Barcelona Field Studies Centre

Tectonic Activity and Hazards Field Studies in the Garrotxa Volcanic Park

The Garrotxa Volcanic Zone is situated 100 kilometres to the north of Barcelona, an approximate road journey of two hours. It contains some of the most interesting volcanic landscape in Europe. There are thirty Strombolian volcanic cones, a few explosive phreatomagmatic craters, other alternating Strombolian/explosive volcanoes and over twenty very unusually constructed basaltic lava flows. In addition, the area's moist Mediterranean mountain climate has contributed to lush vegetation and a spectacular landscape.Tossols in fageda d'en Jordą, Garrotxa Volcanic Park

Moves to give the volcanic zone legal status go back as far as 1917 but it was not until 1975 that a serious conservation campaign won widespread support, culminating in protective legislation in 1982. A sharp rise in urbanisation and industrial development in the area had begun to affect the traditional rustic landscape. Volcanic craters were being used as civic refuse disposal sites and a particularly grave threat to the survival of some of the most interesting volcanoes was posed by cinder quarries taking material for use in building block manufacture.

Volcanism is of a basic type, involving basanitic and basaltic lava. The last dated eruption occurred 11,500 years ago, thus though volcanic activity has ceased, it cannot be considered to be finally extinct. The volcanic eruptions varied greatly in intensity owing to the characteristics of the substratum crossed by the vent and especially because the magma encountered layers of water-saturated materials.Chew Valley School, November 2001: Croscat Volcano

The thirty or so volcanic cones are in a very good state of natural conservation, considering their age. Most of the craters are visible and consist of cinder material: scoriae and lapilli with intervening layers of volcanic bombs. Pyroclastic hecciae are also visible, as well as cineritics and base surge deposits.

At the Fontfreda cliffs, river erosion has revealed magnificent prism-shaped columns while at Castellfollit, spectacular layers of lava from different lava flows are superimposed creating a spectacular cliff with the village sited at the top. At the 17,000 year-old El Croscat volcano, the lava mass has a rough surface covered with lava blocks and numerous blisters (projecting gas bubbles).

The field study course outlined below focuses on the nature and impact of the tectonic activity upon the Garrotxa landscape and the ways in which it has significantly affected the lives of the people who live there. Students use field observations to help understand and reconstruct the eruptive processes and visit a number of contrasting sites to investigate the benefits and costs of living in a volcanic environment. A selection from these options could be provided for a one-day visit, travelling from your accommodation in Barcelona.

Day Location Time Objectives Activities Main content
Day 1 Introduction
1 Airport arrival and transfer to Santa Maria del Roure
1 Castellfollit de la Roca 2-3 hr ● To observe and interpret the way in which volcanoes have transformed the landscape.

● To reconstruct the lava flow emissions through the information provided by basalt outcrops.

● To examine the benefits and costs of living in a volcanic environment.
● Annotated sketches of basalt outcrops.

● Visit town. Annotate map to show use of volcanic materials in its construction.

● Local quarry visit.
● Interpretation of the geological history
from the basalt outcrops.

● Use of volcanic materials. The quarry uses basalt in various industrial, domestic and decorative forms.
1 Classroom 2 hr ● Introduction to Plate Tectonics in the Garrotxa Volcanic Park.

● Synthesis of information obtained during the fieldwork.
● Images to show the Castellfollit de la Roca lava flow sequences.
Day 2 Interpretation
2 Montsacopa Volcano 2 hrs ● To understand the most common type of volcanic activity the area.

● To formulate hypotheses about the Montsacopa eruptive activity.

● To reconstruct the Montsacopa eruptive processes.

● To examine how volcanoes are capable of transforming the landscape.

● To examine the benefits and costs of living in a volcanic environment.
Interpretation of the landscape. Type of eruptive activity: explosive and effusive.
Study of volcanic activity. ● Interpretation of the volcanic deposits.

● Interpretation of the Garrotxa landscape.

● Volcanoes as transformers of the landscape.
2 St. Joan les Fonts and El Boscarró 2 hr

● To reconstruct the lava flow emissions through the information provided by basalt outcrops.

● To examine the benefits and costs of living in a volcanic environment.

● Interpretation of the geological history.
from the basalt outcrops .

● Boscarró quarry visit.

● Geological processes and landforms resulting from lava flow emissions.
2 Volcano Museum, Olot 1 hr ● To understand the Garrotxa volcanic processes and identify elements of the landscape.

● Video: Garrotxa earthquakes and volcanoes.

● Geology: seismology and volcanism.

● The impact of tectonics upon the environment.

● Consolidation of the fieldwork content.

2 Classroom 2 hr

● Synthesis of information obtained during the fieldwork.

● Evaluation of student reports.

● Images to show the eruptive sequences of
Montsacopa and St. Joan les Fonts.
Day 3 Investigation
3 Classroom ½ hr Description of a volcanic outcrop.
3 La Pomareda and Croscat volcanoes 4 hrs

● To understand the geological history of the Garrotxa Volcanic Park.

● To reconstruct the eruptive activity of the Pomareda and Croscat volcanoes through information provided by the type and sequence of pyroclastic deposits and lava flows.

● To examine the benefits and costs of living in a volcanic environment.

Interpretation of volcanic outcrops.

● Interpretation of geological maps.

● Annotated sketches of the volcanic outcrops.

● Classification of volcanic rocks.

● Reconstruction of the eruptive activity and the type of volcanism.

3 Fageda d'en Jordą 2 hr ● To reconstruct the eruptive activity of the Croscat volcano through information provided by the lava flow emissions.

● To examine the benefits and costs of living in a volcanic environment.
Interpretation of blisters (tossols). ● Reconstruction of the Croscat eruptive activity and the type of volcanism.
3 Classroom 2 hr ● Evaluation of student reports. ● Images to show the eruptive sequences of
Pomareda and Croscat.
Day 4 Costs and Benefits
4 Pedra Tosca Park 2 hr ● To examine the benefits and costs of living in a volcanic environment. Interpretation of a volcanic landscape modified by humans. ● EIA
4 Depart for airport

Other Study Options

G.C.S.E.

The objective is to apply a scientific method similar to that utilised by vulcanologists to study the causes of the volcanic eruptions, the anatomy of the volcano and the nature of the volcanic rocks.Chew Valley School, November 2001: Volcanic Soils Study

  • Form hypotheses about the stages in the formation of a volcano.
  • Form hypotheses about the type of volcanic eruption that occurred.
  • Relate the eruption and seismic activity in the area to geological map data.

A Level

The objective is to analyse the environmental impact of some of the human activities, the actions taken to restore the damaged environments, and produce a management plan for the Park.

  • Introduction to the geological characteristics of the Park and the aims and values of the Natural Park.
  • Assess the value of the Park's natural resources, and the environmental impact of both cinder extraction and refuse disposal sites.
  • Study the restoration techniques used in the degraded sites.
  • Draw up a management plan which resolves the environmental issues and problems of the Park.

 

Additional Options

  • The social, economic and environmental effects of rural depopulation.
  • The causes and effects of land use changes in hill farming.
  • A case study of two contrasting villages, one declining, one growing and the implications for sustainable rural development.
  • Soil Zonation: Brown Earths, Gleys and Podsols.
  • Volcanic soils: rankers and volcanic sub-types.
  • Hydrosere study (Banyoles).