The geology of Malacca, with a geological map and special reference to laterite
J. B. Scrivenor, Geologist of the Federated Malay States, published this paper in 1927 as part of the ongoing geological survey of British Malaya. It presents the first systematic geological mapping of the Malacca Settlement, with a dedicated section examining the nature, formation, and practical utility of laterite. The overarching argument is that Malacca’s stratigraphic sequence—Carboniferous phyllites, Triassic quartzite-shale, and the southern termination of the Peninsular Main Range granite—produces a distinctive tropical weathering profile in which laterite functions simultaneously as a field-mapping indicator and as a quarried building material.
Summary
The paper surveys the full geological sequence of the 720-square-mile Settlement, working from the oldest rocks upward. The Carboniferous phyllites and altered calcareous rocks form a narrow belt between the Malacca granite and the Johore granite of Mt. Ophir; the Triassic quartzite-shale appears in two outcrops, one of which is largely conjectural. The granite, intruded into both older groups, constitutes the southern end of the Main Range and is mapped as a continuous outcrop from the northern hills to the coastal islands, though in the central area (Kesang, Ayer Panas, Bemban) numerous small intrusions into stratified rocks are too numerous to separate at the map’s scale. Recent deposits—alluvium, beach-sand, and laterite—complete the sequence. The mineral section addresses three categories: old gold-workings near Asahan (now extinct), active tin-workings in the Kesang and Chin Chin areas, and tin-ore on the coast and sea-bed derived from a small aplite outcrop near the Linggi River mouth.
The laterite section constitutes the paper’s principal original contribution. Scrivenor traces the term to F. Buchanan’s 1807 description of indurated clay in Malabar, then engages the 1909–1912 debate in the Geological Magazine over whether “laterite” should be restricted to aluminous weathering-products. He argues that the name had become popular among engineers and builders in the tropics and should be understood as a ferruginous weathering-product, with the rarer aluminous varieties designated separately as “aluminous laterites.” In Malacca specifically, he contends that Buchanan’s original sense—indurated clay quarried and cut into building blocks—is the only context in which the name is “absolutely correctly applied,” citing the Portuguese use of laterite blocks in St. Paul’s Church and their continued use by Malay householders.
Primary evidence takes the form of field observations from two campaigns (1906 and 1926), the 1916 territorial map at 1 inch = 1 mile from which the published geological map was reduced, and chemical analyses of laterite and black-sand samples. The phyllite-limonite relationship is established through the preservation of original bedding structure within laterite masses, a feature Scrivenor identifies as a valuable mapping guide where unweathered rock is not visible.
Key Findings
- The Settlement’s area is 720 square miles with over 250 miles of roads; the northern granite hills reach 1,304 ft (Bukit Punggor) and 1,419 ft (Bukit Batang Malaka), while the adjacent Mt. Ophir in Johore rises to 4,187 ft (p. 276, 278).
- The Chabau altered calcareous rock forms a belt approximately three miles wide between the two granites; its chief constituents are quartz, calcite, garnet, pyroxene, wollastonite, biotite, and pyrite, and Scrivenor identifies it as intensely altered limestone (p. 277).
- Black sand collected near Tanjong Dahan yielded, after quartz removal, 82.4% magnetic fraction (ilmenite, tourmaline) and 9.6% non-magnetic fraction (rutile, anatase, zircon, cassiterite); the original sample assayed at 0.29% tin, equivalent to roughly eight katis per cubic yard (p. 280).
- A laterite block quarried near Bukit Piatu and analysed by Mr. J. C. Shenton contained: silica 23.60%, ferric oxide 37.94%, alumina 21.60%, water and loss on ignition 11.20%—confirming a predominantly ferruginous composition with alumina mostly as hydrated silicate (p. 287).
- Light-coloured aluminous nodules from the same locality contained 1.04% silica and 41.14% alumina soluble in hydrochloric acid, demonstrating that true aluminous laterite does occur but in quantities too small for commercial extraction (p. 287).
- Buchanan’s 1807 definition of laterite as indurated clay cut into bricks (“brick stone,” Itica cullu) is the basis for Scrivenor’s argument that the term in Malacca should retain its original practical sense rather than be narrowed to aluminous deposits (pp. 281–282).
Conclusion
Scrivenor’s definitive historical takeaway is twofold. First, the term “laterite” in Malacca is uniquely and correctly applied in Buchanan’s original sense—to indurated clay quarried for building—making Malacca the only part of British Malaya where the name carries its full etymological weight. Second, the Malacca laterites are overwhelmingly ferruginous (hydrated iron oxide) rather than aluminous; while small aluminous nodules exist, the prospect of finding bauxite in commercially viable quantity on the Peninsula is “very remote,” and even the iron-rich laterite at Chin Chin could not be worked to produce iron more cheaply than imported ore at the time of writing.
Context
- The paper is based on two field campaigns (1906 and 1926) and is reduced from the 1916 map of Malacca Territory; it constitutes the first published geological map of the Settlement and was produced as part of the systematic survey of British Malaya (p. 276).
- The laterite discussion engages directly with the 1909–1912 correspondence in the Geological Magazine and with C. S. Fox’s 1923 memoir for the Geological Survey of India, positioning Malacca’s ferruginous laterites within the broader tropical weathering literature (pp. 281–283).