Crustal thickness variation in south-central Alaska

Publication Type  Journal Article
Year of Publication  2006
Authors  Veenstra, E.; Christensen, D. H.; Abers, G. A.; Ferris, A.
Journal Title  Geology
Volume  34
Issue  9
Pages  781-784
Journal Date  Sep
ISBN Number  0091-7613
Accession Number  ISI:000240504300020
Key Words  alaska range; crust; passcal; mohorovicic discontinuity; isostasy; teleseismic signals; angle reflection data; yukon-tanana terrane; east-central alaska; subduction zone; receiver functions; transect; beneath; tectonics; plateau; margin

Crustal thicknesses have been determined by receiver function analysis of broadband teleseismic waveforms recorded during the Broadband Experiment Across the Alaska Range (BEAAR). Typical crust beneath the northern lowlands is 26 km thick, while beneath the mountains it is 35-45 km thick. The transition from thick to thin crust coincides with the location of the Hines Creek fault, a major tectonostratigraphic boundary. Crustal thicknesses determined by receiver functions agree with those predicted from topography assuming Airy type isostasy, suggesting that the Alaska Range is compensated by its crustal root. North of the range, however, the crust is systematically thinner than predicted by simple Airy isostasy. A crustal density contrast of 4.6% across the Hines Creek fault, 2700 kg m(-3) to the north and 2830 kg m(-3) to the south, explains the observed difference between the crustal thicknesses predicted by simple Airy isostasy, and the crustal thicknesses determined by receiver function analysis.


084AQTimes Cited:4Cited References Count:34

URL  <Go to ISI>://000240504300020
DOI  Doi 10.1130/G22615.1