Phanerozoic Volcanism of Southwest Uganda: A Case for Regional K and Lile Enrichment of the Lithosphere Beneath a Domed and Rifted Continental Plate

1991 ◽  
pp. 23-72 ◽  
Author(s):  
F. E. Lloyd ◽  
A. T. Huntingdon ◽  
G. R. Davies ◽  
P. H. Nixon
Keyword(s):  
Continental Plate

scholarly journals The fluid budget of a continental plate boundary fault: Quantification from the Alpine Fault, New Zealand

2016 ◽  
Vol 445 ◽  
pp. 125-135 ◽  
Author(s):  
Catriona D. Menzies ◽  
Damon A.H. Teagle ◽  
Samuel Niedermann ◽  
Simon C. Cox ◽  
Dave Craw ◽  
...  
Keyword(s):  
New Zealand ◽  
Plate Boundary ◽  
Boundary Fault ◽  
Continental Plate ◽  
Alpine Fault

Late Cretaceous granitoids of the Sikhote–Alin orogenic belt, southeastern Russia: implications for the Mesozoic geodynamic history of the eastern Asian continental margin

2021 ◽  
pp. jgs2021-109
Author(s):  
Igor V. Kemkin ◽  
Andrei V. Grebennikov ◽  
Xing-Hua Ma ◽  
Ke-Ke Sun
Keyword(s):  
Late Cretaceous ◽  
Pacific Plate ◽  
Orogenic Belt ◽  
Sikhote Alin ◽  
Asian Continent ◽  
Content Type ◽  
Eastern Margin ◽  
Continental Plate ◽  
Supplementary Material ◽  
Cretaceous Magmatism

We present new U–Pb age data for granitoids in the Central Sikhote–Alin orogenic belt in SE Russia, which refute the established opinion about the absence of the Late Cretaceous magmatism at the eastern margin of the Paleo-Asian continent. It was previously thought that a period of magmatic quiescence occurred from 88 to 50 Ma, related to subduction of the Paleo-Pacific Plate under the eastern margin of the Paleo-Asian continent, although this is inconsistent with evidence from the Sikhote–Alin, Sakhalin, and Japan regions. Three suites of plutonic rocks with different ages were identified in this study. The first suite has ages of 105–92 Ma and formed in a syn-orogenic setting. The second (86–83 Ma) and third (ca. 73 Ma) suites formed during the post-orogenic stage of the Sikhote–Alin orogenic belt. The second and third suites were coeval with Late Cretaceous granitoids that formed in a suprasubduction continental arc known as the Eastern Sikhote–Alin volcanic–plutonic belt (ESAVPB). However, the studied rocks are located far inland from the ESAVPB. The ages of the studied granitoids coincide with the timing of a change in the angle of convergence between the Paleo-Pacific Plate and eastern margin of the Paleo-Asian continent. This change in motion of the oceanic plate with respect to the continental plate was probably caused by a rupture in the subducted slab (i.e., a slab tear), followed by asthenospheric upwelling and partial melting of the overlying crust, which ultimately generated post-orogenic intrusive magmatism.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5738616

PERBANDINGAN SIMPANGAN GEDUNG LANTAI RENDAH DENGAN MENGGUNAKAN 2 TIPE BRESING

EXTRAPOLASI ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 35-44
Author(s):  
Nurul Rochmah
Keyword(s):  
Pacific Ocean ◽  
Steel Structure ◽  
Steel Structures ◽  
Oceanic Plate ◽  
Lateral Loads ◽  
Continental Plate ◽  
Eurasian Continent ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Eccentric Bracing

AbstractIndonesia is one of the areas where earthquakes often occur, one reason is that Indonesia is located on the border of the oceanic plate, namely the pacific ocean and the continental plate, namely the Eurasian continent. Where in these areas plate shifts often occur which cause frequent earthquakes.In minimizing casualties due to building failure due to earthquakes, one of them is necessary to make a building that has sufficient ductility so that in this study using a steel structure building.In steel structures, to make the structure more resistant to lateral loads, it is necessary to apply bracing. In this study, we try to compare the eccentric and concentric bracing displacement in steel structure buildings.Based on the results obtained from the comparison of these displacements, it is found those displacements due to eccentric bracing is smaller than the concentric bracing  AbstrakIndonesia termasuk daerah yang sering terjadi gempa, salah sebabnya karena wilayah Indonesia terletak di daerah perbatasan lempeng samudera yaitu samudera pasisfik dan lempeng benua yaitu benua Eurasia. Dimana di daerah tersebut sering terjadi pergeseran lempeng yang menyebabkan sering terjadi gempa.Dalam meminimalisir korban akibat kegagalan bangunan akibat gempa salah satunya perlu membuat suatu bangunan yang mempunyai daktilitas yang cukup sehingga dalam penelitian ini memakai gedung struktur baja.Pada Struktur baja untuk lebih membuat struktur bisa tahan terhadap beban lateral maka perlu diberi bresing. Dalam penelitian ini mencoba untuk membandingkan simpangan bresing eksentrik dan konsentrik pada gedung struktur baja.Berdasarkan hasil yang diperoleh dari perbandingan simpangan tersebut, maka diperoleh simpangan akibat bresing eksentrik lebih kecil di banding bresing konsentrik.

RESILIENCE OF ADOLESCENT POST-DISASTER ERUPTION OF MOUNT SEMERU: LITERATURE REVIEW

2021 ◽  
Vol 2 (2) ◽  
pp. 164
Author(s):  
Primasari Mahardhika Rahmawati ◽  
Suhari Suhari ◽  
Anggia Astuti ◽  
Musviro Musviro
Keyword(s):  
Literature Review ◽  
Continental Plate ◽  
Sources Of Support ◽  
Post Disaster ◽  
Selection Of ◽  
Youth Resilience ◽  
Active Volcanoes

Introduction:Indonesia sits on an active continental plate, surrounded by a series of very active volcanoes called the ring of fire. These conditions make Indonesia very vulnerable to disasters. Mount Semeru was observed to have experienced at least 57 eruptions or eruptions. The resilience possessed by adolescents can affect when the post-eruption disaster strikes.Methods:The strategy to determine the selection of studies that have been found, the author uses a protocol and evaluation uses the PRISMA Checklist and is adjusted to the purpose of this literature review. Searching for literature sources in this literature review uses several databases including PubMed and Google ScholarResults:Resilience is very important for adolescents in post-mountain eruption disaster situations, adolescents who have resilience can survive and never give up in difficult circumstances, adapt to these conditions, and can rise. Most of the adolescents in post-disaster areas have moderate levels of resilience as much as 64% and as high as 63%. This can occur due to several factors, namely individuals, families, and communities. In addition, gender can also affect a person's resilience. Men are more resilient than women.Conclusion:The existence of sources of support from internal and external as well as knowledge about adolescent disasters can optimize youth resilience after the Semeru eruption disaster.

Volcanic Hazards in Southeast Asia

2005 ◽  
Author(s):  
Jan J. Nossin
Keyword(s):  
Southeast Asia ◽  
Natural Hazards ◽  
Underlying Mechanism ◽  
Volcanic Hazards ◽  
The Philippines ◽  
Tectonic Plates ◽  
Continental Plate ◽  
Historical Times ◽  
Oceanic Plates ◽  
Definition Of

Active volcanism in Southeast Asia is associated with marked zones of activity in the Earth’s crust that run through south and east Indonesia and the Philippines. These zones are also characterized by frequent earthquakes and a measurable movement of tectonic plates, often in the order of 5 cm yr−1. The underlying mechanism is that of subduction of oceanic plates below continental plates; the rigidity of the moving plates causes ruptures and shockwise adjustments (earthquakes). The oceanic plate, while being under thrust, sinks down to great depths below the continental plate and in the process loses its rigidity owing to heating and part assimilation into the underlying magma. Earthquakes are caused in the zone where the subducted plate is still rigid. Chapter 1 in this book puts this phenomenon in the regional context. Volcanism in this zone is marked by frequent eruptions, mostly violent and of an explosive nature. It is manifest in distinct belts that comprise all (or nearly all) of the Philippines, and large parts of Indonesia with the exception of, roughly speaking, Kalimantan and Papua. The violence of the eruptions poses threats to human settlements in the surroundings of the volcanoes, to the cultivated lands, and the infrastructure. These threats may occur during and after the actual eruption, and they may indirectly cause other hazards as well. Moreover, volcanoes in apparent dormancy that have not erupted in historical times may still come to life as the interval between eruptions may be very long. In the present chapter these hazards will be discussed. Natural hazards have been defined in four ways, of which the 1982 definition of the United Nations Disaster Relief Co-ordinator (UNDRO) seems appropriate to follow in the context of volcanic hazards (Alexander 1993). UNDRO defines natural hazards as ‘the probability of occurrence within a specific period of time and within a given area of a potentially damaging phenomenon’. A hazard therefore may represent a situation with the possibility of a disaster that may affect the population and the environment which are in some degree of vulnerability.

scholarly journals Redox state of southern Tibetan upper mantle and ultrapotassic magmas

Geology ◽  
2020 ◽  
Vol 48 (7) ◽  
pp. 733-736 ◽  
Author(s):  
Weikai Li ◽  
Zhiming Yang ◽  
Massimo Chiaradia ◽  
Yong Lai ◽  
Chao Yu ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Redox State ◽  
Volcanic Rocks ◽  
Mantle Xenoliths ◽  
Continental Plate ◽  
Cratonic Mantle ◽  
Tectonic Settings ◽  
Mantle Condition ◽  
Typical Range

Abstract The redox state of Earth’s upper mantle in several tectonic settings, such as cratonic mantle, oceanic mantle, and mantle wedges beneath magmatic arcs, has been well documented. In contrast, oxygen fugacity () data of upper mantle under orogens worldwide are rare, and the mechanism responsible for the mantle condition under orogens is not well constrained. In this study, we investigated the of mantle xenoliths derived from the southern Tibetan lithospheric mantle beneath the Himalayan orogen, and that of postcollisional ultrapotassic volcanic rocks hosting the xenoliths. The of mantle xenoliths ranges from ΔFMQ = +0.5 to +1.2 (where ΔFMQ is the deviation of log from the fayalite-magnetite-quartz buffer), indicating that the southern Tibetan lithospheric mantle is more oxidized than cratonic and oceanic mantle, and it falls within the typical range of mantle wedge values. Mineralogical evidence suggests that water-rich fluids and sediment melts liberated from both the subducting Neo-Tethyan oceanic slab and perhaps the Indian continental plate could have oxidized the southern Tibetan lithospheric mantle. The conditions of ultrapotassic magmas show a shift toward more oxidized conditions during ascent (from ΔFMQ = +0.8 to +3.0). Crustal evolution processes (e.g., fractionation) could influence magmatic , and thus the redox state of mantle-derived magma may not simply represent its mantle source.

Magnetotelluric imaging of a fossil oceanic plate in northwestern Xinjiang, China

Geology ◽  
2020 ◽  
Vol 48 (4) ◽  
pp. 385-389 ◽  
Author(s):  
Y.X. Xu ◽  
B. Yang ◽  
A.Q. Zhang ◽  
S.C. Wu ◽  
L. Zhu ◽  
...  
Keyword(s):  
Subcontinental Lithospheric Mantle ◽  
Oceanic Plate ◽  
Continental Lithosphere ◽  
Magnetotelluric Data ◽  
Long Period ◽  
Continental Plate ◽  
Formation And Evolution ◽  
Magnetotelluric Imaging ◽  
Plate Subduction ◽  
Continental Accretion

Abstract Because an oceanic plate colliding with a continental plate will usually be subducted and recycled into the deep mantle, a fossil oceanic plate after the closure of an ancient ocean has rarely been imaged in the subcontinental lithospheric mantle. This has led to a long-standing debate about the fate of subducted ocean plates. The problem can be addressed by imaging the lithosphere in a continental accretion zone with past ocean subduction. We present a study using long-period magnetotelluric data that reveals a large shallow-mantle conductor in a Phanerozoic accretion area in northwestern Xinjiang, China. This conductor extends >300 km laterally at depths from 120 to 220 km and resembles a segment of a fossil oceanic plate. The reduced resistivity is ascribed to the volatile-bearing metasomatic minerals, based on its relatively fertile nature and low temperature. Our results demonstrate that an oceanic plate can be trapped in continental lithosphere, underscoring the significance of oceanic plate subduction to continental accretion, and shedding new light on our understanding of continental formation and evolution.

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