the region of modernItaly, the other across westernU.S. at ~370 Ma (during theAntler orogeny).List some of the majorsimilarities and differences. Onthe western U.S. cross section,show the topographic divide.The following passage is inBurchfiel and Royden:

Explain briefly why each of these is important, andinclude these ideas in your cross section.

Following Burchfiel nd Royden, sketch the position of the Klamath-Sierran volcanic arc,Havallah Basin, Antler allochthon and Antler foredeep at an initial stage of development, andat a late stage of development. Show where extension is occurring, sediment transport(arrows going from source to sink), and the topographic divide. (Basin and Range extension has widened the area between the hingeline and the rift margin. Draw your sketch on the map shown, which is of the current locations.)

Antler Orogeny (again)

hing

e-lin

e

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Med

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, with

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ey a

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the

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the

north

.