Full title: FT26CD02. Espíritu Santo and La Partida Islands, BCS, Mexico: Links between the Comondú and Sierra Madre Occidental Volcanic Fields?
Leader(s): José Jorge Aranda-Gómez, José Antonio Pérez-Venzor. Pablo Dávila-Harris, Mariano Cerca
Endorser(s): GSA Structural Geology and Tectonics Division, Sociedad Geológica Mexicana, A.C. (SGM)
CEUs: 1.6
Date(s): Sun–Tue., 19–21 Apr.
Location: La Paz, Baja California Sur, Mexico (trips ends in Loreto)
Start Time: 5 p.m.(first day)
End Time: 5 p.m. (last day)
Description: This 2-day geological excursion offers an opportunity to see the southernmost outcrops of the Comondú Group near La Paz. Day 1 will be a boat excursion from La Paz to Punta Coyote and Espíritu Santo and La Partida islands. We will visit the Punta Coyote volcanic complex, where chaotic andesitic breccias and gently-inclined ignimbrites and epiclastic-volcanic units are visible in coastal exposures. Folded, tilted, and faulted rocks of the Lower Comondú Group will be seen and discussed. After crossing the channel, we will navigate around the islands, providing iconic views of ignimbritic and epiclastic-volcanic successions, paleochannels parallel to the present-day drainage system, and NW-trending normal faults related to the Gulf’s opening. These exposures will allow participants to interpret the lithostratigraphic succession and structural relationships critical for understanding the evolution of volcanism and transition to a rift margin. During Day 2, we will travel by road from La Paz to Loreto, stopping to study deformed rocks of the Lower Comondú Group south of San Juan de la Costa. We will visit the type locality of the Agua de Yepis structural complex. The discussion will be centered in the role played by a voluminous volcanic debris avalanche in the deformation of unconsolidated and wet tuffs and epiclastic-volcanic sediments. Evidence of soft sediment deformation, complex folding, sediment mixing and mingling, and presence of exotic blocks will be shown. On the drive north, we will stop to discuss a panoramic view of the Comondú Group and other volcanic rocks exposed south of Loreto.
Considerations: Moderate. Boat access only; no walking required, but participants may get wet during crossing. Navigation might become a bit rough if wind is blowing in the channel that separates the islands from the mainland. The official field trip will begin on the morning of Mon. 20 Apr. Participants will arrive and stay at Araiza Palmira hotel on the evening of Sun. 19 Apr.
By purchasing this item, you are buying a seat for an in-person geological field trip
Field Trips offer Continuing Education Units (CEUs). One CEU equals 10 hours of participation in an organized continuing education experience under responsible sponsorship, capable direction, and qualified instruction.
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For additional information, please contact fieldtrip@geosociety.
Product Code: FT26CD02
Product Category: FTRIP