Macedon Ranges – high times

It was fascinating working on the background research for the Macedon Ranges region, preparing the technical notes for Mount Monument. It is such an interesting geology: the region lies on Ordovician (510-439 million years old, when the first vertebrates appeared) and Silurian (439-409 million years ago) sedimentary rocks from east of Ballarat to east of Mount Macedon. These are bounded on the east by the Cambrian Heathcote greenstone belt, intruded by Devonian granite rocks forming the Cobaw ranges and tertiary basalts and trachytes due to volcanic activity.

The Ordovician and Silurian sandstones and shales are acidic duplex shallow brown-yellow clay loams of low fertility. The granites of the Cobaw and steeper slopes of Mount Macedon are mostly free draining sandy to stony loams. The soils around Romsey, to the south and east of Gisborne and around Woodend are rich gradational sometimes red friable clayey soils, volcanic in origin and frequently found in contact with the Ordovician and Silurian duplex soils along old stream valleys.

Macedon Ranges is also breathtakingly high. At 600 metres, Mount Monument is one of the highest points of the region, to the east of Mount Macedon in the shadow of Mount Monument, a mamelon formed 6.25 million years ago (at the same time as Hanging Rock) by the venting and cooling-in-place of thick, silica-rich, soda-trachyte magma (demonstrating plate tectonics).

An altitude of 300–700 metres above sea level, Heat Degree Days 970–1050 and harvest between mid-March to early June make the region ideal for complex and early-ripening Pinot Noir, Riesling, Chardonnay. It is the coolest winemaking region in mainland Australia, with summertime Mean January Temperature (MJT) of 17.2 to 18.5°C, which is in the same range as the coolest wine climates of Champagne, Chablis, Tasmania and Rheingau.

No doubt why the region produces some of the highest quality Chardonnay, Pinot Noir and Riesling in the country.