More on the Malay Geology and Prehistory

Regarding the Malay Peninsula, which at least one reader seems to champion beyond the level of reason, fact, and reality, the Titiwangsa Mountains (Benjaran Titiwangsa) are part of the Tenasserim Hills system, a suture joining together along a major fault zone, of separate terranes; tectonic units that have different plate tectonic metamorphic and paleogeographic histories that form the backbone of the Peninsula. The northern section of the range in southern Thailand, where it is known as the Sankalakhiri Range, runs north to south for 300 miles and acts as a natural divider, dividing peninsular Malysia, as well as southernmost Thailand, into east and west coast regions. These mountains are not recent, being granite and limestone dating to the Permian, Triassic Period. 
   This mountainous backbone of the Malay peninsula shows a solid connection from far into the mainland clear down to the southern tip of the peninsula and that, as geologists point out, would not have allowed for the peninsula to have ever been separated.

Top: Titiwangsa Mountains running along the backbone of the peninsula; Bottom: The Kra Isthmus, the narrowest and lowest point along the peninsula in southern Thailand and Myanmar

The Kra Isthmus, with the east part of the land bridge belonging to Thailand, while the west part belongs to the Tanintharyi division of Myanmar, runs between the Andaman Sea to the west of the isthmus, and to the east the Gulf of Thailand, with the narrowest part located between the estuary of the Kra River and the Bay of Sawi near the city of Chumphon. At this point, the width is 27 miles, and the Phuket Range (a continuation of the greater Tenasserim Range, forming one of the southern sections of the central Indo-Malay cordillera, the mountain chain which runs from Tibet through all of the Malay peninsula extending southwards for over 125 miles) having an elevation of 246 feet above sea level.
    This means that the ocean in Indonesia, which would include the Pacific Ocean and the Indian Ocean would have had to have been about 260 feet higher than today for this separation of the southern peninsula to have been an island at any time, and that would leave only an island 840 miles long across the Malacca Platform—hardly sufficient for the entire history of the Jaredites, Nephites and Lamanites to occupy.
    However, what geologists tell us is that the Indonesian area was actually higher at one time with ocean levels much lower than now. In fact, according to T. Tomascik, et al, Sundaland, or the Sundaic region, land bridges connected the islands of Borneo, Java, and Sumatra to the Malay Peninsula and mainland Asia, corresponding to a larger landmass that was exposed throughout the last 2.6 million years during periods when sea levels were lower. It includes the Malay Peninsula on the Asian mainland, as well as the large islands of Borneo, Java, and Sumatra and their surrounding islands (T. Tomascik, J.A. Mah, A. Nontji, and M.K. Moosa, M.K., The Ecology of the Indonesian Seas – Part One. Hong Kong: Periplus Editions, Hong Kong, 1996, pp580–581).
    In fact, the area of Sundaland encompasses the Sunda Shelf, a tectonically stable extension of Southeast Asia’s continental shelf that was exposed during glacial periods of the last 2 million years (Mark de Bruyn, Björn Stelbrink, Robrt J. Morley, et al, “Borneo and Indochinas are Major Evolutionary Hotspots for Southeast Asian Biodiversity,” Systematic Biology, Vol 63 (6), 2014, pp879-901)

The Sahul Shelf and the Sunda Shelf today. The area in between is called Wallacea—at one time, shown in the grayed area, far more land was above water, forming a connecting land bridge between several of these major islands and the Malay Peninsula, as well as between Australia and Papua New Guinea

In fact, greater portions of Sundaland were most recently exposed during the last glacial period ending about 12,000 years ago (Lawrence R. Heaney, "Mammalian Species Richness on Islands on the Sunda Shelf, Southeast Asia," Oecologia, Vol 61 (1), 1984, pp11-17), when land bridges connected the islands of Borneo, Java, and Sumatra to the Malay Peninsula and mainland Asia (Till Hanebuth, Karl Stattegger, and Pieter M. Grootes, "Rapid Flooding of the Sunda Shelf: A Late-Glacial Sea-Level Record," Science, Vol 288 (5468), 2000, pp1033-1035).   
    Geologic studies have shown that entire submerged river systems are observable beneath the oceans of the Siam River System, Malacca Straits River System, North Sunda River System and the East River System, all at one time flowing above the surface on the ancient lands.

Drawing of the raised coast lines in South-East Asia and now submerged river systems—the river beds are based on the surface contours of the sea bed in the area 

    In addition, according to Harold K. Voris: The Paleo River Systems of the Sunda Shelf are vast submerged river systems that extend present-day river systems and may be interpreted to follow topographic lows in a down-slope direction. During the driest of the Pleistocene era, about 17,000 years ago, some four distinct catchment areas formed the Malacca, Siam and Sunda River Systems ("Maps of Pleistocene sea levels in Southeast Asia shorelines, river systems and time durations," Journal of Biogeography, Field Museum of Natural History, Chicago, Illinois, Vol 27, 2000, pp1153–1167). 
    It should be noted that at one time Borneo and Sumatra were continuously connected as a single landmass to the Malaysian Peninsula except for a possible brief period when the land bridge to Borneo may have been temporarily severed. Java would not have become fully connected to Sumatra until much later when the deep, narrow channel through the Sunda Straits existed. In fact, as is the case today, the highland areas of Sundaland occurred as a long arc of volcanic mountains fringing the southern and southeastern margin of the continent in Sumatra, Java and Bali, as extensive highlands in central and northern Borneo, and down the spine of the Malaysian peninsula. 

The Indonesian Throughflow is a current movement of warm water off the tropical Pacific Ocean moving westward through Indonesia and between Malay Peninsula and Sumatra and into the Indian Ocean

One of the things that seems lost on the supporters and proponents of the Malay theory is that the rise in water levels surrounding the Indonesian area, and the Indonesia Through Flow (from the Pacific to the Indian Ocean), is that this rise only submerged the land bridges between the Malay Peninsula and these numerous islands to basically what they are today. In fact, according to Michael I. Bird, of the School of Earth and Environmental Science and Center for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Queensland, Australia, the Malaysian Peninsula has been subsiding, and the land bridge south of the Malaysian Peninsula across the Straits of Singapore to the Riau Archipelago was never submerged prior to the Last Interglacial, and since that time had been submerged only for short periods (Micael I. Bird, et al, “Palaeoenvironments of insular Southeast Asia during the Last Glacial Period: A savanna corridor in Sundaland, 2005).
    These connections relate to several interstadial sea-level highstands or lowstands following the Last Interglacial and during the last glacial period. Of particular note is the existence of a flat widespread surface, interpreted as a marine abrasion terrace, identified in the vicinity of both Banka and Karimata Islands, that is, along the axis of the land bridge to Borneo (G.J.J. Aleva, “A Contribution to the Geology of Part of the Indonesian Tinbelt: the Sea Areas Between Singkep and Bangka Islands and Around the Karimata Islands,” Persatuan Geological Malaysia, 1972).