Welcome to Lata Iskandar
This EarthCache invites you to visit the waterfall at Lata Iskandar and learn how the bedrock shapes the falls, the stream channel, and surrounding soils. The site exposes coarse‑grained granite that the stream has cut into, producing blocky cascades, boulder beds, and sandy regolith.
Underlying Rock at Lata Iskandar
Lata Iskandar sits on the western flank of the Main Range where the dominant bedrock is the Triassic Main Range Granite. The waterfall and its immediate channel are carved into a coarse, jointed igneous rock composed mainly of quartz, feldspar, and mica.
The granite here is resistant to erosion relative to nearby sedimentary units, so the stream forms stepped cascades and plunge pools where joints and fractures concentrate erosion. Weathering of the granite produces a sandy, acidic regolith that feeds the stream with rounded granite cobbles and sand after heavy rains.
Small patches of sedimentary veneer or tectonic breccia may occur locally, but the practical geology visible at the falls is granite; joint spacing, blocky weathering, and the presence of quartz‑rich boulders are diagnostic field indicators. For engineering or scientific work a site reconnaissance or a geological map of the Tapah–Lata Iskandar sheet will confirm local contacts, but for visitors the rock you can touch and photograph at the falls is granite.
Coarse‑grained S‑type Granite
Coarse‑grained S‑type granite is a plutonic rock that crystallized slowly at depth, producing visible, interlocking crystals of quartz and feldspar with flakes of mica. The S‑type designation indicates a sedimentary source for the melt: metasedimentary rocks such as pelites and greywackes partially melted during crustal thickening to produce a peraluminous magma. Peraluminosity means there is excess aluminium relative to alkalis and calcium, which stabilizes aluminous minerals; muscovite, garnet, sillimanite, or cordierite can appear as diagnostic phases in thin section. Texturally the rock is phaneritic, with large crystals that record slow cooling and emplacement as a pluton or batholith. Field expressions include blocky jointed outcrops, coarse boulder beds in streams, and thick, sandy regolith where the granite weathers in a humid climate. Petrologically, S‑type granites carry isotopic and geochemical signatures that point to crustal, sedimentary provenance rather than mantle input; in the field this translates to abundant quartz, feldspar, and aluminous accessory minerals and to soils that are acidic and low in carbonate.
How to claim this EarthCache?
For this EarthCache, I recommend taking the stairs on the right side of the falls. From there, you can observe the waterfall and its surroundings, and it will lead you to a platform where you can make additional observations and snap a cool photo for your log. While you're there, check out GC7RAH1.
Email me the following;
1. The text "GCBH5HA Lata Iskandar" on the first line.
2. The answers to the following questions;
- What is the dominant bedrock at Lata Iskandar and how does it influence the waterfall's form?
- What field indicators would confirm that the exposed rock is granite rather than shale or limestone?
- Examine the exposed faces and fallen blocks. Do you see planar fractures or blocky jointing, and how do these features control the waterfall geometry?
- Look at the stream sediment in a shallow pool. Is the sediment dominated by sand, angular fragments, or rounded cobbles, and what does that reveal about transport and source?
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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