scholarly journals A compilation and characterisation of lithics in kimberlite and common maar-diatremes and tephra ring deposits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. K. Fitzgerald ◽  
J. D. L. White

AbstractMaar-diatreme volcanoes are the second-most common type on land, occurring in volcanic fields within all major tectonic environments. Their deposits typically contain an abundance of lithic fragments quarried from the substrate, and many contain large, deep-sourced lithic fragments that were erupted to the surface. Primary volcaniclastic deposits fill the diatreme structure formed during eruption. There is negligible inelastic deformation of diatreme-adjacent country rock, indicating that country rock is removed to create the diatreme structures, either by being shifting downward below observable levels, ejected upward to contribute to surficial deposits, or dissolved and hidden in magma erupted or intruded at depth. No previous study has systematically reviewed and analysed the reported lithic fragments of maar-diatreme systems. We present a comprehensive compilation from published work of lithic characteristics in maar ejecta rings and in diatreme deposits of both common and kimberlite maar-diatremes. For maar-diatremes and their tephra ring deposits, we find no correlations among lithic clast sizes, shapes, depositional sites, and excavation depths. This is difficult to reconcile with models involving systematic diatreme deepening coupled with tephra-ring growth, but consistent with those involving chaotic explosions and mixing. Larger amounts of data are needed to further examine how these types of volcanoes operate.

2021 ◽  
Author(s):  
Michelle Kathleen Fitzgerald ◽  
James Daniel Lee White

Abstract Maar-diatreme volcanoes are the second-most common type on land, occurring in volcanic fields within all major tectonic environments. Their deposits typically contain an abundance of lithic fragments quarried from the substrate, and many contain large, deep-sourced lithic fragments that were erupted to the surface. Primary volcaniclastic deposits fill the diatreme structure formed during eruption. There is negligible inelastic deformation of diatreme-adjacent country rock, indicating that country rock is removed to create the diatreme structures, either by being shifting downward below observable levels, ejected upward to contribute to surficial deposits, or dissolved and hidden in magma erupted or intruded at depth. No previous study has systematically reviewed and analysed the reported lithic fragments of maar-diatreme systems. We present a comprehensive compilation from published work of lithic characteristics in maar ejecta rims and in diatreme deposits of both common and kimberlite maar-diatremes. For maar-diatremes and their tephra ring deposits, we find no correlations among lithic clast sizes, shapes, depositional sites, and excavation depths. This is difficult to reconcile with models involving systematic diatreme deepening coupled with tephra-ring growth, but consistent with those involving chaotic explosions and mixing. Larger amounts of data are needed to further examine how these types of volcanoes operate.


1998 ◽  
Vol 35 (10) ◽  
pp. 1143-1151 ◽  
Author(s):  
Daniel Holm ◽  
Daniel Lux

The 1470 Ma Wolf River batholith of northeastern Wisconsin is one of the oldest and largest intrusive sequences of the Middle Proterozoic magmatic suite that trends across the continent from Labrador to southern California. The presence of miarolitic cavities in portions of the batholith and in associated plutons (Wausau syenite complex) and equilibrium considerations suggest a shallow emplacement depth (i.e., <4 km). However, these data contrast with published Rb/Sr biotite ages, which suggest much of the batholith was uplifted through mid-crustal temperatures well after intrusion. To address this problem better, we have obtained four biotite 40Ar/39Ar dates from a transect across the southwestern portion of the batholith, one date from the ~1520 Ma Wausau syenite complex, and another from rocks metamorphosed during the Early Proterozoic Penokean orogeny. The two oldest dates are concordant (within error) with the crystallization age of the batholith, suggesting rapid cooling after intrusion and hence shallow emplacement depth. Cooling dates young to the south-southeast, however, and the youngest dates within the batholith (~1400 Ma) are concordant with previous Rb/Sr biotite dates and with the Ar/Ar biotite date from the adjacent country rock. The data suggest slow cooling and southeast-side-up tilting of this portion of the exposed batholith from mid-crustal temperatures (~300°C). Postemplacement uplift and tilting of the batholith appear related to differential isostatic uplift driven by substantial original thickness variations of the intrusion.


2011 ◽  
Vol 23 (3) ◽  
pp. 268-280 ◽  
Author(s):  
David H. Elliot ◽  
Craig G. Grimes

AbstractThe Triassic Lashly Formation occurs to the east of Mount Brooke at Coombs Hills. Previously established informal members B, C, and D of the Lashly Formation are now identified at Coombs Hills. Lashly Formation member D passes up into a poorly exposed interval of silicic shard-bearing fine-grained sandstone and tuff, which is correlated with the Jurassic Shafer Peak Formation of north Victoria Land and Hanson Formation of the Beardmore Glacier region. Lashly Formation members C and D are intruded by three phreatic explosion pipes, resulting from emplacement of Ferrar Dolerite intrusions at depth and associated explosive steam generation. These pipes, ranging up to 180 m in horizontal dimension, comprise sedimentary clasts in a sand matrix, most of which was locally derived. Pipe margins are mainly ill defined and adjacent country rock is commonly disaggregated or shattered, although retaining stratigraphic order. Locally, thin basalt intrusions have interacted with coal beds.


Author(s):  
O. T. Minick ◽  
E. Orfei ◽  
F. Volini ◽  
G. Kent

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).


Author(s):  
S. Siew

Mesothelial cells constitute the lining of the three serous sacs of the body i.e. the pleura, pericardium and peritoneum. The more common type of malignant neoplasia of the serous sacs is seeding by metastatic tumors and primary malignancy of the mesothelium is unusual. Of the three sacs, the pleura is the most common site of malignant mesothelioma. Involvement of the peritoneum is extremely rare.We report 3 cases of malignant mesothelioma of the peritoneum. All of them were female. Their ages were 57, 67 and 72 years, respectively. The patients presented with abdominal discomfort and/or ascites. The extent of the tumors ranged from a peritoneal implant to widespread infiltration of the peritoneum and omentum. Histologic examination in Case 1 showed the presence of a diffusely infiltrating papillary mesothelioma without a sarcomatoid component. A mesodermal element was present in the other two cases. In order to establish a morphological diagnosis of malignant mesothelioma, the possibility has to be excluded of a metastatic adenocarcinoma.


Author(s):  
Chávez Hernández María Margarita ◽  
Jiménez Báez María Valeria ◽  
Armijo Medina María Fernanda ◽  
Domínguez Leyva Jorge Miguel ◽  
Góngora Valencia Karen Alejandra ◽  
...  

Prolactinomas are the most common type of functional pituitary tumor. The present manuscript is an update on the treatment modalities for prolactinomas. Effective hyperprolactinemia treatment is of great importance, due to its potential deleterious effects including infertility, gonadal dysfunction and osteoporosis. Dopamine agonist therapy is the first line of treatment for prolactinomas; recurrence of disease after cessation of the drug may occur in patients. Its safety profile remains high, allowing its use during pregnancy.


Author(s):  
Amna Mohamed Ahmed ◽  
Towmader Awad ◽  
Hajer Yousif ◽  
Reem Nahari ◽  
Omnia Abdelrhman ◽  
...  

Computed Tomography (CT) is the most commonly used imaging modality in the evaluation of cerebral hemorrhage in the head trauma patients. Objective: To study the incidence of a cerebral hemorrhage in traumatic patients using computed tomography. Method: This retrospective study was conducted at King Khalid hospital in Tabuk city, Saudi Arabia, in the radiology department, in the period from September 2018 to April 2020. The study was done by collecting 471 CT reports of patients all of them were exposed to head trauma with deferent reasons. The data were analyzed by Statistical Package for the Social Sciences (SPSS) program (ver. 20) and presented in tables and graphs according to the checklist which includes: patient age, gender, type of trauma, CT finding, and type of hemorrhage. Results: The most age group suffered from head trauma was less than 20 years percentage (55%), The male patients more exposed to head trauma than female patients with percentage (84.5%), the road traffic accident (RTA) is the most common type of trauma by percentage (63.5%), according to the CT finding; the cerebral hemorrhage represented (15.5%) with the highest percentage in a subdural hematoma (31.2%), the fracture represented (2.8%) while the normal appearance represented (81.7%) as the highest percentage. Conclusion: Most of the traumatic brain injury in patients caused cerebral hemorrhage and the CT scan reports show that: the common type of cerebral hemorrhage is subdural hematoma and it is common in males which exposed to (RTA) in the age group (21 - 40) years old.


Author(s):  
Bhavani J ◽  
Sunil Kumar Prajapati ◽  
Ravichandran S

Cancer is assemblage diseases involving abnormal cell growth amid the potential of spread to other parts of the body due to tobacco use are the cause of about of cancer deaths. Another 10% is due to obesity, poor diet & drinking alcohol. In 2012 about 14.1 million new cases of cancer occurred globally. In females, the most common type is breast cancer. Cisplatin also known as cytophosphane is a nitrogen mustard alkylating agent from the oxazophosphinans groups were used to treat cancers & autoimmune disorders. Based on the above reasons I will fix the aim Preparation characterization of Cisplatin- nano particles  &  its anticancer activity. Solid tumor volume examination report showed that the assessment of different day indication 15,20,25 & 30th variations of different groups of tumor volumes were decreased CPG Nanoparticles (100 mg/kg)+ DAL(15th day 4.97±0.24↓), (20th day 0.6±0.13↓), (25th day 1.35±0.30↓) & (30th day 1.89±0.13↓).


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