Trip Leaders:     Jim Reynolds, Brevard College, jim@magstrat.com (Phone: 828-230-8405)
                                                    and
                        Dottie Stout, Cypress College, gaea@deltanet.com

Travel Arrangements: SumajKay Travel Agency, Salta, Argentina, sumajkay@arnet.com.ar
            (Phone: 011-54-387-431-6101)
 

    The main purpose of this trip is to introduce the participants to the wide variety of structural styles exhibited in the Andes of northwestern Argentina. The region is often considered to be a modern analog of the Cretaceous-Eocene Laramide Orogeny in the western United States.
    Numerous tectonic provinces developed in response to Nazca Plate subduction beneath the South American continent. Variation in structural style is not only evident between the high mountains and foreland regions but also changes with latitude due to changes in dip of the subducting slab. North of 24º S, the Nazca Plate subducts "normally" at about a 30º angle. The area between 28º S and 36º 15' S is referred to as the "flat" subduction region. The subducting slab extends far eastward at a subhorizontal angle just beneath the continental lithosphere. No Quaternary volcanoes are present in the Andes at these latitudes. Between the "flat" and "normal" areas is the Transition Zone (24º S-28º S) in which aspects of the structural development derived from laterally adjacent provinces are present.
    In addition to the tectonic stories the region has to tell, it is also a treasure trove of Mesozoic and Cenozoic vertebrate fossils. Dinosaur bones from late Triassic to late Cretaceous age continue to be discovered. These include the oldest known dinosaur Eoraptor lunensis. (There might be a new, slightly older dinosaur that was found in Africa last year.)
    Charles Darwin visited the southwestern part of the area while on an excursion from H.M.S. Beagle. After leaving the ship at Valparaïso, Chile, he traversed the Andes on horseback to visit Mendoza province. He followed a different route over the mountains on his return trip to the ship. This same pass holds an important place in Argentine and Chilean history. In a bold move,  San Martín, the liberator of Argentina, Chile, and Peru led his troops across the Andes in January 1817. The "Army of the Andes" joined with Chilean forces to defeat the Spanish at Chacabuco in a decisive battle for independence.

    Our travel arrangements are made through the gargantuan efforts of SumajKay Travel Agency in Salta, Argentina. They assure us that we will arrive as their clients but leave as their friends. The itinerary is now pretty well set. Minor changes will undoubtedly occur but this is the general plan: We will travel through Argentina in El Viento Blanco--"the White Wind"--SumajKay's vista cruiser (see photos on the SumajKay website).
 

Itinerary:
July 24 - The group will assemble at the LAPA gate at Hartsfield Airport, Atlanta prior to our flight from Atlanta to Buenos Aires, Argentina on LAPA airlines. Dottie will meet the group in Atlanta and Jim will meet them at the airport in Buenos Aires.

July 25- Arrival at Ezeiza Airport, Buenos Aires in the morning. Transfer to Jorge Newberry airport by bus where we will check our bags. We'll then take taxis to a nearby restaurant for lunch and return for our afternoon flight to Salta. SumajKay will meet us at the airport and takes to our hotel on the Plaza Central of the city. Afternoon in Salta.  We will have dinner and a show at la Peña Balderrama, Salta's oldest and best known establishment of this type. HOTEL SALTA, (b)

July 26 - This day's trip will take us through the petroleum-producing Neogene Santa Bárbara System fold-thrust belt, located in the eastern part of the Transition Zone between the normal and flat subduction segments of the Nazca Plate.  We will visit the Parque Nacional de Reyes which is a lush subtropical forest with tremendous diversity of birds and  mammals. Lunch will be in the park and dinner will be at Rancho "El Fogon" on the return trip to Salta. HOTEL SALTA, (b)

July 27 - This is a trip everyone must do when visiting Salta: the Tren a las Nubes--the "Train to the Clouds". This is a railroad ride on the Puna--the southern extension of the Altiplano. The trip starts in Salta and climbs through the spectacular vistas of the Quebrada del Toro (Bull Ravine) to the high Puna plateau. Typical basin elevations are 3600 m. El Viento Blanco will meet us in San Antonio de los Cobres and we will head northward on Ruta 40 across the world's highest salt flats (Salinas Grandes). We'll descend through the picturesque Cuesta del Lipan to the beautiful Purmamarca Indian village and handicraft market before heading to Uquía where we will spend the night. HOSTAL DE UQUIA--Uquía (b).

July 28 - This will be a full day of exploration of the Quebrada de Humahuaca in the normal subduction region of Jujuy Province, One highlight will be a visit to the reconstructed pre-Inca ruins of Tilcara.  Spectacular environmental geology problems caused by active alluvial fan deposition abound in the area. We'll return to Uquía for the night. Dinner will be accompanied by a native group playing Andean melodies on traditional instruments. HOSTAL DE UQUIA--Uquía (b).

July 29- Return to Salta - remainder of day at leisure with an optional city tour, a walk through the Quebrada San Lorenzo, and shopping at Mercado Artesanal.  Dinner will be at the Solar del Convento, one of Salta's finest restaurants. HOTEL SALTA (b)

July 30 - We will say good-bye to Salta and head through the southern Cordillera Oriental, in the Transition Zone, over the Cuesta del Obispo. We will then pass through the Parque Nacional de los Cardones (a saguaro cactus forest) to the village of Cachi. From here we will begin to descend the Valles Calchaquíes, spending the night in Molinos--a quaint village in a scenic spot. HOTEL PROVINCIAL--Molinos, (b)

July 31 - In the morning we will continue our descent of the Valles Calchaquíes to Cafayate, stopping to walk through the Neogene strata exposed along the river near Angastaco. During the afternoon we will examine some of the geology of the nearby Quebrada de las Conchas where strata deposited in a cannibalized Neogene foreland basin overlie Cretaceous rift basin strata.  We will examine the evolution of depositional environments as orogenic development progressed. HOTEL ASTURIAS (b)--Cafayate

August 1 - We'll get up early to finish our exploration of the Quebrada de las Conchas and return to Cafayate for lunch. After lunch we'll visit one of the region's fine wineries. We will see the Quilmes ruins and the spectacular geology of the Santa María Valley in the Eastern Cordillera and Sierras Pampeanas--one of the most beautiful areas of northern Argentina. Thick deposits of deformed Neogene strata record the uplift history of the Sierras Pampeanas on the northern edge of the flat subduction area and southern Transition Zone. HOTEL DE TURISMO--Santa María (b,d)

August 2 - On this day we will leave the Transition Zone and enter the flat subduction area in the Laramide-style uplifts of the Sierras Pampeanas in Catamarca and La Ríoja provinces.  We will stop to view exposures of the Precambrian (Grenville) basement metamorphic complex, AUTOMOVIL CLUB DE ARGENTINA HOTEL--Chilecito (b,d)

August 3 -  We will visit the Río Amarillo at the base of the 20,000' high Sierra de Famatina, viewing a porphyry copper deposit above us at 17,000' and environmental problems caused by gold mining.  In the afternoon we will cross the Sierra de Sañogasta, examining Ordovician basement exposures that may be related to eastern North America.  Night in Villa Unión at HOTEL DAYTON.(b,d)

August 4 - This will be another full day of exploration of the flat subduction area with a visit to Valle de La Luna National Park--the area in which the oldest known dinosaurs (228 Ma) were discovered. We will also get an overview of the tectonic history of the flat subduction segment while looking at Neogene exposures in the Campo de Talampaya in the western Sierras Pampeanas.  We will again stay at Villa Unión.  HOTEL DAYTON, (b,d)

August 5 -  We traverse the Precordillera fold-thrust belt along the antecedent Río Jáchal which exposes Paleozoic strata with a Taconic affinity and dismembered Ordovician ophiolite at the base. We will stay in Pismanta, noted for its hot spring bath and striking view of the Cordillera Frontal, HOTEL TERMAS PISMANTAS--Pismanta (b,d)

August 6 - An unhurried day in Pismanta. Activities could include relaxing in the geothermal baths, a hike through the scenic Rodeo section or a bus trip into the Frontal Cordillera (weather permitting). HOTEL TERMAS PISMANTAS (b,d)

August 7 - We will head south between the Frontal Cordillera and the Precordillera along the Iglesia piggy-back basin on our way to Calingasta. The trip has imposing views of the high Andes including Cerro Aconcagua, the highest peak in the western hemisphere.  From Calingasta we will head eastward in the afternoon on an unforgettable trip through the antecedent gorge of the Río San Juan.  The city of San Juan is the locus for seismic activity along the boundary between the Precordillera and the Sierras Pampeanas. HOTEL NOGARO--San Juan, dinner at the Club Sírio-Libanes, (b,d)

August 8 - On this day we depart for Mendoza travelling between the southern Sierras Pampeanas and Precordillera. Winery tour in the afternoon HOTEL MENDOZA (b).

August 9 - A trip through the scenic valley at the eastern base of the Cordillera Frontal to the town of Uspallata. Weather permitting, we will ascend the highway to the Puente del Inca natural bridge and Los Penitenes ski area HOTEL MENDOZA (b).

August 10 - Morning flight from Mendoza to Buenos Aires with sightseeing in Buenos Aires. We will have dinner at "La Ventana", one of the famous tango clubs in a well-known tango neighborhood. HOTEL BRISTOL (b,d)

August 11 Day in Buenos Aires with city tour. Shopping and individual sightseeing  HOTEL BRISTOL

August 12 - Morning flight to the Cataratas de Iguazú. We will spend the afternoon visitingthe Argentine side these magnificent waterfalls--one of South America's natural wonders. Night at Iguazú. HOTEL LIBERTADOR (b, d)

August 13 - We will arise early. In the morning we will visit the Brazilian side of the falls. This is one of the rare places in the world where visitors are free cross an international border without the hassle of customs. Just don't stray too far! After lunch a bus will take us to the airport and we will return to Buenos Aires. Another bus will take us directly from Jorge Newberry Airport to Ezeiza Airport. Our flight to Atlanta leaves in the early evening so dinner will be in flight.

August 14 - Early morning arrival in Atlanta.  Continue to home airport.
 

Flight Arrangements
We have reservations on the following LAPA flights:

Atlanta to Buenos Aires             24 July         LAPA 3901     Depart 2200      Arrive 0800 the following morning
Buenos Aires to Salta                25 July         LAPA 3172     Depart 1640      Arrive 1840
Mendoza to Buenos Aires         10 August     LAPA 3192     Depart 0850      Arrive 1120
Buenos Aires to Iguazú              12 August     LAPA 3292     Depart 1252     Arrive  1432
Iguazú to Buenos Aires              13 August     LAPA 3291     Depart 1505     Arrive  1715
Buenos Aires to Atlanta             13 August     LAPA 3900     Depart 1900     Arrive  0640 the following morning
 

Cost:  $3900 for GSA members, $4,000 for non-GSA members.  Does not include international airfare. Airfare price for the 6 flights involved is $1152, of which $511 is for the international flights.

For more details, contact Edna Collis at ecollis@geosociety.org or phone 1-800-472-1988.