Malay-Thai Peninsula Research Articles

Glacial Isostatic Adjustment modelling of the mid-Holocene sea-level highstand of Singapore and Southeast Asia

The mid-Holocene sea-level highstand refers to higher-than-present relative sea levels (RSLs) in far-field regions between 7000 and 4000 years ago because of equatorial ocean syphoning and continental levering. But the timing, magnitude, and spatial variability of the highstand are uncertain and the highstand parameterization in Glacial Isostatic Adjustment (GIA) modelling is understudied. Here, we use the RSL records of Southeast Asia to investigate the sensitivity of the mid-Holocene highstand properties to Earth and ice model parameters, including lithospheric thickness, mantle viscosity (both 1D and 3D), and deglaciation history of Antarctica and global ice sheets. We found that the Earth model variation only affects the magnitude of the mid-Holocene highstand unless extraordinary low upper mantle viscosity is used. The timing of the highstand moves towards present and there is an absence of the highstand if upper mantle viscosity is < 4.0 × 1019 Pa s or ≤ 1.0 × 1019 Pa s, respectively. Ice model variation changes both the timing and magnitude of the mid-Holocene highstand. Delaying the ice-equivalent sea level will shift the timing of the highstand later and result in a lower highstand magnitude. We produced a mid-Holocene highstand “treasure map” that considers topography change and accommodation space to guide future RSL data collection efforts in Southeast Asia. The highstand “treasure map” indicates that the northeast and central west coast of Malay-Thai Peninsula, east coast of Sumatra, north coast of Java, and southwest coast of Borneo are very likely (90% probability) to preserve mid-Holocene highstand evidence.

Provenance of Oligocene–Miocene sedimentary rocks in the Cuu Long and Nam Con Son basins, Vietnam and early history of the Mekong River

The offshore Cuu Long (CLB) and Nam Con Son (NCSB) basins of SE Vietnam are two important Cenozoic hydrocarbon-bearing basins in the southern South China Sea (SCS), which can contribute to understanding the evolution of major SE Asian river systems, in particular the Mekong River. The Oligocene to Early Miocene basin fill of the Cuu Long Basin is dominated by sediment sourced locally from the Da Lat Zone basement on land. Sandstones have abundant Cretaceous detrital zircons and heavy mineral assemblages dominated by apatite and epidote. The Bach Ho Unconformity at c. 16 to 20.5 Ma marks a major provenance change and the overlying Middle to Late Miocene Con Son and Dong Nai formations were sourced by a large river system, which drained Indochina or even the Himalaya, resembling the present-day Mekong River. These formations have heterogeneous detrital zircon populations dominated by Triassic ages and zircon–rutile–tourmaline-dominated heavy mineral assemblages. The Oligocene Cau and Early Miocene Dua formations of the Nam Con Son Basin have a similar provenance to the CLB Con Son and Dong Nai formations, indicating a comparable drainage history of a large proto-Chao Phraya. At the Dua Unconformity at c. 15.4 to 17 Ma the Indochina provenance signature changes to a predominant Sibumasu signature.The early Mekong River evolution is suggested to have involved two river systems. A proto-Mekong 1 initially filled the CLB, while at the same time a proto-Chao Phraya River with a capture area into the Himalaya filled the Malay Basin and/or the NCSB. At the end of the Early Miocene drainage was completely reorganised, and the proto-Mekong 1 captured the headwaters of the proto-Chao Phraya and became the proto-Mekong 2, while the NCSB was filled by sediment from the Malay–Thai Peninsula. This major change marks a very important drainage reorganisation in the southern SCS region.

Women, Violence, and Gender Dynamics during and after the Five Patani-Siam Wars, 1785–1838

AbstractThis article examines five wars that occurred on the Malay-Thai Peninsula in the period 1785–1838 and the deep impact they had upon women's lives during and after the conflicts. Constituting the majority of surviving refugees, women rebuilt their lives in the wake of war through business and trade in Malaya, as Islamic teachers in Mecca and Southeast Asia, and as servants and slaves in Bangkok. In each of these settings, women encountered new forms of agency and newfound challenges, shifting cultural values that regulated decisions and actions, and evolving perceptions of the qualifications for leadership. Focused upon the political demise of the Patani Sultanate, a state with a long history of female rule, this study is of particular relevance to scholarly debates concerning women in contemporary warfare because of its transnational focus with keen attention to women in a variety of Islamic spaces and contexts, its aim of dispelling the pervasive notion of Muslim women as lacking agency, and as a point of comparison for the present armed conflict still raging in Southern Thailand that has claimed more than five thousand and continues to impact women and gender dynamics in the region.

A new Holocene sea-level record for Singapore

Relative sea-level (RSL) records from far-field regions distal from ice sheets remain poorly understood, particularly in the early Holocene. Here, we extended the Holocene RSL data from Singapore by producing early Holocene sea-level index points (SLIPs) and limiting dates from a new ~40 m sediment core. We merged new and published RSL data to construct a standardized Singapore RSL database consisting of 88 SLIPs and limiting data. In the early Holocene, RSL rose rapidly from −21.0 to −0.7 m from ~9500 to 7000 cal. yrs. BP. Thereafter, the rate of RSL rise decelerated, reaching a mid-Holocene highstand of 4.0 ± 4.5 m at 5100 cal. yrs. BP, before falling to its present level. There is no evidence of any inflections in RSL when the full uncertainty of SLIPs is considered. When combined with other standardized data from the Malay-Thai Peninsula, our results also show substantial misfits between regional RSL reconstructions and glacial isostatic adjustment (GIA) model predictions in the rate of early Holocene RSL rise, the timing of the mid-Holocene highstand and the nature of late-Holocene RSL fall towards the present. It is presently unknown whether these misfits are caused by regional processes, such as subsidence of the continental shelf, or inaccurate parameters used in the GIA model.

Genetic diversity of the tire track eel Mastacembelus favus in Southeast Asia inferred from microsatellite markers

The tire track eel, Mastacembelus favus, is an economically important freshwater fish in mainland Southeast Asia. Understanding the spatial population structure is important to design an effective and efficient management of the species. The aim of this study was to investigate the genetic diversity and structure of M. favus populations. In total, 519 individuals from 30 locations across its distribution range were genotyped using a set of eight polymorphic microsatellite loci. Results showed that populations in Mekong and Chao Phraya exhibited higher genetic variability than those from Gulf of Thailand and Malay–Thai Peninsula. Clustering results revealed two evolutionarily isolated groups geographically separated at Northeastern Cambodia; the more widespread group was further divided into two subclusters. The spatial genetic variation and structure of its populations are attributed to the evolutionary history and population dynamics of the species. The study provides important information for the management and conservation of M. favus in Southeast Asia.

Genetic variation, demographic history and phylogeography of tire track eel, Mastacembelus favus (Synbranchiformes: Mastacembelidae) in Southeast Asia

The complex climatic and geological history of Southeast Asia has been hypothesised to determine the most important aspects of the current phylogeographical structure and distribution of living organisms throughout the region. To test existing hypotheses, the genetic structure of the tire track eel, Mastacembelus favus, was investigated using 823 bp of mitochondrial DNA cytochrome b from 469 individuals from 51 localities encompassing its native range. The results classified all haplotypes into two major lineages, Lineage 1, which was further divided into Lineages 1a (lower Mekong, eastern Gulf of Thailand and Malay—Thai Peninsula), 1b (Banpakong River), 1c (Chao Phraya, Gulf of Thailand and Malay—Thai Peninsula) and 1d (Khlang Yai River), and Lineage 2, the upper reaches of the lower Mekong and the middle Mekong. Strong genetic discontinuities dated approximately 5 MYA were discovered in the Mekong with limited geographical overlap, suggesting a historically dissected drainage between two sections and species colonisation via different routes. The widespread Lineage 1 showed a strong signature of population expansion during the Pleistocene climate oscillation. Haplotype characteristics in the Malay—Thai Peninsula are hypothesised to result from postglacial dispersal from the Mekong and Chao Phraya through an extended Pleistocene drainage network.

Forest surveys extend the range of the Krau woolly bat (Kerivoula krauensis) in the Malay-Thai Peninsula, Borneo and Sumatra

Abstract Kerivoula krauensis was formally described in 2007 and until recently was only known from tropical forest in central peninsular Malaysia. We report four new records, which, together with recent published collections, extend the known range for this species to peatswamps, lowland and montane forests in Borneo and Sumatra (Brunei and Indonesia), and further north on the Malay peninsula, including Thailand. External body measurements and cranial data match well with those from the type locality, although echolocation call parameters differ – most likely due to technological improvements in recording devices. The species remains patchily distributed and rarely encountered, despite substantial sampling effort.

Holocene coastal response to monsoons and relative sea-level changes in northeast peninsular Malaysia

Sedimentological, geomorphic, and ground penetrating radar (GPR) data are combined with optically stimulated luminescence data to define the Holocene evolution of a coastal system in peninsular Malaysia. The Setiu coastal region of northeast Malaysia comprises five geological and geomorphic units representing distinct evolutionary phases of this coastline. Estimated marine limiting point elevations indicate deposition of an early aggradational shoreline associated with a sea-level elevation of −0.1 to +1.7m (MSLPMVGD datum) between ∼6.8ka and 5.7ka, in agreement with previous sea-level studies from the Malay–Thai peninsula. A hiatus occurs in the record between ∼5.7ka and 3.0ka, possibly due to a relative sea-level oscillation and shoreline erosion. Long-term relative sea-level fall and possible still-stands created strandplains that are interrupted by aggradational to transgressive paleo-barrier and estuary formation corresponding with brief episodes of RSL rise. Analyses of GPR facies and OSL ages suggest annual clinoform deposition, with geometries dictated by variations in ENSO. These data demonstrate the utility of high resolution studies of coastal facies as useful proxy indicators for paleoclimate studies at subdecadal to millennial time-scales.

Diversity of Malaysian insectivorous bat assemblages revisited

Abstract:To what extent tropical forest persisted in the Malay-Thai Peninsula during the Last Glacial Maximum, or contracted southwards with subsequent post-glacial expansion, has long been debated. These competing scenarios might be expected to have left contrasting broad spatial patterns of diversity of forest-dependent taxa. To test for a post-glacial northward spread of forest, we examined latitudinal clines of forest-dependent bat species at 15 forest sites across Peninsular Malaysia. From captures of 3776 insectivorous forest bats, we found that low richness characterized the north of the study area: predicted richness of 9–16 species, compared with 21–23 in the south. Predicted species richness decreased significantly with increasing latitude, but showed no relationship with either seasonality or peninsula width. Analyses of beta-diversity showed that differences between communities were not related to geographical distance, although there was evidence of greater differences in species numbers between the most distant sites. Assemblages were consistently dominated by six cave-roosting species from the families Rhinolophidae and Hipposideridae, while another 16 species were consistently rare. We suggest that these observed patterns are consistent with the hypothesized northward expansion of tropical rain forest since the Last Glacial Maximum, but emphasize that more surveys in the extreme north and south of the peninsula are required to support this assertion.

Holocene sea levels along the Andaman Sea coast of Thailand

For the Malay-Thai Peninsula several sea-level curves for the younger Holocene, based on field evidence as well as on hydro-isostatic modelling of a far-field site, have been published. The general assumption is a rapid rise to a mid-Holocene maximum up to +5 m above present sea level, followed by a constant or oscillating regression. However, from the Andaman Sea coast of Thailand, which was affected by the 2004 tsunami, only isolated observations are available regarding Holocene sea levels. Thus, the timing and magnitude of the Holocene highstand as well as the course of the regression remain to be defined. As several palaeotsunamis could be detected in the meantime it is important to know the related sea levels as exactly as possible to judge the energy, inundation width and potential wave height of these events. Therefore, fixed biological indicators from the rocky coasts of the Phang-nga Bay and Phuket, as well as morphological indicators from beach-ridge and swale sequences along the exposed west coast (Ko Phra Thong) were studied, to gain information about the Holocene sea-level development in this region. While oyster and coral data from the Phang-nga Bay and Phuket document a Holocene maximum of +2.6 m at 5700 cal. BP, the ridge crests and swale bases in the northwest of the study area point to maximum heights of +1.5–2.0 m above the present level around 5300 years ago. During the last 3000 years, to when the largest part of the Holocene palaeotsunami deposits from Thailand was dated, relative sea levels (RSL) in both areas did not exceed +1.5 m.

The role of desiccation tolerance in determining tree species distributions along the Malay–Thai Peninsula

1 Patterns of water availability are frequently implicated in local and regional tree species distributions. A major floristic and climatic transition from aseasonal to seasonal evergreen tropical forest is the Kangar–Pattani Line (KPL) in the Indo-Sundaic region of Southeast Asia. We hypothesize that differences in species’ drought tolerance will correspond with their distribution with respect to the KPL. Using a common garden study, we assess the role of differences in physiological drought tolerance traits to geographic distributions for 24 tropical tree species in relation to rainfall seasonality. 2 Inherent differences in desiccation tolerance of seedlings were quantified as water potentials and relative water contents (RWCs) below which the plant could no longer support living tissue, and plant water relation parameters were measured using pressure–volume analysis. The relationships among these traits were examined using bivariate trait relationships and a principal components analysis (PCA). The physiological traits contributing most to lethal water potential and RWC were assessed using multiple regression analysis. 3 Distribution-related differences in all desiccation tolerance and pressure–volume traits were detected both with and without phylogenetic correction. Widespread species that occurred in seasonally dry forests were able to maintain living tissue at more negative water potentials and lower RWCs than were species restricted to aseasonal forests. Likewise, widespread species demonstrated more negative water potentials at turgor loss, more negative saturated osmotic potential, lower symplastic water fraction and higher bulk modulus of elasticity values. Turgor loss point (TLP) and bulk modulus of elasticity were the best predictors of lethal water potential while symplastic water fraction and bulk modulus of elasticity were included as predictors of lethal RWC. 4 Inherent differences in physiological traits contributing to drought tolerance are associated with differences in tropical tree species distributions in relation to rainfall seasonality. These results, combined with lack of support for hypothesized historical factors, strongly implicate climate as a determinant of tree species distributions around the KPL.

Indian Ocean tsunami deposits along the West Coast of the Malay-Thai Peninsula: foraminiferal and grain size analysis

Abstract

Holocene sea levels and palaeoenvironments, Malay-Thai Peninsula, southeast Asia

Sedimentological and palynological investigations of Great Songkhla Lakes, east coast of the Malay-Thai Peninsula, Southeast Asia, reveal sedimentary sequences rich in palynomorph assemblages dominated by pollen of mangroves and freshwater swamps. Compared with other regions in Southeast Asia the assemblages are of relatively low diversity. Geochronological data indicate that the Great Songkhla Lakes record one of the earliest mangrove environments in Southeast Asia (8420-8190 cal. yr BP), which are subsequently replaced by a freshwater swamp at 7880-7680 cal. yr BP owing to the decline of marine influence. Sea-level observations from Great Songkhla Lakes and other areas of the Malay-Thai Peninsula reveal an upward trend of Holocene relative sea level from a minimum of -22 m at 9700-9250 cal. yr BP to a mid-Holocene high stand of 4850-4450 cal. yr BP, which equates to a rise of c. 5.5 mm/yr. The sea-level fall from the high stand is steady at c. - 1.1 mm/yr. Geophysical modelling shows that hydroisostasy contributes a significant spatial variation to the sea-level signal between some site locations (3-4 m during the mid-Holocene), indicating that it is not correct to construct a single relative sea-level history for the Malay-Thai Peninsula.

Sea-level changes in the tectonically stable Malay-Thai Peninsula

Abstract The Malay-Thai Peninsula is part of Sundaland, a geological region of relative crustal stability. Therefore, the positions of old shorelines (of the past 20,000 years or so) can be considered to indicate positions of actual past sea levels. Over 200 shoreline indicators at positions below as well as above present sea level have been radiocarbon dated. These dated positions indicate that prior to 6 ka the sea rose from at least 90 m below present sea level at rates that initially amounted to 15 mm/year and later became 6 mm/year. At ca. 6 ka, the rising sea surpassed its current position and at ca. 5 ka, it reached 5 m. During this maximum marine inundation, the peninsula was narrower, since the low coastal plains did not yet exist. In the period following this maximum transgression, the available shoreline data indicate that regional sea level subsided through a series of fluctuations that were characterized by amplitudes of 2 m and periods of about 2000 years. The peaks and troughs of the fluctuations became progressively lower. The latest peak was at about +1.7 m (or 0.7 m above present high tide) a few hundred years ago. The cause of these fluctuations is not yet known, but the trend suggests that, in the near future, regional sea level may subside at annual rates between 1.5 mm and 2 mm. This rate of descent is 25 to 30% of the estimated rate of sea-level rise that may result from global warming. In other words, for the Malay-Thai Peninsula, the effect of sea-level rise on account of manmade greenhouse gases will be partly compensated by actual subsidence of regional sea level.

Holocene sea-level changes in the Malay-Thai Peninsula, a tectonically stable environment

The Malay-Thai Peninsula is part of tectonically stable Sundaland, which is the southeast corner of the Eurasian Plate. The Holocene sea-level changes in the region are deduced from a total of 200 dated shoreline indicators. Sea level reached a peak of about 5 m and about 4 m some 5,000 years and 6,000 years ago in Peninsular Malaysia and Thailand. This mid-Holocene transgression was followed by sea-level decrease that took place either gradually, or step-wise with thousand-year periods of stillstand, or more likely in a series of short to medium long periods of regressions and smaller transgressions. During one of the regressions, Late Holocene sea level probably dropped below current datum. Shoreline indicators of pre Mid-Holocene age located between the latitudes of the Langkawi Islands and Phang Nga are anomalously high. These high elevations suggest geoidal relief of up to 40 metres between the northern and southern parts of Strait Malacca.

Some thoughts on the development of the alluvial tinfields of the Malay-Thai Peninsula

Some thoughts on the development of the alluvial tinfields of the Malay-Thai Peninsula

Cretaceous-Tertiary Events in Southeast Asia

Research Article| April 01, 1969 Cretaceous-Tertiary Events in Southeast Asia C. K BURTON; C. K BURTON Geology Department, Faculty of Science, Chulalongkorn University, Bangkok, Thailand Department of Geology and Mineralogy, University of Oxford, Parks Road, Oxford, England and (presently) Search for other works by this author on: GSW Google Scholar J. D BIGNELL J. D BIGNELL Department of Geology, University of Malaya, Kuala Lumpur, West Malaysia Search for other works by this author on: GSW Google Scholar Author and Article Information C. K BURTON Geology Department, Faculty of Science, Chulalongkorn University, Bangkok, Thailand Department of Geology and Mineralogy, University of Oxford, Parks Road, Oxford, England and (presently) J. D BIGNELL Department of Geology, University of Malaya, Kuala Lumpur, West Malaysia Publisher: Geological Society of America Received: 01 Jul 1968 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1969, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1969) 80 (4): 681–688. https://doi.org/10.1130/0016-7606(1969)80[681:CEISA]2.0.CO;2 Article history Received: 01 Jul 1968 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. K BURTON, J. D BIGNELL; Cretaceous-Tertiary Events in Southeast Asia. GSA Bulletin 1969;; 80 (4): 681–688. doi: https://doi.org/10.1130/0016-7606(1969)80[681:CEISA]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Recorded field evidence and new isotopic data from Thailand both show that the granites northeast of the Gulf of Thailand are mainly Triassic or older. Published and unpublished radiometric investigations on granites from the Malay-Thai peninsula reveal widespread Cretaceous to Tertiary activity, including some granite emplacement, which is possibly related to epeirogenic movements. These interpretations differ significantly from those of Hilde and Engel (1967), who report a zone of Late Cretaceous granites along the northeastern coast of the Gulf of Thailand. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.