Type of EarthCache: Karst landscape, general knowledge.
Kinta Valley karst
Karst is a terrain with distinctive hydrology and landforms arising from a combination of high rock solubility and well developed secondary porosity (Ford and Williams, 1989). The rate of karstification is always thought to be fastest where the climate is wettest. Because of this assumption, much of the Malaysian karst is thought to be in the mature stages of karstification (Crowther, 1989; Ros Fatihah Muhammad and Yeap, 2001).
The subsurface landform has evolved into pinnacles acting as pockets and trapping the tin-rich placers. The uniqueness of the Kinta Valley karst lies mainly, among others, on the spectacular shape of steep-sided limestone towers which protrude from the vast alluvial plain. The formation of this tower karst is made possible by various factors, namely: the humid, wet tropical climate, accelerated karstification and its location in the floodplain of Kinta. The floodplain location of the karst ensures a constant supply of allogenic water to the karst which promotes the karstification processes.
During the course of karst development, wangs or closed depressions were formed. Normally surrounded by vegetated steep walls and sometimes filled with water to form lakes, wangs easily draw the attention of nature lovers. Within the karst, cave systems with magnificent cave deposits are numerous and accessible. The Kinta Valley karst also acts as nature's vault preserving and safeguarding the records of the history of the paleoclimate, archeology and culture (Ros Fatihah Muhammad and Yeap, 2001). Besides being aesthetically appreciated, caves which are located at the foot of some limestone hills have drawn the attraction of Buddhist and Hindu worshippers.
View over Tasik Cermin, also known as Mirror Lake.
The wang is surrounded by steep karst formations.
(Source: Barnyard Dawg, 2018)
Geology
Geologically, the Kinta Valley is underlain by the Kinta Limestone which has been dated Devonian to Permian (Suntharalingam, 1968). The limestone includes several relatively thin argillaceous beds, and exceed 3000 metres in stratigraphic thickness (Ingham and Bradford, 1960). Much of the limestone is found beneath the general surface where it underlies the tin ore bearing alluvium for which the Kinta Valley was once famous. The Kinta Valley Schist occurs mainly below the Kinta Limestone though parts are found to interbed with the former (Ingham and Bradford, 1960).
The limestone and schist were probably folded and metamorphosed during or near the end of the Permian. After the folding and metamorphism, these Paleozoic rocks (limestone and schists) were intruded by the Kledang and Main Range Granites during the very Late Triassic. Some Jurassic igneous events have been detected as well. After the folding and intrusive events the limestone slowly became emergent. Calculated rates of emergence is estimated at 0.1 mm per annum (Krahenbuhl, 1991). The Padang Rengas limestone is interpreted to be the northern most extension of the Kinta Valley Limestone and its surface expression formed of Gunung Pondok.
Gunung Rapat
Gunung Rapat is arguably the most famous limestone hill in the Kinta Valley. Its close proximity to Ipoh town and its spectacular shape with attractive features are appealing to many visitors. Some characteristics that made Gunung Rapat important are;
— The limestone tower. Geomorphologically, Gunung Rapat show cockpit type topography - with many peaks and a number of collapsed, dry and water-filled wangs. The highest peak is 318m high and has basal area of 4.6 km². In plan view it is highly irregular in shape with many appendages sticking out of the whole hill like an amoeba. The steep-sided wall, sometimes almost vertical of the hills rise from the flat alluvial plain give a spectacular view to this hill.
— Caves. Caves are numerous at Gunung Rapat. The most important types are the foothill or notch caves commonly located at the base of the hill. These caves are very accessible and house various temples of Buddha and Hindu believers. Two famous temples found in Gunung Rapat are the Sam Poh Tong and Kek Look Tong. Five levels of caving measured in this hill are located at about 184.9 m, 138.4 m, 102.4 m, 87.7 m and 80 m above mean sea level. These levels are thought to be records of base level lowering.
— Notches. Gunung Rapat is located in an alluvial plain and frequent flooding of the plain give rise to swampy condition at the base of the hill. Ponds are scattered around the foothill and inside wangs. Lateral dissolution by pond water on the walls of the hills produced notches. Therefore, notches where preserved are the reliable records of previous base level. In Gunung Rapat, the best developed multi-level notches were observed, locality is found in a wang on the western part of Gunung Rapat which preserved a record of the past climatic conditions for the last 135,000 years.
— Pinnacles. In some areas, where mining operations have stripped off the alluvial cover, it has been observed that the original limestone platforms have been reduced to pinnacle topography by sub-surface solution. Elsewhere, mining activities of rich iron-bearing alluvium have exposed hitherto hid!ien important sub-surface morphology such as the planation of buried limestone at about 9 m below the floodplain level which can be seen in an open wang at the western part of the hill. The once-buried limestone forms a platform with an almost horizontal surface and, when it was subjected to downward dissolution, it formed pinnacles. Therefore, limestone platform and the pinnacles are important in understanding karst evolution.
— Wangs. During the karstification process of the limestone outcrop, areas that are located in the intersection of several fracture systems were always dissolved faster and developed into wangs or closed depression. Wangs are always filled with tin-rich alluvium and where they were formerly mined, ex-mining ponds were left behind. The appearance of wangs is always as a flat plain surrounded by either almost vertical bare wall due to natural collapse or by steep wall with lush vegetation. A wang in Kek Look Tong cave has been developed into a recreational park.
View over Tasik Cermin, also known as Mirror Lake.
The karst formations suffer significant notching.
(Source: Barnyard Dawg, 2018)
How to claim this EarthCache?
The idea behind this easy EarthCache is to try and recognise some of the features you are looking at. After reading the listing, observe your surroundings, and answer the question.
Send me the following;
1. The text "GC7RAGZ Mirror Lake - Karst Features" on the first line.
2. The answer to the following question;
- How many of the above mentioned karst features can you identify from the platform?
3. Provide a photo of yourself or a personal item to prove you have visited the site.*
References
* Effective immediately from 10 June 2019, photo requirements are permitted on EarthCaches. This task is not optional, it is an addition to existing logging tasks! Logs that do not meet all requirements posed will no longer be accepted.
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