Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Critelli, S. Articles by Busby, C. J. Search for Related Content GeoRef GeoRef Citation

Tectonic history of a Jurassic backarc-basin sequence (the Gran Cañon Formation, Cedros Island, Mexico), based on compositional modes of tuffaceous deposits

Salvatore Critelli^*,1, Kathleen M. Marsaglia^,2 and Cathy J. Busby^,3

¹ Dipartimento di Scienze della Terra, Università degli Studi della Calabria, 87036 Arcavacata di Rende (CS), Italy
² Department of Geological Sciences, California State University, Northridge, California 91330-8266, USA
³ Department of Geological Sciences, University of California, Santa Barbara, California 93106, USA

The Jurassic Gran Cañon Formation (Cedros Island, Baja California, Mexico) constitutes an unusually well preserved and exposed example of ancient backarc-basin fill. Petrofacies analysis conducted on tuffaceous sandstone and tuff samples from this formation complement and reinforce prior lithofacies interpretations, but with some modification. When temporal and spatial trends in petrographic data (detrital modes) are analyzed and compared to models based on data collected from Deep Sea Drilling Project and Ocean Drilling Program cores, the trends indicate a second, heretofore unrecognized, phase of backarc rifting. Basalt lavas interstratified with dacitic pyroclastic rocks of the primary volcanic lithofacies, previously interpreted to record the eruption of differentiated magmas at the climax of growth of the Gran Cañon island arc, are now as a result of this study considered to be the product of arc extension and rifting.

Our method of modal analysis uniquely combines the quantification of textural attributes of pyroclastic and epiclastic debris that reflect eruption style and magma composition, as well as the effects of reworking and mixing in marine settings. This study demonstrates that detailed petrographic analysis is useful in the interpretation of ancient volcaniclastic deposits suspected of having formed in backarc-basin settings.

Key Words: backarc basins • Baja California • Jurassic • magmatic arcs • Mexico • provenance • sandstone petrology • volcanology

This article has been cited by other articles:

				M. Grove, G.E. Bebout, C.E. Jacobson, A.P. Barth, D.L. Kimbrough, R.L. King, H. Zou, O.M. Lovera, B.J. Mahoney, and G.E. Gehrels The Catalina Schist: Evidence for middle Cretaceous subduction erosion of southwestern North America Geological Society of America Special Papers, January 1, 2008; 436(0): 335 - 361. [Abstract] [Full Text] [PDF]