搜索到145篇“ THARSIS“的相关文章
Formation and modification of wrinkle ridges in the central Tharsis region of Mars as constrained by detailed geomorphological mapping and landsystem analysis
2023年
Wrinkle ridges are common landforms documented on all rocky planets and the Moon in the inner solar system.Despite the long research history,their formation mechanisms remain debated.A key unresolved issue is whether the wrinkle-ridge formation is related to igneous processes.This is because wrinkle ridges are mostly associated in space and possibly in time with the occurrence of flood-basalt volcanism in all cases in the inner solar system.To address this issue,we conducted geomorphological mapping,a topographic-data analysis,and a detailed landform and landsystem analysis of satellite images at a resolution of 25 cm/pixel to 6 m/pixel in the central Tharsis region of Mars.The main results of this work are in the form of(1)a regional geomorphological map at a resolution of 6 m/pixel and(2)a local geomorphological map at a resolution of 50 cm/pixel.Our work suggests the following older-to-younger sequence of geological events in the study area:(1)formation of a northeast-trending mountain range(i.e.,the Thaumasia plateau)along the eastern margin of the Tharsis rise that was created by the Himalayan-style crustal-scale thrusting;(2)coeval volcanic-plateau construction west of the thrusting-induced rising mountain range;(3)eastward-flowing lavas that were sourced from a volcanic plateau to the west terminated at the rising Thaumasia plateau to the east;(4)wrinkle-ridge development by decollement folding of recently emplaced warm,ductile volcanic-lava piles;(5)emplacement of a regionally extensive ice sheet over the central Tharsis region that produced extensive boulder-bearing materials,striated surfaces,and boulder-bearing dendritic-ridge networks possibly representing subglacial eskers;and(6)local deposition of highly concentrated glacial flours resulted in the formation of mantled terrain on plains between wrinkle ridges.Our work supports the early suggestion that the Tharsis wrinkle ridges were created by horizontal shortening induced by crustal-scale tectonic processes.In detail,however,the occurrence of flow-
An YinYingChi Wang
关键词:GLACIATION
火星Tharsis大火山岩省及其与五大连池火山的对比研究
火星是与地球具有最多相似性的内地行星,也是进行比较行星地质学研究最好的行星.近年来的大量探测活动,包括轨道器遥测和着陆器与漫游车的就位探测已获得大量数据.本文对火星Tharsis大火山岩省及其与五大连池火山进行对比研究,...
肖龙
关键词:行星地质学火星探测
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Iberan黄铁矿带的Tharsis矿山硫化物矿床的沉积构造
1995年
Tharsis矿区是Iberian黄铁矿带中最大的成矿中心之一。它包括了Iberian半岛西南的广大地区。对Tharsis矿山Filo Notvte硫化物矿床中的沉积构造进行了野外和显微镜下的研究。以内部构造为依据,把硫化矿床分为两类:(1)致密块状黄铁矿矿石;(2)具有沉积构造的黄铁矿石。在后一种类型中,已观察到若干沉积构造,例如:序粒层理、平行纹理、交错纹理及滑塌构造。
Yukin.,O
关键词:硫化物矿床
火星Thaumasia高原上具原始岩浆成分的岩墙:对Tharsis火山作用和水手大峡谷扩张的意义
我们利用热发射成像系统(Thermal Emission Imaging System:THEMIS),结构相机(Context Camera:CTX),高分辨率科学相机(High Resolution Imaging ...
黄俊C.S.EdwardsB.H.N.HorganP.R.ChristensenM.D.Kraft肖龙赵健楠
关键词:岩墙火山作用火星
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THARSIS-TRIGGERED FLOOD INUNDATIONS OF THE NORTHERN PLAINS OF MARS
Throughout the recorded history of Mars, liquid water has shaped its landscape into a number of distinct morph...
Alberto G. Fairen
Adenoma and advanced neoplasia detection rates increase from 45 years of age被引量:7
2019年
BACKGROUND Colonoscopy is considered a valid primary screening tool for colorectal cancer(CRC). The decreasing risk of CRC observed in patients undergoing colonoscopy is correlated with the adenoma detection rate(ADR). Due to the fact that screening programs usually start from the age of 50, very few data are available on the risk of adenoma between 40 and 49 years. However, the incidence of CRC is increasing in young populations and it is not uncommon in routine practice to detect adenomas or even advanced neoplasia during colonoscopy in patients under 50 years.AIM To compare the ADR and advanced neoplasia detection rate(ANDR) according to age in a large series of patients during routine colonoscopy.METHODS All consecutive patients who were scheduled for colonoscopy were included.Exclusion criteria were as follows: patients scheduled for partial colonoscopy or interventional colonoscopy(for stent insertion or stenosis dilation).Colonoscopies were performed in our unit by a team of 30 gastroenterologists in2016. We determined the ADR and ANDR in each age group in the whole population and in the population with an average risk of CRC(excluding patients with personal or family history of advanced adenoma or cancer).RESULTS6027 colonoscopies were performed in patients with a median age of 57 years(range, 15-96). The ADR and ANDR were 28.6% and 9.7%, respectively, in the whole population. When comparing patients aged 40-44(n = 382) and 45-49 years (n = 515), a strong increase in all parameters from 45 years was observed, with the ADR rising from 9.7% in patients aged 40-44 to 21.2% between 45 and 49(P <0.001) and the ANDR increasing from 3.1% in patients aged 40-44 to 6.4% in those aged 45-49 years(P < 0.03). With regard to patients aged 50-54(n = 849), a statistically significant increase in the ADR and ANDR was not observed between patients aged 45-49 and those aged 50-54 years. In the population with an average risk of CRC, the ADR and ANDR were still significantly higher in patients aged 45-49 compared with those
David KarsentiGaelle TharsisPascal BurtinFranck VeneziaGilles TordjmanAgnès GilletJoelle SamamaKarine Nahon-UzanPhilippe CattanMaryan Cavicchi
关键词:COLORECTALSCREENINGADENOMACOLONOSCOPYCOHORT
Compositional evolution of lava plains in the Syria-Thaumasia Block,Mars
2014年
Tharsis is the most prominent volcanic province on Mars,yet the compositions of lava flows and how composition relates to the development of Tharsis are poorly known.Most of Tharsis is covered with air-fall dust,which inhibits spectroscopic determination of lava mineralogy.The Syria-Thaumasia Block(STB)is a complex tectono-volcanic province closely related to the Tharsis bulge.The lava plains of STB have different emplacement ages,which provide an opportunity to examine whether magma composition changed with the evolution of Tharsis.In this study,we assessed the lava plains using Thermal Emission Spectrometer(TES)data.Using derived physical properties,we targeted dust-free regions from four different-aged geological units'surfaces and determined the mineralogical composition by modeling the average TES surface spectrum from each of the four surfaces.All units have similar mineralogy but the younger two units have elevated abundance of high-SiO2phases.The spatial distribution of wrinkle ridges indicates lava plains of unit HNr(older ridged plains material)and Hr(younger ridged plains material)were emplaced before the rise of Tharsis,whereas Hsl(flows of lower member)and Hsu(upper member)were emplaced after Tharsis uplift was initiated.We show that the magma composition differed in the lava plains of STB after the uplift of Tharsis.This study further characterizes early martian magma composition and evolution.
HUANG JunXIAO Long
关键词:THARSISMARS
Estimation of the thickness of the Tharsis lava flows and implications for the nature of the topography of the Tharsis plateau
An attempt to estimate the thickness of the volcanics which cover the large part of the Tharsis region is repo...
Plescia, J. B.;Saunders, R. S.
Ancient and modern slopes in the Tharsis region of Mars
Ancient slope directions in the Martian Tharsis region are compared with new earth-based radar observations in...
Mouginis-Mark, P. J.;Zisk, S. H.;Downs, G. S.
The Tharsis Montes, Mars - Comparison of volcanic and modified landforms
The three Tharsis Montes shield volcanos, Arsia Mons, Pavonis Mons, and Ascraeus Mons, have broad similarities...
Zimbelman, James R.;Edgett, Kenneth S.

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肖龙
作品数:126被引量:1,675H指数:22
供职机构:中国地质大学地球科学学院
研究主题:地球化学 地幔柱 月球 火星 西准噶尔