scholarly journals On The Supposed Onshore Extension Of The Penyu Basin, Peninsular Malaysia

Warta Geologi ◽  
2021 ◽  
Vol 47 (3) ◽  
pp. 204-210
Author(s):  
Mazlan Madon ◽  

The Penyu Basin is a Tertiary sedimentary basin located offshore Peninsular Malaysia. The basin is assumed to continue westwards beneath the Pahang River delta where as much as 115 m of Quaternary sediments overlie a bedrock of pre-Tertiary granites and metamorphic rocks. No Pliocene or older sediments beneath the delta have been reported. If the Quaternary sediments are considered as part of the Cenozoic Penyu Basin, the basin’s western limit may be delineated at the foothills of the coastal plain where those sediments onlap onto pre-Tertiary rocks. Therefore, any sedimentary rock of Tertiary age that may occur to the west of that limit most probably represents a separate basin.

CATENA ◽  
2020 ◽  
Vol 193 ◽  
pp. 104619
Author(s):  
Guangming Zhao ◽  
Siyuan Ye ◽  
Lei He ◽  
Hongming Yuan ◽  
Xigui Ding ◽  
...  

Paléorient ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 93-114
Author(s):  
Philip L. Kohl ◽  
Rabadan G. Magomedov
Keyword(s):  

2019 ◽  
Vol 21 (2) ◽  
pp. 1006-1018
Author(s):  
Ana Alexandre Santos Rodrigues ◽  
Francisco Asis Aquino Bezerra Filho ◽  
Jáder Onofre de Morais ◽  
Lidrana De Souza Pinheiro

As práticas de campo proporcionam aos discentes uma proximidade com o cotidiano. A metodologia proposta no estudo sugere uma divulgação simplificada do conhecimento cientifico da Planície Litorânea de Almofala, propondo rotas de acesso didáticas para práticas de campo que auxiliem os professores das escolas de Itarema. Para a complementação teórica foram considerados como base os inventários da Geodiversidade cientifica do litoral oeste do estado do Ceará, realizados no âmbito do projeto PRONEX. Isso foi feito por pesquisadores de várias Instituições de Ensino Superior do Ceará, e a literatura clássica local. Enquanto resultados discutidos, considerou-se que estes roteiros de práticas de campo podem ser estabelecidos e decididos em conjunto, entre professores e alunos. Tendo como base o mapa interpretativo dos roteiros, com intuito de realizar o reconhecimento e entendimento da dinâmica costeira.Palavras-chave: Educação; Geodiversidade; Planície Litorânea. ABSTRACTField practices provide students with a closeness to daily life. The methodology proposed in the study suggests a simplified dissemination of scientific knowledge of the Almofala Coastal Plain, proposing didactic access routes for field practices that help teachers of Itarema schools. For theoretical complementation, the inventories of the scientific geodiversity of the west coast of the state of Ceará, carried out under the PRONEX project were considered. It was done by researchers from various Higher Education Institutions in Ceará, and its local classical literature. As results discussed, it was considered that these field practice roadmaps can be jointly established and decided between teachers and students. Based on the interpretative map of the roadmaps, in order to recognize and understand the coastal dynamics.Keywords: Education; Geodiversity; Coastal plain. RESUMENLas prácticas de campo ofrecen a los estudiantes una cercanía a la vida diaria. La metodología propuesta en el estudio sugiere una divulgación simplificada del conocimiento científico sobre la llanura costera de Almofala, proponiendo rutas de acceso didáctico para prácticas de campo que ayudan a los docentes de las escuelas de Itarema. Para la complementación teórica fueron considerados como información base los inventarios de la geodiversidad científica de la costa oeste del estado de Ceará, realizados en el ámbito del proyecto PRONEX. Fue realizado por investigadores de varias instituciones de educación superior en Ceará, y la literatura clásica local. En cuanto a los resultados discutidos, se consideró que estas hojas de ruta de prácticas de campo pueden ser establecidas y escogidas conjuntamente entre docentes y estudiantes, con base en el mapa interpretativo de ruta, con el fin de reconocer y comprender la dinámica costera de esta región.Palabras clave: Educación; Geodiversidad; Llanura costera.


1977 ◽  
Vol 8 ◽  
pp. 45-49
Author(s):  
Richard J. Hodgkinson ◽  
Christopher D. Walley

Carbonate and clastic sediments of Jurassic and Cretaceous age are exposed along the fault-scarp of Djebel Nefusa in north-western Libya. Previous geological investigations have been mainly restricted to the eastern sector of the scarp. Recent studies by the authors in the western sector of Djebel Nefusa and on equivalent sediments in southern Tunisia have allowed the first regional interpretation of these rocks.The area studied lies geographically and geologically at the edge of the Saharan Platform, a large cratonic block, composed of rocks of Precambrian-Palaeozoic age. To the north and east lies a downfaulted sedimentary basin (Gabes-Sabratha Basin) containing a large thickness of Mesozoic sediments. The location of the sections measured along Djebel Nefusa are depicted in Fig.1.The stratigraphic nomenclature of the rock succession of Djebel Nefusa was first established in the east and continued laterally towards the west by later workers. Difficulties in the application of this nomenclature are presented by the recognition of facies changes previously overlooked by earlier investigators. However, as a framework for understanding these changes and the sedimentary processes which caused them, the stratigraphy erected by Magnier (1963) is adopted.


Author(s):  
Yuriy V. Erokhin ◽  
Kirill S. Ivanov ◽  
Anatoliy V. Zakharov ◽  
Vera V. Khiller

The results of studying the mineralogy of metamorphic schists from the Pre-Jurassic base of the Arctic part of the West Siberian plate are presented. The accessory and ore mineralization of schists from the Zapadno-Yarotinsky license area located in the southern part of the Yamal Peninsula is studied. The schists was uncovered by the Zapadno-Yarotinskaya No. 300 well at a depth of 2762 m. Above the section, the metamorphic rocks are overlain by a young Meso-Cenozoic cover. The schists are mainly composed of quartz, plagioclase (albite), carbonates (dolomite and siderite), mica (muscovite) and chlorite (donbassite). The discovered accessory and ore minerals in the metamorphic schists of the Zapadno-Yarotinsky area can be divided into two groups. The first group includes minerals that were formed during the metamorphism of schists, or were preserved as detrital matter. These minerals include zircon, fluorapatite, and rutile as the most stable compounds. The remaining mineralization (pyrite, sphalerite, chalcopyrite, cubanite, galena, cobaltite, barite, xenotime-(Y), goyazite, synchysite-(Nd), native silver and copper) is clearly secondary and was formed as a result of superimposed metasomatic processes. Judging from the described mineralogy, the schists underwent changes as a result of superimposed propyllitization. The temperature range of this process is determined by the formation of cubanite in association with chalcopyrite at a temperature of 200-210 оС.


2021 ◽  
Author(s):  
Sabrina Kainz ◽  
Lon Abbott ◽  
Rebecca Flowers ◽  
James Metcalf

<p>Past work has used the Southern Rocky Mountains (SRM) in the U.S. state of Colorado to illustrate the important role that rock strength plays in the histories recorded by the apatite fission track (AFT) and apatite (U-Th)/He (AHe) low-temperature thermochronometers (Flowers & Ehlers, 2018). The SRM were initially raised during the Laramide Orogeny, ca. 70-45 Ma, but consensus exists that the region also experienced a later, post-Laramide exhumation event. Flowers & Ehlers (2018) pointed to the low erosion potential of the Precambrian crystalline basement rocks that crop out in most SRM ranges as a primary reason for the abundance of 55-70 Ma “Laramide” AFT and AHe dates in the region, compared to a paucity of younger dates that would presumably be produced through erosion triggered by the post-Laramide exhumation event. South-central Colorado offers a test of this hypothesis, due to lateral variations in rock erodibility provided by the presence here of both sedimentary and crystalline Laramide ranges and adjacent sedimentary basins. The combination of our ongoing AHe study with previous south-central Colorado AFT and AHe work reveals kilometer-scale post-Laramide (Oligo-Miocene) exhumation has occurred in areas that possess thick sedimentary rock sequences whereas exhumation has been negligible where crystalline basement comprises the land surface. </p><p>South-central Colorado’s Sangre de Cristo Mountains consist of an imbricate stack of thrust sheets composed of Permian sedimentary rock. About 30 km farther east stand the Wet Mountains, another Laramide range – but one composed of Precambrian basement rock. The Raton Basin, a SRM foreland basin filled with 2 km of synorogenic fill underlain by a thick sequence of marine shale, lies south and east of the two ranges. The Wet Mountains thus form a peninsula of strong crystalline rock surrounded by more erodible sedimentary rocks to the west, south, and east. </p><p>Our study and that of Landman (2018) records at least 2 km of erosion in the Raton Basin east and south of the Wet Mountains since 25 Ma. Lindsey et al (1986) obtained 24-15 Ma AFT dates from the Paleozoic sedimentary rocks of the Sangre de Cristo Mountains, demonstrating that kilometer-scale Oligo-Miocene exhumation occurred just west of the Wet Mountains. By contrast, Kelley and Chapin (2004) obtained only pre-Laramide AFT ages between 228-110 Ma for 17 samples of Precambrian basement from the crest of the Wet Mountains. A 32 Ma ash flow tuff unconformably overlies Precambrian basement on Greenhorn Mountain, the Wet Mountains’ highest and southernmost peak. Its presence reinforces the conclusion, based on the AFT dates, that Oligo-Miocene erosion of the Wet Mountain massif has been minimal simultaneous with kilometer-scale exhumation to the west, south, and east. These results illustrate the important role that rock strength plays in determining the dates recorded in low-temperature thermochronologic studies.</p>


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