scholarly journals The Early Cretaceous in situ shallow-marine carbonates containing typical Tethyan biota in the Ishido Formation, Kanto Mountains, central Japan

2009 ◽  
Vol 115 (3) ◽  
pp. V-VI ◽  
Author(s):  
Yasuhiro Iba ◽  
Ken-ichi Hirauchi
Keyword(s):  
Early Cretaceous ◽  
Central Japan ◽  
Shallow Marine ◽  
Marine Carbonates

scholarly journals Age, microfacies and depositional environment of the Middle to Late Paleocene shallow-marine carbonates in the Sirt Basin of Libya (Upper Sabil Formation): “Are Intisar domal structures pinnacle reefs?”

Facies ◽  
2021 ◽  
Vol 67 (4) ◽  
Author(s):  
A. Vršič ◽  
H.-J. Gawlick ◽  
F. Schlagintweit ◽  
E. Machaniec ◽  
M. Gharsalla
Keyword(s):  
Depositional Environment ◽  
Planktonic Foraminifera ◽  
Carbonate Ramp ◽  
Larger Benthic Foraminifera ◽  
Shallow Marine ◽  
Late Paleocene ◽  
Marine Carbonates ◽  
Domal Structure ◽  
Sirt Basin

AbstractIn the central-eastern Sirt Basin, enigmatic Intisar domal structures host significant hydrocarbon accumulations. These structures have been commonly interpreted as pinnacle reefs/bioherms occurring in the open-marine basinal environment. Generally, pinnacle reefs/bioherms are mainly characterized by in situ carbonates. The current study challenges the Intisar pinnacle reef/bioherm model by examining one of the domal structures in terms of biostratigraphy, microfacies and depositional environment. These structures were dated using larger benthic foraminifera, which yielded a Middle to Late Paleocene age (Selandian–Early Thanetian). Thirteen microfacies types representing different carbonate ramp environments ranging from outer ramp to inner ramp, were defined. Outer ramp deposits have been observed adjacent to the domal structure, represented mainly by wackestone with small benthic and planktonic foraminifera. The outer ramp deposits are most likely isochronous to the domal structures. The lower part of the domal structures is composed mainly of foraminiferal–algal–echinodermal packstones. The upper part is characterized by foraminiferal–algal–echinodermal packstones with intercalated microbialite–coral boundstones. The euphotic inner ramp deposits are preserved on the crest of the domal structure, consisting of grainstone and packstone rich in Glomalveolina. As a result of this study, the Intisar domal structures are seen as erosional relics of a carbonate ramp and no evidence for pinnacle reef/bioherm model was found.

In situ reproductive organs of Early Cretaceous ferns from Northeast China

1997 ◽  
Vol 42 (23) ◽  
pp. 1977-1980 ◽  
Author(s):  
Deng Shenghui ◽  
Chen Fen
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Reproductive Organs

Shallow-Marine Carbonates

2012 ◽  
pp. 705-750 ◽  
Author(s):  
Dirk Knaust ◽  
H. Allen Curran ◽  
Andrei V. Dronov
Keyword(s):  
Shallow Marine ◽  
Marine Carbonates

Weathering conditions of Buddhist caves dug in soft rocks and conservation attempting from the deterioration

2021 ◽  
Author(s):  
Chiaki Oguchi ◽  
Momoko Ogawa ◽  
Kaisei Sakane ◽  
Yasuhiko Tamura
Keyword(s):  
Environmental Monitoring ◽  
Layer Structure ◽  
Physical And Mechanical Properties ◽  
Small Scale ◽  
Central Japan ◽  
Soft Rocks ◽  
Geologic Materials ◽  
Temperature And Humidity ◽  
Non Destructive

<p>The Taya Cave, a sacred Buddhist cave, locates in the precincts of Josenji Temple in Yokohama City, central Japan. The geologic materials of the hills surrounding the cave are soft rocks composed of early Quaternary sedimentary rocks. The cave has a complex three-layer structure with a total length of 570 m. The excavation of the cave is estimated to start in the Kamakura era around A.D. 1200. Since then, the cave became a training place for Buddhists until around 19 C. There are many Buddhist reliefs on the walls and ceiling inside the cave. Because the bedrock is extremely weak, the rocks easily break when they get wet again after drying, namely prone to slaking. Thus, weathering and deterioration have progressed in various parts of the cave. Many valuable Buddhist reliefs have damaged by exfoliation. The walls at several points in the cave have also collapsed on a small scale. Therefore, it is necessary to investigate such deteriorated parts in the cave by simple non-destructive tests of physical and mechanical properties by using Silver Schmidt hammer and ultrasonic velocity test. These measurements clarified the vulnerable points even in the main worship route of the cave. In October 2018, a stainless-steel door installed at the cave entrance to save from deterioration due to slaking. The effect of the door was verified as well by monitoring the environmental conditions inside the cave. Environmental monitoring results revealed that the temperature and humidity near the entrance changed most drastically in this cave. Although the door was closed only at night, the range of maximum and minimum values ​​of temperature and humidity near the entrance became smaller after installation than before. Non-destructive measurements and in situ environmental monitoring are a useful way to assess weathering without damaging geoarchaeological sites. </p>

What Factors Determine the Geometries of Fault-Associated Dolomitization Geometries in Shallow-Marine Carbonates?

2019 ◽  
pp. 157-159
Author(s):  
Shuqing Yao ◽  
Enrique Gomez-Rivas ◽  
Juan Diego Martín-Martín ◽  
David Gomez-Gras ◽  
Anna Travé ◽  
...  
Keyword(s):  
Shallow Marine ◽  
Marine Carbonates
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