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Mesozoic to Cenozoic sedimentation, tectonics, and metallogeny of Sonora, Mexico

September 4, 2019

We will embark on a five-day journey through northern, western, and central
Sonora, in which we will see excellent examples of mostly Mesozoic to Cenozoic tectonics,
sedimentation, and metallogeny. On Day 1, we will visit the porphyry copper
deposit at Ajo, Arizona, and several Pleistocene cinder cones and maar craters in
the Pinacate Biosphere Reserve. On Day 2, we will see L- and L-S tectonites at the
type locality of the Mojave-Sonora megashear in Sierra Los Tanques, Noche Buena
orogenic gold deposit, Ediacaran Gamuza beds in Caborca, and have an overview
of the Carnero detachment fault on the south side of Sierra La Gloria. Day 3 will
explore faults and related sedimentary and volcanic rocks associated with the late
Miocene oblique opening of the Gulf of California rift and visit outcrops that record
late Miocene timing constraints for flooding of the Gulf of California seaway, including
several localities on southern Isla Tiburón accessible only by boat. Day 4 will
visit exposures of Permian sedimentary to Paleogene igneous rocks in Hermosillo
(Cerro La Campana); Puerto del Sol detachment fault zone; Aconchi batholith and a
hot spring localized on a Basin and Range normal fault; Santa Elena low-sulfidation
epithermal gold mine; and the Upper Jurassic Cucurpe Formation. On Day 5, we
will visit several exposures of different crustal levels of the Magdalena-Madera metamorphic
core complex, including the spectacular stretched pebble conglomerates in
Arroyo Amolares.