Valley of the Jerte: Spanish cherries and the Jurassic Period.
In the Gredos Mountains, there is a river valley that looks surprisingly straight on the map. That's no coincidence. The Jerte flows along Spain's largest fault line. And there are a lot of cherries to pick.
A valley with a microclimate on Spain's largest geological fault line
Text 2016 © Kathelijne Bonne.
In Spain, it is a well-known fact that the best cherries of the peninsula, the cereza picota, come from Extremadura and, more specifically, from the Valle del Jerte in the province of Cáceres. This unique place on the southern slopes of the Gredos Mountains receives a wave of visitors, twice a year. In the spring the 'cerezos' (cherry trees) are in bloom, which results in beautiful idyllic panoramas. In the summer the trees are heavily laden with different varieties of picota cherries.
Hordes of Madrileños then book an all-in formula: one day by bus to and fro to pick as many cherries as one can carry and to attend the 'feria de la cereza picota and cereceras', all kinds of activities and festivities related to the cherry-picking. But the Valley of the Jerte is more than just a hotspot for these fruity delicacies.
The Jerte River flows in a straight line to the city of Plasencia in the southwest, to eventually join the Tagus that flows towards Lisbon. The Jerte is hence one of the many tributaries forming the Tagus river network, Spain's largest river basin.
More interestingly, the Jerte runs along one of Spain's, and even Europe's largest geological fault lines, running all the way southeast to Alentejo in Portugal. This Alentejo-Plasencia fault was formed 200 million years ago at the start of the Jurassic Period.
Before the Jurassic, Spain, or in fact Iberia, was part of the supercontinent Gondwana. In this continent, Africa and South America lay next to each other, but it also comprised parts of Europe, including Iberia. In Jurassic times, a large rift zone developed between what is now South America, Northwest Africa and Iberia. In a rift zone, tectonic forces act in different directions, dragging along parts of continents, while a new ocean, in this case, the Atlantic, widens between them. As such the separated continental 'blocks' became the continents that we now recognize on the world map.
This whole continental break-up process was accompanied by enormous tensions on the Earth's crust. At some places, the crust ruptured and at such locations, fault lines formed. Some of these faults filled with magma. The Alentejo-Plasencia fault is one of the largest faults that formed during this process.
A magmatic rock called dolerite can be found everywhere along the riverbed of the Jerte, as a silent witness to the prehistoric violence of nature. According to geologists, the fault line is still active and could sooner or later undergo an earthquake. Or in other words, tensions in the crust can be released along this fault, as any fault always remains a weak spot. Furthermore, rivers are more likely to carve their path along a zone of weakness and fractures, which is why many rivers run along faults, like the Jerte.
The Valle del Jerte is best visited in June when it's cherry season. There is a microclimate so it is warm during the day and pleasantly cool and fresh in the late hours. From Madrid, the Valle del Jerte is reached by passing past Ávila, and over the Tornavacas mountain pass, after which the track winds down along several hairpin turns. This is the border between Castilla-Leon and Extremadura.
There are natural plunge pools, carved out by loose boulders in fast-flowing streams since the last Ice Age.
Thanks to its mild climate and unique landscape, the valley lends itself to all kinds of natural activities. Walking along small streams and waterfalls, picnicking on beaches and swimming in the Jerte, mountain biking and wildlife watching are some of them. You can stumble upon many species such as birds of prey, otters, wild cats and even the genet.
At Cabezuela de Valle, which hosts an information center, some larger beaches are nestled in a wide bend of the Jerte. In the gorge of the Garganta del Infierno, a tributary of the Jerte, there are natural plunge pools, carved out by loose boulders in fast-flowing streams since the last Ice Age.
To recover from active days, you can have dinner in one of the several villages along the river or on the mountain flanks. During the días gastronómicas de la cereza the most incredible combinations of cherries, used in typical Spanish dishes, are prepared. There are of course many shops where all kinds of cherry related products can be found, jams, liqueurs, biscuits, gazpacho, tea, and of course, large boxes full of delicious shiny, fresh cherries.
- Gonzalo Riestra on WikimediaCommons / CC BY 2.0
Foto-Ardeidas on WikimediaCommons / CC BY-SA
Luis Fernández on WikimediaCommons / CC BY-SA 2.5 ES
Other photographs by Kathelijne Bonne.
Valle del Jerte.
The Valle del Jerte is located between Tornavacas and Plasencia in the province of Cáceres of the region Extremadura.