The Northern Loop to Mammoth Hot Springs Part 1

Saturday

After our rest day we opted to do the Northern Loop Road to visit Mammoth Hot Springs (MHS). We were fortunate in meeting very little traffic on the way, it being Saturday and all. Now that the sun was shining we revisited  the Le Hardy Rapids and found some Harlequin Ducks swimming in the fast flowing water.

We then sped up the Hayden Valley, cut along to Norris and up to MHS.

You enter this section of the Park via a very narrow gorge, where the road has been literally built on a cliff face – like a concrete  bridge supported at the side rather than below. This was originally built of wood in the 1930’s, before that the journey south took an extra half day to go round a longer way. The initial view as you drive down here is stunning, with the gorge walls on either side, a waterfall behind and Mammoth Hot Springs in front of you and sets the tone of expectation for things to come.

Ignoring all stops we drive straight into MHS to find a morning cuppa and the restroom. Of course being Saturday MHS is complete chaos. Because it is kept open all year round it is the administrative  HQ for the park, which is housed within MHS in Fort Yellowstone. The public bits appear quite limited. The general store is very small, and the most obvious eating place is the grill (think MacDonalds without Ronald), when we arrived there were only a dozen people waiting, when we left the line was out of the door. Once re-energized and relieved we returned up the road to the hot springs.

The central attractions of MHS are the hot springs and Fort Yellowstone (which we ignored as we did not have time to visit both).

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(If easily bored then please miss out the next two paragraphs)

The unique factor about these hot springs is that deep underground the superheated ground water passes through a thick layer of limestone as it is forced to the surface, so is rich in dissolved Calcium Carbonate. On welling out onto the surface it depressurizes and cools, forcing the Calcium Carbonate to come out of solution as a mineral called Travertine, which is essentially the same as the form of Calcium Carbonate which forms Stalagmites in caves. Except in caves the deposits are measured in millimetres per century, here in the open air with the high concentrations of mineral due to heat and pressure the deposits can be measured in millimetres per year.

As the water emerges , often with very small springs, the water forms puddles or pools, the Travertine deposits more rapidly at the edge, building a little wall round the pool, enabling the pool to be a little bit deeper before it overflows, this lets the wall build higher. The effect is a number of pools which form terraces as the water flows down the hillside. The water contains Thermopiles (bacterial and algae) which give the Travertine a range of colours. As the level of the pools builds up the water may find a different pathway, so some terraces are abandoned and new ones constructed. I assume that the Travertine has an H2O content to produce this mineral form (like calcite), so after a period of exposure (several years) the Travertine reverts to Calcium Carbonate, more like chalk. These chalk formations may be several hundred feet thick, with the dramatic, rapidly changing, multi-coloured, flat terraces with little walls round them.

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With lots of shiny surfaces and water the effect is amazing. We started at the Upper Terraces and using the handicapped accessible boardwalks wandered in amazement at the wonderful effects that such a simple recipe could produce. As usual pictures do not show this, they simply record  it, leaving the memory to fill in the wonder element.

By the Upper Terrace Boardwalk we had our lunch and then took the drive round the loop road past several other Travertine formations, which also passed through some very pretty flower meadows.

We then descended back towards MHS and explored the Lower Terraces. We then stopped back in to the Grill for an early meal before completing the Northern Loop Road.