• Title/Summary/Keyword: 분

Search Result 24,332, Processing Time 0.061 seconds

Usefulness of Pulsatile Flow Aortic Aneurysm Phantoms for Stent-graft Placement (스텐트그라프트 장치술을 위한 대동맥류 혈류 팬텀의 유용성)

  • Kim, Tae-Hyung;Ko, Gi-Young;Song, Ho-Young;Park, In-Kook;Shin, Ji-Hoon;Lim, Jin-Oh;Kim, Jin-Hyoung;Choi, Eu-Gene K.
    • Journal of radiological science and technology
    • /
    • v.30 no.3
    • /
    • pp.205-212
    • /
    • 2007
  • To evaluate the feasibility and efficacy of a pulsatile aortic aneurysm phantoms for in-vitro study. The phantoms consisted of a pulsating motor part(heart part) and an aortic aneurysm part, which mimicked true physiologic conditions. The heart part was created from a high-pressured water pump and a pulsatile flow solenoid valve for the simulation of aortic flow. The aortic aneurysm part was manufactured from paper clay, which was placed inside a acrylic plastic square box, where liquid silicone was poured. After the silicone was formed, the clay was removed, and a silicone tube was used to connect the heart and aneurysm part. We measured the change in pressure as related to the opening time(pulse rate, Kruskal-Wallis method) and pressure before and after the stent-graft implantation(n = 5, Wilcoxon's signed ranks test). The changes in blood pressures according to pulse rate were all statistically significant(p<0.05). The systolic/diastolic pressures at the proximal aorta, the aortic aneurysm, and the distal aorta of the model were $157.80{\pm}1.92/130.20{\pm}1.92$, $159.40{\pm}1.14/134.00{\pm}2.92$, and $147.20{\pm}1.480/129.60{\pm}2.70\;mmHg$, respectively, when the pulse rate was 0.5 beat/second. The pressures changed to $161.40{\pm}1.34/90.20{\pm}1.64$, $175.00{\pm}1.58/93.00{\pm}1.58$, and $176.80{\pm}1.48/90.80{\pm}1.92\;mmHg$, respectively, when the pulse rate was 1.0 beat/second, and $159.40{\pm}1.82/127.20{\pm}1.48$, $166.60{\pm}1.67/138.00{\pm}1.87$, and $161.00{\pm}1.22/135.40{\pm}1.67\;mmHg$, respectively, when it was 1.5 beat/second. When pulse rate was set at 1.0 beat/second, the pressures were $143.60{\pm}1.67/90.20{\pm}1.64$, $147.20{\pm}1.92/84.60{\pm}1.82$, and $137.40{\pm}1.52/88.80{\pm}1.64\;mmHg$ after stent-graft implantation. The changes of pressure before and after stent-graft implantation were statistically significant(p<0.05) except the diastolic pressures at the proximal(p =1.00) and distal aorta(p=0.157). The aortic aneurysm phantoms seems to be useful for the evaluation of the efficacy of stent-graft before animal or clinical studies because of its easy reproducibility and ability to display a wide range of pressures.

  • PDF

Analysis of the Causes of Subfrontal Recurrence in Medulloblastoma and Its Salvage Treatment (수모세포종의 방사선치료 후 전두엽하방 재발된 환자에서 원인 분석 및 구제 치료)

  • Cho Jae Ho;Koom Woong Sub;Lee Chang Geol;Kim Kyoung Ju;Shim Su Jung;Bak Jino;Jeong Kyoungkeun;Kim Tae_Gon;Kim Dong Seok;Choi oong-Uhn;Suh Chang Ok
    • Radiation Oncology Journal
    • /
    • v.22 no.3
    • /
    • pp.165-176
    • /
    • 2004
  • Purpose: Firstly, to analyze facto in terms of radiation treatment that might potentially cause subfrontal relapse in two patients who had been treated by craniospinal irradiation (CSI) for medulloblastoma, Secondly, to explore an effective salvage treatment for these relapses. Materials and Methods: Two patients who had high-risk disease (T3bMl, T3bM3) were treated with combined chemoradiotherapy CT-simulation based radiation-treatment planning (RTP) was peformed. One patient who experienced relapse at 16 months after CSI was treated with salvage surgery followed by a 30.6 Gy IMRT (intensity modulated radiotherapy). The other patient whose tumor relapsed at 12 months after CSI was treated by surgery alone for the recurrence. To investigate factors that might potentially cause subfrontal relapse, we evaluated thoroughly the charts and treatment planning process including portal films, and tried to find out a method to give help for placing blocks appropriately between subfrotal-cribrifrom plate region and both eyes. To salvage subfrontal relapse in a patient, re-irradiation was planned after subtotal tumor removal. We have decided to treat this patient with IMRT because of the proximity of critical normal tissues and large burden of re-irradiation. With seven beam directions, the prescribed mean dose to PTV was 30.6 Gy (1.8 Gy fraction) and the doses to the optic nerves and eyes were limited to 25 Gy and 10 Gy, respectively. Results: Review of radiotherapy Portals clearly indicated that the subfrontal-cribriform plate region was excluded from the therapy beam by eye blocks in both cases, resulting in cold spot within the target volume, When the whole brain was rendered in 3-D after organ drawing in each slice, it was easier to judge appropriateness of the blocks in port film. IMRT planning showed excellent dose distributions (Mean doses to PTV, right and left optic nerves, right and left eyes: 31.1 Gy, 14.7 Gy, 13.9 Gy, 6.9 Gy, and 5.5 Gy, respectively. Maximum dose to PTV: 36 Gy). The patient who received IMRT is still alive with no evidence of recurrence and any neurologic complications for 1 year. Conclusion: To prevent recurrence of medulloblastoma in subfrontal-cribriform plate region, we need to pay close attention to the placement of eye blocks during the treatment. Once subfrontal recurrence has happened, IMRT may be a good choice for re-irradiation as a salvage treatment to maximize the differences of dose distributions between the normal tissues and target volume.

Comparison of the Result of Radiation Alone and Radiation with Daily Low Dose Cisplatin in Management of Locally Advanced Cervical Cancer (국소적으로 진행된 자궁경부암에서 방사선 단독치료와 방사선 및 저용량 Cisplatin 항암화학요법 병용치료의 비교)

  • Kim Hun Jung;Kim Woo Chul;Lee Mee Jo;Kim Chul Su;Song Eun Seop;Loh John J K.
    • Radiation Oncology Journal
    • /
    • v.22 no.3
    • /
    • pp.200-207
    • /
    • 2004
  • Purpose: An analysis was to compare the results of radiation alone with those of radiation with dally low dose cisplatin as a radiation sensitizer in locally advanced cervical cancer. Materials and Methods: A retrospective analysis of 59 patients diagnosed with locally advanced uterine cervix cancer between December 1996 and March 2001 was peformed. Thirty one patients received radiation alone and 28 patients received dally low dose cisplatin, as a radiation sensitizer, and radiation therapy. The median follow-up period was 34 months, ranging from 2.5 to 73 months. The radiation therapy consisted of 4500 cGy external beam irradiation to the whole pelvis (midline block after 3060 cGy), a 900$\~$l,000 cGy boost to the involved parametrium and high dose-rate intracavitary brachytherapy (a total dose of 3,000$\~$3,500 cGy/500 cGy per fraction to point A, twice per week). In the chemoradiation group, 10 mg of daily intravenous cisplatin was given daily from the 1st day of radiation therapy to the 20th day of radiation therapy. According to the FIGO classification, the patients were subdivided into 51 (86.4$\%$) and 8 (13.6$\%$) stages IIB and stage IIIB, respectively. Results: The overall 5 year survival rate was 65.65$\%$ and according to treatment modality were 56.75$\%$ and 73.42$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.180). The 5 year disease-free survival rates were 49.39$\%$ and 63.34$\%$ in the radiation alone and chemoradiatoin groups, respectively (p=0.053), The 5 year locoregional control rates were 52.34$\%$ and 73.58$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.013). The 5 year distant disease-free survival rates were 59.29$\%$ and 81.46$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.477), Treatment related hematologic toxicity were prominent in the chemoradiation group. Leukopenia $\geq$grade) occurred in 3.2$\%$and 28.5$\%$ of the radiation alone and chemoradiation groups, respectively (p=0.02). There were no statistical differences in the incidences of vesical, rectal and small bowel complications between two groups. Conclusion: Radiation therapy with low dose cisplatin did not improve the rates of survival and response rates, but did improve the rate of disease free survival and locoregional control rates In locally advanced cervical cancer. The incidence of bone marrow suppression was higher in the chemoradiation group.

Clinical Features and the Natural History of Dietary Protein Induced Proctocolitis: a Study on the Elimination of Offending Foods from the Maternal Diet (식품 단백질 유발성 직결장염의 임상 소견과 식이 조절에 관한 연구)

  • Choi, Seon Yun;Park, Moon Ho;Choi, Won Joung;Kang, Una;Oh, Hoon Kyu;Kam, Sin;Hwang, Jin-Bok
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • v.8 no.1
    • /
    • pp.21-30
    • /
    • 2005
  • Purpose: The aim of this study was to identify the clinical features and natural history of dietary protein induced proctocolitis (DPIPC) and to detect the causative foods of DPIPC, and to evaluate the effect of elimination of the foods on the course of the disease. Methods: Between March 2003 and July 2004, data from 30 consecutive patients with DPIPC who were followed for over 6 months, was reviewed. The diagnostic criterion used for DPIPC was an increase in the number of eosinophils in the lamina propria (${\geq}60per$ 10 high-power fields). In breast feeding mothers, 5 highly allergenic foods were eliminated from the maternal diet for 7 days, namely, allergenic food groups such as dairy products, eggs, nuts and soybean, fish and shellfish, and wheat and buckwheat. We observed the disappearance or appearance of hematochezia after elimination or challenge with the offending foods. Results: Before diagnosis infants were breast-fed (93.3%) or formula-fed (6.7%). Mean age at symptom onset was $11.5{\pm}5.1$ (5~24) weeks, and mean age at diagnosis was $17.8{\pm}9.5$ (8~56) weeks. Duration from symptom onset to diagnosis was $6.3{\pm}6.7$ (0~36) weeks. Mean peripheral blood eosinophil count was $478{\pm}320$ (40~1,790)/$mm^3$ and eosinophilia (> $250/mm^3$) was observedin 90.0% of patients. None of patients were found to have an increased serum IgE level. Of 15 patients that received sigmoidoscopy, nodular hyperplasia with erosion was observed in 93.3%. Of 27 patients whose mother ate the diet eliminated the 5 food groups, hematochezia diappeared in 74.1% of patients. Offending foods were identified as dairy products (37.5%), wheat and buckwheat (27.5%), fish and shellfish (20.0%), nuts and soybean (7.5%) and eggs (7.5%). A free maternal diet without patient's clinical symptoms was achieved at $29.4{\pm}8.7$ (9~44) weeks of patient's age, and a free baby diet without blood in stools was achieved at $37.5{\pm}9.7$ (12~56) weeks of age. Conclusion: DPIPC commonly occurs in exclusively breast-fed babies. Elimination of the above-mentioned 5 hyper-allergenic food groups from the maternal diet for 7days enables the detection of the offending foods. DPIPC is a transient disorder and 96.0% of patients can tolerate the offending foods at 12 months of age.

  • PDF

Gastroduodenoscopic Findings and Effect of Therapy of Helicobacter pylori Infection in Children (소아 Helicobacter pylori 감염의 상부 위장관 내시경 소견 및 치료 효과)

  • Rhee, Kyung Shin;Park, Jae Ock
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • v.8 no.1
    • /
    • pp.12-20
    • /
    • 2005
  • Purpose: Helicobacter pylori infection is known to be associated with acute or chronic abdominal pain and upper gastrointestinal bleeding in children. This study was performed to analyze the gastroduodenoscopic findings and the efficacy of triple therapy with omeprazole, amoxicillin and clarithromycin between one and two weeks of duration in children with H. pylori infection. Methods: We have assessed retrospectively 60 patients presented with acute or chronic abdominal pain or upper gastrointestinal bleeding. H. pylori infection was confirmed by endoscopic biopsy and rapid urease test. Out of 60 patients, 30 patients were treated with a combination of omeprazole, amoxicillin, and clarithromycin for one week, and the other 30 patients were treated for two weeks with the same medication. Efficacy of treatment was assessed 4 weeks after the termination of treatment by using the $^{13}C$ urea breath test. Results: The 60 patients with the complaint of diffuse abdominal pain, epigastric pain, vomiting or hematemesis were included in this study. One-week treatment group (group I) consisted of 30 patients (14 male, 16 female) with mean age of $11.6{\pm}2.67years$. Two-week treatment group (group II) consisted of 30 patients (11 male, 19 female) with mean age of $10.7{\pm}4.17years$. In group I, H pylori were eradicated in 26 out of 30 patients (86.7%). In group II, H. pylori were eradicated in 26 out of 30 children (86.7%). Both groups did $^{13}C$ urea breath test after 4 weeks after termination of the triple therapy. The eradication rates were same in both groups as 86.7%, 26 out of 30 patients in each group. The results of endoscopy were nodular gastritis 26 (43.3%), erosive gastritis 10 (16.7%), hemorrhagic gastritis 7 (11.7%), gastric ulcer 2 (3.3%) and normal finding 15 (25.0%). Conclusion: In this study, the nodular gastritis was most common endoscopic findings with H. pylori positive patients. The eradication rate of H. pylori with omeprazole, amoxicillin and clarithromycin was 86.7% and it would be highly effective as primary treatment with no significant differences in the eradication rate between one-week and two-week treatment groups. However, we should need more long-term follow-up data.

  • PDF

Clinical Outcomes of Off-pump Coronary Artery Bypass Grafting (심폐바이패스 없는 관상동맥우회술의 임상성적)

  • Shin, Je-Kyoun;Kim, Jeong-Won;Jung, Jong-Pil;Park, Chang-Ryul;Park, Soon-Eun
    • Journal of Chest Surgery
    • /
    • v.41 no.1
    • /
    • pp.34-40
    • /
    • 2008
  • Background: Off-pump coronary artery bypass grafting (OPCAB) shows fewer side effects than cardiopulmonary by. pass, and other benefits include myocardial protection, pulmonary and renal protection, coagulation, inflammation, and cognitive function. We analyzed the clinical results of our cases of OPCAB. Material and Method: From May 1999 to August 2007, OPCAB was performed in 100 patients out of a total of 310 coronary artery bypass surgeries. There were 63 males and 37 females, from 29 to 82 years old, with a mean age of $62{\pm}10$ years. The preoperative diagnoses were unstable angina in 77 cases, stable angina in 16, and acute myocardial infarction in 7. The associated diseases were hypertension in 48 cases, diabetes in 42, chronic renal failure in 10, carotid artery disease in 6, and chronic obstructive pulmonary disease in 5. The preoperative cardiac ejection fraction ranged from 26% to 74% (mean $56.7{\pm}11.6%$). Preoperative angiograms showed three-vessel disease in 47 cases, two-vessel disease in 25, one-vessel disease in 24, and left main disease in 23. The internal thoracic artery was harvested by the pedicled technique through a median sternotomy in 97 cases. The radial artery and greater saphenous vein were harvested in 70 and 45 cases, respectively (endoscopic harvest in 53 and 41 cases, respectively). Result: The mean number of grafts was $2.7{\pm}1.2$ per patient, with grafts sourced from the unilateral internal thoracic artery in 95 (95%) cases, the radial artery in 62, the greater saphenous vein in 39, and the bilateral internal thoracic artery in 2. Sequential anastomoses were performed in 46 cases. The anastomosed vessels were the left anterior descending artery in 97 cases, the obtuse marginal branch in 63, the diagonal branch in 53, the right coronary artery in 30, the intermediate branch in 11, the posterior descending artery in 9 and the posterior lateral branch in 3. The conversion to cardiopulmonary bypass occurred in 4 cases. Graft patency was checked before discharge by coronary angiography or multi-slice coronary CT angiography in 72 cases, with a patency rate of 92.9% (184/198). There was one case of mortality due to sepsis. Postoperative arrhythmias or myocardial in-farctions were not observed. Postoperative complications were a cerebral stroke in 1 case and wound infection in 1. The mean time of respirator care was $20{\pm}35$ hours and the mean duration of stay in the intensive care unit was $68{\pm}47$ hours. The mean amounts of blood transfusion were $4.0{\pm}2.6$ packs/patient. Conclusion: We found good clinical outcomes after OPCAB, and suggest that OPCAB could be used to expand the use of coronary artery bypass grafting.

Effects of Crude Protein Levels in Total Mixed Rations on Dry Matter Intake, Digestibility and Nitrogen Balance in Early Pregnant Korean Black Goats (섬유질배합사료 내 조단백질 수준이 임신초기 흑염소의 건물섭취량, 소화율 및 질소출납에 미치는 영향)

  • HwangBo, Soon;Choi, Sun-Ho;Lee, Sung-Hoon;Kim, Sang-Woo;Kim, Young-Keun;Sang, Byung-Don;Jo, Ik-Hwan
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.27 no.2
    • /
    • pp.93-100
    • /
    • 2007
  • This study was conducted to determine the effects of different levels (10, 12 and 15%) of crude protein (CP) in total mixed ration (TMR) on dry matter intake, digestibility and nitrogen balance of Korean black goats in the stage of early pregnancy and to obtain information on their optimal dietary levels of CP. In the present study, 12 Does of Korean black goats in the early pregnancy were allotted to four unreplicated groups by dietary level of CP and then they were housed in individual metabolism cages with completely randomized design throughout 30 days with 20 days adaptation and 10 days collection periods. Does in Control were fed a conventional diet and does in TMR10, TMR12 and TMR15 were fed a diet adjusted to about 10, 12 and 15% CP, respectively. Dry matter(DM) contents ranged from 89 to 91% in treatments. There were no differences fur fiber contents among three CP levels of TMR, showing that ADF and NDF had 18.57 to 19.85, and 53.41 to 54.80, respectively. Crude protein contents for three TMR treaements had 10.61, 12.15 and 14.97%, respectively. However, non-fibrous carbohydrate (NFC) contents decreased with increasing CP levels in treatments. Meanwhile, Intakes of DM, nutrients and digestible nutrients were significantly (p<0.05) higher in TMR15 and control than in TMR10 and TMR12. Moreover, DM intake per metabolic body weight and theit ratio per body weight was significantly (p<0.05) higher for control and TMR15 than other treatments. DM digestibility was not significantly different among treatments, but ether extract digestibility of treatments was significantly (p<0.05) higher than that of control, but there was no significant difference among treatments. Nitrogen retention significantly (p<0.05) increased with increasing CP levels in TMR, and TMR15 was highest among treatments. Our results showed that the increasing CP levels in TMR increased DM intake and nitrogen retention and suggested that the optimal dietary CP levels under TMR feeding system in early pregnant Korean black goats could be estimated for at least 15%.

Fermentation Characteristics of Juice Pomace Feed by Horse Feces Microbes (말분변 미생물을 이용한 주스박 사료의 발효 특성)

  • Hwang, Won-Uk;Kim, Gyeom-Heon;Niu, Kai-Min;Lim, Joung-Ho;Woo, Jae-Hoon;Chae, Hyun-Seok;Park, Nam-Geon;Kim, Soo-Ki
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.37 no.4
    • /
    • pp.290-300
    • /
    • 2017
  • In vitro fermentation was conducted to figure out alternative fiber sources for horse feed. For the development of value-added products as a horse feed resource, the pomaces from apple, carrot, grape, and citrus were fermented under solid-state conditions in the presence of 60% soybean meal with 40% of each fruit pomace at 60% of moisture content. Lactobacillus plantarum SK3873, Lactobacillus plantarum SK3893, Weissella cibaria SK3880, and Bacillus subtilis SK3889 were isolated from the fermented fruit pomace by inoculation of horse feces. For the growth of Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus plantarum, they were inoculated in 3-step order at 0, 12, and 24 h, respectively. The fruit pomace was fermented for 48 h at $35^{\circ}C$. The pH of the apple, carrot, grape, citrus and all mixed pomaces decreased from 5.45~6.25 to 4.40~4.77. Microbial growth was maintained at $10^8{\sim}10^9cfu/g$. After 12 and 24 h incubation, dry matter of carrot pomace were highest at 54.84 and 56.66%, respectively (P<0.05) and that of grape pomace was lower than others during fermentation (P<0.05). Dry matter was generally reduced by about 20%. NDF decreased gradually or maintained after 24 h, indicating the fiber degradation. Ash content tended to decrease during fermentation. After 48 hours fermentation, Bacillus, yeast and Lactobacillus showed an excellent growth by using juice by-products. These results suggest that fermented juice pomace has a potential as horse feedstuff with probiotics to maintain beneficial microflora in horse gut.

THE EFFECT OF IRRADIATION MODES ON POLYMERIZATION AND MICROLEAKAGE OF COMPOSITE RESIN (광조사 방식이 복합레진의 중합과 누출에 미치는 영향)

  • Park, Jong-Jin;Park, Jeong-Won;Park, Sung-Ho;Park, Ju-Myong;Kwon, Tae-Kyung;Kim, Sung-Kyo
    • Restorative Dentistry and Endodontics
    • /
    • v.27 no.2
    • /
    • pp.158-174
    • /
    • 2002
  • The aim of this study was to investigate the effect of light irradiation modes on polymerization shrinkage, degree of cure and microleakage of a composite resin. VIP$^{TM}$ (Bisco Dental Products, Schaumburg, IL, USA) and Optilux 501$^{TM}$ (Demetron/Kerr, Danbury, CT, USA) were used for curing Filtek$^{TM}$ Z-250 (3M Dental Products, St. Paul., MN, USA) composite resin using following irradiation modes: VIP$^{TM}$ (Bisco) 200mW/$\textrm{cm}^2$ (V2), 400mW/$\textrm{cm}^2$ (V4), 600mW/$\textrm{cm}^2$ (V6), Pulse-delay (200 mW/$\textrm{cm}^2$ 3 seconds, 5 minutes wait, 600mW/$\textrm{cm}^2$ 30seconds, VPD) and Optilux 501$^{TM}$ (Demetron/Kerr) C-mode (OC), R-mode (OR). Linear polymerization shrinkage of the composite specimens were measured using Linometer (R&B, Daejeon, Korea) for 90 seconds for V2, V4, V6, OC, OR groups and for up to 363 seconds for VPD group (n=10, each). Degree of conversion was measured using FTIR spectrometer (IFS 120 HR, Bruker Karlsruhe, Germany) at the bottom surface of 2 mm thick composite specimens V2, Y4, V6, OC groups were measured separately at five irradiation times (5, 10, 20, 40, 60 seconds) and OR, VPD groups were measured in the above mentioned irradiation modes (n=5 each). Microhardness was measured using Digital microhardness tester (FM7, Future-Tech Co., Tokyo, Japan) at the top and bottom surfaces of 2mm thick composite specimens after exposure to the same irradiation modes as the test of degree of conversion(n=3, each). For the microleakage test, class V cavities were prepared on the distal surface of the ninety extracted human third molars. The cavities were restored with one of the following irradiation modes : V2/60 seconds, V4/40 seconds, V6/30 seconds, VPD , OC and OR. Microleakage was assessed by dye penetration along enamel and dentin margins of cavities. Mean polymerization shrinkage, mean degree of conversion and mean microhardness values for all groups at each time were analyzed using one-way ANOVA and Duncan's multiple range test, and using chi-square test far microleakage values. The results were as follows : . Polymerization shrinkage was increased with higher light intensity in groups using VIP$^{TM}$ (Bisco) : the highest with 600mW/$\textrm{cm}^2$, followed by Pulse-delay, 400mW/$\textrm{cm}^2$ and 200mW/$\textrm{cm}^2$ groups, The degree of polymerization shrinkage was higher with Continuous mode than with Ramp mode in groups using Optilux 501$^{TM}$ (Demetron/Kerr). . Degree of conversion and microhardness values were higher with higher light intensity. The final degree of conversion was in the range of 44.7 to 54.98% and the final microhardness value in the range of 34.10 to 56.30. . Microleakage was greater in dentin margin than in enamel margin. Higher light intensity showed more microleakage in dentin margin in groups using VIP$^{TM}$ (Bisco). The microleakage was the lowest with Continuous mode in enamel margin and with Ramp mode in dentin margin when Optilux 501$^{TM}$ (Demetron/Kerr) was used.

Structural and Compositional Characteristics of Skarn Zinc-Lead Deposits in the Yeonhwa-Ulchin Mining District, Southeastern Taebaegsan Region, Korea Part II : The Yeonhwa II Mine (연화(蓮花)-울진광산지대(蔚珍鑛山地帶) 스카른연(鉛)·아연광상(亞鉛鑛床)의 구조적(構造的) 및 성분적(成分的) 특징(特徵) 기이(其二) : 제2연화광산(第二蓮花鑛山))

  • Yun, Suckew
    • Economic and Environmental Geology
    • /
    • v.12 no.3
    • /
    • pp.147-176
    • /
    • 1979
  • The Yeonhwa II zinc-lead mine is characterized by a dozen of moderately dipping tabular orebodies of skarn and zinc-lead sulfides, developed in accordance with the ENE-trending bedding thrusts and bedding planes of the Pungchon Limestone and underlying Myobong Formation, mostly along the contacts of a ENE-trending sill and a NW-trending dike of quartz mononite porphyry. The orebodies occur in three groups: (1) the footwall Wolgok orebodies with respect to the sill, (2) the hangingwall Wolgok orebodies, and (3) the Seongok orebodies extended from dike contacts into carbonate beds. Mineral compositions of these orebodies are dominated by calc-silicates (skarn) associated with ore minerals of sphalerite, galena, and chalcopyrite, as well as sulfide gangue of pyrrhotite. A pair of exo- and endo-skerns in the Wolgok footwall contact aureole between the Pungchon Limestone and quartz monzonite porphyry on the -120 level represents a well-developed symmetrical pattern of mineral zoning: a garnet/quartz zone in the center of exoskarn, two zones of pyroxene with ore minerals on both sides of the garnet/quartz zone, further outwards-an epidote/chlorite-bearing hornfelsic zone in the Myobong slate beyond a zone of unaffected limestone, and an epidote-dominated zone of endo skarn on the opposite side toward fresh quartz monzonite porphyry. These features indicate a combination of two effects on the skarn formation: (1) differences in composition of the host rocks(sedimentary and ignous), and (2) progressive outward migration of inner zones on outer zones on the course of metasomatic replacement of the pre-existing minerals. Microprobe analyses of garnet, pyroxene, pyroxenoids, epidote, and chlorite for nine major elements on a total of 23 mineral grains revealed that: the pyroxenes are hedenbergitic, in most zones, with a gradual decrease of Fe- and Mn-contents toward the central zone, whereas the garnets are andraditic in outer zones, but are grossularitic in the central zone. This indicates a reverse relationship of Fe-contents between pyroxene and garnet across the exoskarn zones. Pyroxenoids are lacking in wollastonite but are dominated by pyroxmangite, rhodonite and bustamite, indicating a Mn-rich nature in bulk chemistry. Pseudomorphic fluorite after garnet occurs abundantly reflecting a fluorine-enhanced evidence of the skarn-forming fluids. Epidote contains 0.19-0.25mole fraction of pistacite, and chlorite is Mn-rich but is Mg-poor. Sulfide mineralization took place with the most Fe-rich pyroxene rather than with garnet as indicated by the fact that the highest value of hedenbergite mole fraction occurs in the ore-bearing pyroxene zone. The Yeonhwa II ores are characterized by high zinc and low lead in metal grade, with minor quantity of copper content in almost constant grade. The hangingwall Wolgok and Seongok orebodies, that formed in a more open environment with respect to their local configurations of geologic setting, are more variable in metal grades and ratios, than are the footwall Wolgok orebodies formed in a more closed condition in a narrow interval of sedimentary beds.

  • PDF