Mirima National Park

Introduction: Mirima National Park, on the outskirts of Kununurra, has spectacular rock formations. Mirima is the name given to the area by the Miriuwung people, who still live in the region and consider this area to be especially significant to their culture. It is also aptly known as the "Hidden Valley". The park is a day use area only, popular for sightseeing, walking, photography and nature observation. In daylight, the steep, broken walls of rock come alive as they reflect the tones of changing light. Geology: The sedimentary formations seen in Mirima National Park were deposited 375 to 350 million years ago, at a time when active faults were altering the landscape. Uplift took place to the south-east of what is now Hidden Valley, along the Halls Creek Fault. Most of the rocks in the Mirima National Park are sandstones washed down from the highlands by low energy braided rivers flowing across broad plains in open valleys. However, the distinctive shapes of Mirima that can be seen today were produced by uplift and erosion during the last 20 million years. Before that time, however, the rocks had been subjected to deep weathering typical of tropical climates. As a result, laterite formed a hard cap on the surface 70 to 50 million years ago. This deep weathering weakened the sandstones and made them friable, by dissolving the silica cement that binds the sand grains together. The weight of overlying rocks still holds the sand grains in place, but when this is removed, the sandstones are easily eroded. The flow of water over the surface is concentrated by any weakness or irregularities in the rock, such as cracks or joints, and rapidly erodes the narrow channels that separate the towers. The result of this erosion are the gorges and twisted valleys within a broken range. Plants and Animals: Spinifex grassland, various eucalypts and distinctive tropical tree species such as the boab and the yellow-flowered kapok bush grow in the flat lands around these sandstone outcrops. The woollybutt grows close to the cliff bases and the long-fruited bloodwood grows in the moister areas of the main valleys within the park. Agile wallabies are common at Mirima National Park and throughout the Kimberley. They are relatively large and active by day. These nervous animals may be startled by passing vehicles, their bodies remaining quite upright as they hop rapidly away. Short-eared rock-wallabies also live in the more remote parts of Mirima National Park. However, they are quite secretive. If you did manage to flush them from their day-time hiding places the usual view is of their backsides, as they bound towards the nearest rocky cover with impressive speed. Dingoes can also sometimes be seen during the day at Mirima, usually early in the morning or late in the afternoon. These well-proportioned, ginger-coloured dogs usually have white-tipped ears and tails. Echidnas also inhabit Mirima National Park, though these secretive creatures are rarely seen. Extensive diggings at the base of termite mounds and along tracks are a sure sign of their presence. Frogs, tortoises, geckoes, goannas, snakes and other reptiles can sometimes be seen, especially near the waters of Lily Creek. Birds abound in the area. Black kites, the "seagulls of the Kimberley", are often seen around towns, especially near rubbish tips. They usually forage in flocks, or perch together in trees, seeking respite from the heat. From below, the tail has a shallow fork, and is constantly moving and twisting in flight. The vegetation along Lily Creek is a good place to see finches. Double-barred finches are energetic and very sociable little birds. They often form flocks of 40 or so and feed, drink, preen and sleep huddled together in groups of up to six, crammed into a purpose-built nest. Male crimson finches are such a striking red that they appear to be dipped in paint. The female is similar but olive brown above and paler below. The white-quilled rock-pigeon is a distinctive bird of the Kimberley, being almost confined to the sandstone hills and cliffs of the region, including Mirima National Park.