What is Nummulites lyelli? Evolution in large foraminifera during the Middle Eocene, Egypt

2003 ◽  
Vol 49 (2) ◽  
pp. 171-187 ◽  
Author(s):  
M. Boukhary
Keyword(s):  
Middle Eocene ◽  
Large Foraminifera

A new hexactinellid sponge from the Eocene of Kutch, India

1993 ◽  
Vol 67 (6) ◽  
pp. 917-922 ◽  
Author(s):  
J. Keith Rigby ◽  
Manmohan Mohanti
Keyword(s):  
Middle Eocene ◽  
Western India ◽  
Single Specimen ◽  
Hexactinellid Sponge ◽  
Large Foraminifera

A single specimen of the new dictyonine hexactinellid species Verrucocoelia biswasi was collected from the Middle Eocene Fulra Limestone from Lakhpat Fort, Kutch, western India. The euretoid species is broadly bowl-shaped, 7–8 cm wide and 5–6 cm high, with walls of branched to weakly anastomosed tubes that extend upward and outward from a simple, unfluted, walled spongocoel. Skeletal strands diverge upward and outward from near the gastral surface of each tube. The sponge occurs in silty tan marl with abundant alveolinids and less common other large foraminifera, bivalves, and gastropods in sediments thought to have accumulated in a quiet, sheltered environment, possibly a lagoon.

scholarly journals New results of the lithological and paleontological study of the Middle Eocene biogenic siliceous rocks of the central part of the Ukrainian Shield

2018 ◽  
Vol 26 (1) ◽  
pp. 184-207
Author(s):  
V. L. Stefanskyi ◽  
T. A. Stefanska ◽  
M. L. Kutsevol
Keyword(s):  
Green Algae ◽  
Bacterial Communities ◽  
Middle Eocene ◽  
Geological Structure ◽  
Ukrainian Shield ◽  
Multi Stage ◽  
Siliceous Rocks ◽  
New Findings ◽  
Large Foraminifera ◽  
First Time

The present paper contains new results of complex studies on the geological structure, lithology, and fauna of the Middle Eocene siliceous rocks of the Ukrainian Shield Ingul megablock located in the vicinity of the villages of Tsybulevo, Verblyuzhka and Pervozvanovka of Kirovograd Oblast and Voronovka village of Mykolayiv Oblast. Based on new findings and analysis of malacofauna, the Middle Eocene age of the gaize-like sandstones of Verblyuzhka village was confirmed. For the first time, numerous remains of rock-forming organisms such as sponges (lithistid Demospongiae), coralline (Corallinaceae) and green algae (Dasycladales, Halimedaceae) have been found in the siliceous deposits of this region. In addition, biogenic buildups formed by organisms with carbonate (coralline and green algae, large foraminifera) and silicate (lithistid sponges) skeletons were found for the first time in the siliceous rocks of the Pervozvanovka deposit. The observed biogenic lepispheres in the studied rocks suggests that the latter have been formed with active participation of silica-producing bacterial communities. Based on the first finds of zeolites, as well as montmorillonite traces, it is forecast that "disguised" pyroclastic material is present in the gaize-like sandstones of Voronovka village. Analysis of the lithological features and the mineral and faunal composition of the studied rocks allow us to draw a conclusion about the multi-stage genesis of the Middle Eocene siliceous deposits in the central part of the Ukrainian Shield and the influence of Paleogene volcanism on their formation. It appears that volcanic activity and denudation of volcanic products caused a massive flow of SiO2 into the waters of the Middle Eocene paleobasin. This contributed to the widespread development of siliceous-skeleton organisms (in particular, silica-producing bacterial communities) that actively participated in the formation of siliceous rocks.

scholarly journals LATE CRETACEOFS SEDIMENTARY ROCK IN BARITO BASIN, INDONESIA: LITHOLOGY, PALEONTOLOGY, AND PALEOENVIRONMENT

2019 ◽  
Vol 42 (3) ◽  
pp. 131-143
Author(s):  
Akmaluddin Akmaluddin ◽  
Muhammad Virgiana A ◽  
Salahuddin Husein ◽  
Muhammad I. Novian ◽  
Nugroho I. Setiawan ◽  
...  
Keyword(s):  
Sedimentary Rock ◽  
Depositional Environment ◽  
Middle Eocene ◽  
Sedimentary Rocks ◽  
Early Oligocene ◽  
Early Tertiary ◽  
Terrestrial Environments ◽  
Large Foraminifera ◽  
Back Arc ◽  
New Evidence

The Barito Basin so far known as back-arc basin that formed by the rifting in Early Tertiary, which the oldest sedimentary rock in this basin is believed has a Middle Eocene to Early Oligocene age. However, this research will present new evidence regarding the existence of sedimentary rocks that are older than Cenozoic age in the Barito Basin. This research was carried out on Bongkang-2 well, as the main data, and other five wells which have an indication of the discovery of Pre-Tertiary sedimentary rocks, which are generally located in the northern part of the Barito Basin. Integration of mud log data, petrography, paleontology, and dip-meter data, resulting the identification of lithology, age and depositional environment, and then interpretation of the paleoenvironment of the Barito Basin in the Late Cretaceous is carried out. Based on the analysis of data, it is show that Pre-Tertiary sedimentary rocks found in the six wells analyzed has Cenomanian age, which is indicated by the presence of large foraminifera fossils in the form of Sulcoperculina sp. and Orbitolina sp. in Bongkang-2, Hayup-1 and Hayup-3 wells, as well as palynomorph fossils in the form of Cicatrico- sisporites dorogensis, A. tricornitatus, Aquilapollenites sp., Distaverrusporites margaritus and Classopolis cf. classoidesin Bagok-1 and Bagok-2 wells. In addition, based on lithological analysis, in the Bongkang-2, Hayup-1 and Hayup-2 wells lithology develops in the form of limestone, shale and sandstone, while in the Didi-1, Bagok-1 and Bagok-2 wells lithology develops in the form of shale with sandstone and pyroclastic volcaniclastics rock intercalation. Then, based on the integration of lithology and paleontology analysis, it is known that in the Cenomanian age, terrestrial environments developed in the western part of the Barito Basin, while in the eastern part the shallow marine environment developed.

The Grobogan Mud Volcano Complex: An Identification to Reveal the Opportunity of Hydrocarbon Exploration

2020 ◽  
Author(s):  
C. Jatu
Keyword(s):  
Water Analysis ◽  
Middle Eocene ◽  
Research Result ◽  
Hydrocarbon Exploration ◽  
System Model ◽  
Mud Volcano ◽  
Hydrocarbon Potential ◽  
Mud Volcanoes ◽  
Central Java ◽  
Surface Data

Mud volcanoes in Grobogan are referred as the Grobogan Mud Volcanoes Complex in Central Java where there is evidence of oil seepages. This comprehensive research is to determine the characteristics and hydrocarbon potential of the mud volcanoes in the Central Java region as a new opportunity for hydrocarbon exploration. The Grobogan Mud Volcano Complex consists of eight mud volcanoes that have its characteristics based on the study used the geological surface data and seismic literature as supporting data on eight mud volcanoes. The determination of geological surface characteristics is based on geomorphological analysis, laboratory analysis such as petrography, natural gas geochemistry, water analysis, mud geochemical analysis and biostratigraphy. Surface data and subsurface data are correlated, interpreted, and validated to make mud volcano system model. The purpose of making the mud volcanoes system model is to identify the hydrocarbon potential in Grobogan. This research proved that each of the Grobogan Mud Volcanoes has different morphological forms. Grobogan Mud Volcanoes materials are including muds, rock fragments, gas, and water content with different elemental values. Based on this research result, there are four mud volcano systems models in Central Java, they are Bledug Kuwu, Maesan, Cungkrik, and Crewek type. The source of the mud is from Ngimbang and Tawun Formation (Middle Eocene to Early Miocene) from biostratigraphy data and it been correlated with seismic data. Grobogan Mud Volcanoes have potential hydrocarbons with type III kerogen of organic matter (gas) and immature to early mature level based on TOC vs HI cross plot. The main product are thermogenic gas and some oil in relatively small quantities. Water analysis shows that it has mature sodium chloride water. This analysis also shows the location was formed within formations that are deposited in a marine environment with high salinity. Research of mud volcanos is rarely done in general. However, this comprehensive research shows the mud volcano has promising hydrocarbon potential and is a new perspective on hydrocarbon exploration.

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