Preliminary geochemical and age data from postsubduction intrusive rocks, northwest Borneo

Williams, Paul R.; Harahap, Bhakti H.

doi:10.1080/08120098708729422

Cited by 33 publications

(13 citation statements)

References 12 publications

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“…ages, from either hornblende or biotite, vary between approximately 30 and 16 m.y. (Upper Oligocene and Lower Miocene)(Kirk [1968],Williams and Harahap [ 1987], and this study). The origin of the intrusions is problematic because the K-Ar ages postdate the presumed end of subduction in the area[Williams and Hamhap, 1987].…”

mentioning

confidence: 73%

Paleomagnetic data from Sarawak, Malaysian Borneo, and the Late Mesozoic and Cenozoic tectonics of Sundaland

Schmidtke¹,

Fuller²,

Haston³

1990

Tectonics

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Paleomagnetic data from 231 samples from 31 sites in rocks of Upper Jurassic to Miocene age in Sarawak (Malaysian Borneo) reveal a trend of increasing counterclockwise (CCW) declination deflection with age. Six sites in Tertiary hypabyssal intrusions show 8° to 52° of CCW deflection. The intrusion deflected 52° CCW was K‐Ar dated at 26 m.y. (Upper Oligocene), while one deflected 22° CCW gives a 17 m. y. age (Lower Miocene). Three sites in the Upper Eocene to Miocene(?) Silantek Formation show an average 40° of CCW deflection. Prefolding directions, showing 90° of CCW deflection, are isolated in 4 sites (including two positive fold tests) in Upper Jurassic and Cretaceous rocks of the Bau Limestone and Pedawan Formations. A postfolding, Cenozoic remagnetization with an average of 60° of CCW deflection is found in five Bau Limestone sites. Three sites in the Upper Jurassic Kedadom Formation show an average of 50° of CCW deflection. CCW declination deflections found in Mesozoic and Cenozoic rocks as far as 400 km east and 150 km south of Sarawak, in Kalimantan (Indonesian Borneo), also fit the trend of deflection versus age. On the basis of the regional consistency of declination deflection versus age, along with geologic evidence the data are considered to be evidence of a regional (rather than a local block or distributed shear) rotation. The domain of CCW rotation extends into West Malaysia, suggesting that West Borneo and the Malay Peninsula may have been a stable block during the latest Cretaceous and Cenozoic. West Malaysia and Borneo may have had different histories in the rest of the Mesozoic. The data imply up to 108° CCW rotation of Borneo with respect to stable Eurasia, sometime during the Cretaceous and Cenozoic. Cenozoic rotation may also have occurred between Indochina and Borneo. The sense of rotation shown by the data does not support the “propagating extrusion tectonics” model for Cenozoic Southeast Asia.

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confidence: 73%

Paleomagnetic data from Sarawak, Malaysian Borneo, and the Late Mesozoic and Cenozoic tectonics of Sundaland

Schmidtke¹,

Fuller²,

Haston³

1990

Tectonics

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“…Upper Cretaceous‐Upper Eocene basins and younger basins unconformably cover the Paleozoic‐Mesozoic rocks of the Kuching Zone (Williams et al, , ). Locally, these are intruded by small‐scale Oligocene‐Miocene stocks (Fuller et al, ; Williams & Harahap, ).…”

Section: Geologic Settingmentioning

confidence: 99%

Cenozoic Rotation History of Borneo and Sundaland, SE Asia Revealed by Paleomagnetism, Seismic Tomography, and Kinematic Reconstruction

Advokaat

Marshall

et al. 2018

Tectonics

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SE Asia comprises a heterogeneous assemblage of fragments derived from Cathaysia (Eurasia) in the north and Gondwana in the south, separated by suture zones representing closed former ocean basins. The western part of the region comprises Sundaland, which was formed by Late Permian‐Triassic amalgamation of continental and arc fragments now found in Indochina, the Thai Penisula, Peninsular Malaysia, and Sumatra. On Borneo, the Kuching Zone formed the eastern margin of Sundaland since the Triassic. To the SE of the Kuching Zone, the Gondwana‐derived continental fragments of SW Borneo and East Kalimantan accreted in the Cretaceous. South China‐derived fragments accreted to north of the Kuching Zone in the Miocene. Deciphering this complex geodynamic history of SE Asia requires restoration of its deformation history, but quantitative constraints are often sparse. Paleomagnetism may provide such constraints. Previous paleomagnetic studies demonstrated that Sundaland and fragments in Borneo underwent vertical axis rotations since the Cretaceous. We provide new paleomagnetic data from Eocene‐Miocene sedimentary rocks in the Kutai Basin, east Borneo, and critically reevaluate the published database, omitting sites that do not pass widely used, up‐to‐date reliability criteria. We use the resulting database to develop an updated kinematic restoration. We test the regional or local nature of paleomagnetic rotations against fits between the restored orientation of the Sunda Trench and seismic tomography images of the associated slabs. Paleomagnetic data and mantle tomography of the Sunda slab indicate that Sundaland did not experience significant vertical axis rotations since the Late Jurassic. Paleomagnetic data show that Borneo underwent a ~35° counterclockwise rotation constrained to the Late Eocene and an additional ~10° counterclockwise rotation since the Early Miocene. How this rotation was accommodated relative to Sundaland is enigmatic but likely involved distributed extension in the West Java Sea between Borneo and Sumatra. This Late Eocene‐Early Oligocene rotation is contemporaneous with and may have been driven by a marked change in motion of Australia relative to Eurasia, from eastward to northward, which also has led to the initiation of subduction along the eastern Sunda trench and the proto‐South China Sea to the south and north of Borneo, respectively.

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“…Plate boundaries, marginal ocean basins and arc systems (Fuller et al, 1999;Nagarajan et al, 2014) surround this region. This region has experienced significant tectonic activity (Hall, 2013), Cretaceous magmatism (Williams et al, 1988;Davies et al, 2014;Hennig et al, 2017), and volcanism during the Cretaceous (van Gorsel, 2012) to the Miocene (Williams and Harahap, 1987;Prouteau et al, 2001). Previous studies have correlated the tectonic activity with two main deformations namely, the NE-SW to NW-SE trending syn-depositional growth faulting during the Cretaceous-Eocene, superposed by the Late Miocene to the Pliocene NE-SW trending wrenchinduced compressional folds (Shuib, 2003).…”

Section: Regional Settingmentioning

confidence: 99%

“…There have been alternative interpretations as well: During the Eocene and the Oligocene, from Sumatra to Sulawesi, abundant volcanic activity accompanied northward subduction of the Indian-Australian Plate. The Cenozoic magmatism has been considered a complex event with diverse opinions on the timing and origin of the event (Williams and Harahap, 1987;Prouteau et al, 2001;Cullen et al, 2013). During the Late Cretaceous-Early Eocene, rifting at the margin of Asia to produce the South China Sea took place, resulting in a southward movement of the Luconia continental block that led to the conception of a magmatic belt due to the southward subduction.…”

Section: Fig 13mentioning

confidence: 99%

Late Middle Miocene volcanism in Northwest Borneo, Southeast Asia: Implications for tectonics, paleoclimate and stratigraphic marker

Ramkumar

Santosh

Nagarajan

et al. 2018

Palaeogeography, Palaeoclimatology, Palaeoecology

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Explosive volcanic events often produce pyroclastic materials that can be recognized from the geological record. These discrete pyroclastics form regional marker beds. Here we report the occurrence of a tephra layer interbedded within very thick coal beds near Mukah, Sarawak, Borneo. Traceable for tens of kilometers in the Mukah area of Sarawak, this tephra layer can be considered as regional stratigraphic marker with precise chronostratigraphic control. Systematic sedimentological, mineralogical, geochemical and zircon U-Pb geochronological studies have revealed a major effusive volcanic event during the latest Middle Miocene, presumably contemporaneous and/or related to a magmatic event of an earlier phase of the Mt. Kinabalu pluton or magmatism in West Sarawak or East Sabah. The volcanic event had promoted catastrophic flooding of coastal swamps and fallout from the ash clouds that formed a regionally monotonous tephra layer across the Serravallian-Tortonian boundary. In conjunction with the regional occurrences of trap rocks, structural trends and known tectonic events, we constrained the regional depositional environments, and climate. The tephra layer was deposited in a coastal plain-swamp,seasonal, shallow, high-moderate energy fluvial channel-lacustrine environmental setting, wherein atmospheric fallout and eroded material from regoliths formed over older basement and volcanic rocks of the hinterland which were mixed to produce the tephra layer. This tephra layer is sandwiched between the very thick coal beds. A pre-existent volcanic chamber that was active for a long time, also experienced periodic explosive activity from probably the same magma chamber and conduit and including a major explosive activity that recycled early-formed crystals and felsic magma (rhyolite-dacite) during the major effusive event are also recognized. Our findings provide robust evidence for the prevalence of intensive chemical weathering under a wet-humid climate, and relative tectonic quiescence before the major effusive event, and the existence of vast, monotonously gently-sloping coastal plains and luxuriant vegetation akin to the present.

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Preliminary geochemical and age data from postsubduction intrusive rocks, northwest Borneo

Cited by 33 publications

References 12 publications

Paleomagnetic data from Sarawak, Malaysian Borneo, and the Late Mesozoic and Cenozoic tectonics of Sundaland

Paleomagnetic data from Sarawak, Malaysian Borneo, and the Late Mesozoic and Cenozoic tectonics of Sundaland

Cenozoic Rotation History of Borneo and Sundaland, SE Asia Revealed by Paleomagnetism, Seismic Tomography, and Kinematic Reconstruction

Late Middle Miocene volcanism in Northwest Borneo, Southeast Asia: Implications for tectonics, paleoclimate and stratigraphic marker

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