The Geology of Esporão’s Estate soils

The Geology of Esporão’s Estate soils

In 2008, we initiated a transformation in our production process. Driven by our inherent curiosity and our mission – to make the best products from what Nature provides in a responsible and inspiring manner -, we pay increasing attention to every detail.

During this journey, we realised the importance of knowing our soils and their characteristics in order to optimise our routine agricultural management practises, such as soil analysis, irrigation water management and restructuring plots of vineyards, among others.

For this, it was crucial that we carry out a geological map of Herdade do Esporão’s vineyards, developed by geologist José Borrego.

Our intention was to obtain a detailed map that enabled us to identify the terrain’s lithological (or “rock”) variations in the plots of vineyards, and associate this data with qualitative information of the grapes. We wanted to understand if there were any relatable geological characteristics in the plots intended to produce  premium wines, a work that is still ongoing. Furthermore, we wanted to obtain a deeper understanding of the terroir of Herdade do Esporão’s vineyards and the relevant characteristics that distinguish them from the rest of the Alentejo winegrowing region.

Herdade do Esporão’s vine-growing areas have an extensive history. Therefore, while developing this work in the field, we discovered some well-kept secrets.

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The most ancient rocks found – Barrancos Schist Formation – originated from seabed sediments formed approximately 500 million years ago.

At the time, volcanic materials were deposited on the seabed, namely São Marcos do Campo Volcano-Sedimentary Complex. Later, between 400 and 280 million years ago, intense tectonic and volcanic activity culminated in the formation of an ancient mountain range: the Variscan orogenic belt (that extended from the current Gulf of Mexico to Eastern Europe).

Over time, the sediments that settled on the seabed transformed into schist metamorphic rocks. Along with this, intense magmatic activity occurred which brought about the installation of intrusive igneous magma and, later, the Reguengos de Monsaraz Eruptive Matter, approximately 300 million years ago.

Today we know that the current relief formation, combined with the weathering of rocks and consequent soil formation, essentially reflect the geological and climatic phenomena that took place in the last 2 million years.

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Amostra dos sete solos da Herdade do Esporão: Corneanas Pelíticas
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Amostra dos sete solos da Herdade do Esporão: Dioritos
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Amostra dos sete solos da Herdade do Esporão: Filões Aplito-Pegmatíticos
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Amostra dos sete solos da Herdade do Esporão: Granodioritos e Tonalitos
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Amostra dos sete solos da Herdade do Esporão: Metapsamitos e Metapelitos Cinzentos
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Amostra dos sete solos da Herdade do Esporão: Metapsamitos e Metapelitos Vulcanoclásticos
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Amostra dos sete solos da Herdade do Esporão: Xistos Mosqueados
The vineyards at Herdade do Esporão are located in a circumscribed area measuring approximately 10 km², where there is a considerable number of geological units made up of metamorphic rocks of volcano-sedimentary and magmatic rock origin. A great lithological diversity that makes Herdade do Esporão unique.

We also found that the rocks used as signage on the main roads, indicating Wine Tourism, Wineries, Mill and other points of interest, are of dioritic nature. Rocks whose presence seems to be limited to Herdade do Esporão and which occasionally coincide with some of the plots intended to produce premium red wines.

Out of curiosity, we discovered that if we divide the vineyard area into two halves, we find a probable fault zone extending North – South, running along the airstrip until, at least, the vicinity of the Esporão Tower. Generally, fault zones coincide with areas of groundwater circulation in the subsurface environment. Therefore it is likely that the relative abundance of water, along with the maturity of the surrounding soils, may have been decisive to medieval occupation and, consequently, construction of the Esporão Tower.

All of this work led us to conclude that the inherent terroir of the Estate’s vineyards is characterised by its geological diversity, where magmatic igneous rocks predominate.