In the Ancient Peaks Soil Series, we explore the unique diversity of soil types found at our estate Margarita Vineyard. Today we take a look at the Monterey Shale of Margarita Vineyard.

The Monterey Shale deposits at Margarita Vineyard are concentrated along the northwest border of our ranch, where the vineyard blocks are planted to Cabernet Sauvignon, Zinfandel, Syrah and Pinot Noir.

And while not quite as dramatic our fossil-riddled sea bed soils, our Monterey Shale deposits are still a sight to behold.

Soil trenches in these blocks reveal deep, densely packed layers of wafer-like shale rock, gray in color with streaks of reddish orange. The thinner wafers crumble in the palm with minimal force. One can only marvel at how the vine roots manage to work their way through these rocky beds in search of moisture and nutrients.

Lower Yields, Intense Flavors

So how deep do these shale beds go? “Thousands of feet, and I’m not kidding,” says Ancient Peaks co-owner and viticulturist Doug Filipponi. “The shale is fractured, however, so you’ll get these deep, willowy vine roots winding their way down through it. It’s a difficult soil, which ultimately produces high-quality fruit.”

Monterey Shale is a formation unique to the coastal areas of central and southern California. As one expert tells it, “The Monterey formation…has been generated over millions of years by the conversion of tiny, dead marine organisms, known as diatoms, into hydrocarbons.”

The abundantly rocky deposits in our Monterey Shale blocks create wines with excellent flavor concentration and complexity. “The most dramatic attributes of these blocks are small clusters and small berry size,” Doug says. “There’s not a lot of nutrition in this soil, which makes it hard on the vine to produce, resulting in lower yields with intense flavors.”

Taste It: 2020 Cabernet Sauvignon

The latest vintage of our flagship estate wine comes from six blocks at Margarita Vineyard, including blocks 49 and 50, which are rooted in a combination of ancient sea bed and Monterey Shale soils. These blocks yield a classic Cabernet profile with excellent concentration and a mixture of red and black fruits. The 2020 Ancient Peaks Cabernet Sauvignon opens with heady aromas of black raspberry, cherry, sage and tobacco leaf. A juicy, mouthfilling texture reveals seamless layers of currant, cherry, blueberry, dark plum and black olive with trailing hints of mocha, mineral and eucalyptus. Suggestions of vanilla bean join soft tannins on a smooth, rounded finish. Find it at our tasting room or acquire it from our web store.

Monterey Shale (middle row) from Margarita Vineyard