地震研究

文山—麻栗坡断裂北段第四纪活动特征研究^*

周青云¹,张沛全²,李鉴林¹,余建强¹

(1.云南省地震局,云南昆明650041; 2.广西壮族自治区地震局,广西南宁530200)

Research on Characteristics of Late Quaternary Activity of the North Wenshan-Malipo Fault

ZHOU Qingyun¹, ZHANG Peiquan², LI Jianlin²,YU Jianqiang¹

(1.Earthquake Administration of Yunnan Province, Kunming 650041, Yunnan, China)(2.Seismological Bureau of Guangxi Zhuang Autonomous Region, Nanning 530022, Guangxi, China)

Keywords：Wenshan-Malipo Fault; aero photogrammetry interpretation; tectonic geomorphology; terrace

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利用航片解译结果并结合野外地质调查,对文山—麻栗坡断裂(简称文麻断裂)北段的地震地质特征进行研究。解译结果显示,断裂沿线活动构造地貌清晰,主要表现为断层陡坎、断陷盆地、水系同步右旋位错等; 影像上线性特征明显而平直,构成(文山)盆地与基岩山地的界线。野外地震地质调查结果显示,该断裂在热水寨切错了T₂阶地堆积,被错地层光释光(OSL)测年结果为(18.1±0.5)ka B.P.,文山盆地北5 km处同样断错T₂阶地堆积,其 ¹⁴C年龄为(15.67±0.05)ka B.P.。以上结果表明,该断裂在晚更新世有过明显的活动迹象,运动性质为右旋走滑兼正断。

Combined the new interpretation of aerial photos with the field geological survey, we investigated the seismic geological characteristic of the northern section of Wenshan-Malipo Fault(Wen-Ma Fault). The interpretation results showed that there is the clear active tectonic geomorphology along the fault, which was mainly manifested as fault scarps, fault basin, river system synchronous dextral dislocations etc.. The linear features on the image are very clear and straight, forming the boundaries between Wenshan basin and bedrock mountains. According to filed seismic geological survey results, we find that the fault in Reshuizhai disrupts T₂ accumulation terrace, and the Optically Stimulated Luminescence(OSL)dating of the disrupted strata suggests an age of(18.1±0.5)ka B.P.. While in the area of the distace of 5 km to the north of Wenshan basin, the radiocarbon dating(¹⁴C)of the disrupted T₂ accumulation terrace shows an age of(15.67±0.05)ka B.P.. In conclusion, the Wen-Ma Fault has clear signs of activities in the late Pleistocene, which is dominated by dextral strike slip with normal slip component.

引言
1 航片线性特征解译
2 地震地质特征
3 讨论与结论

图1 文山—麻栗坡断裂及构造解译图<br/>Fig.1 Distribution of Wenshan-Malipo Fault and its tectonic interpretation map

图1 文山—麻栗坡断裂及构造解译图
Fig.1 Distribution of Wenshan-Malipo Fault and its tectonic interpretation map

图2 文山盆地及其以北航片的构造地貌解译<br/>(a)区域航片解译图;(b)文山盆地解译图;(c)白沙坡北解译图;(d)解译点位置示意图<br/>Fig.2 Interpretations for tectonic geomorphology of aero photograph of Wenshan basin and its north area (a)regional aerial photograph interpretation;(b)interpretations of Wenshan basin;(c)interpretations of northern Baishapo;(d)sketch map of the location of interpretated point

图2 文山盆地及其以北航片的构造地貌解译
(a)区域航片解译图;(b)文山盆地解译图;(c)白沙坡北解译图;(d)解译点位置示意图
Fig.2 Interpretations for tectonic geomorphology of aero photograph of Wenshan basin and its north area (a)regional aerial photograph interpretation;(b)interpretations of Wenshan basin;(c)interpretations of northern Baishapo;(d)sketch map of the location of interpretated point

图3 白沙坡以南断层槽地照片(镜像S)<br/>Fig.3 Photo of fault trough at the south area of Baishapo(mirror at S)

图3 白沙坡以南断层槽地照片(镜像S)
Fig.3 Photo of fault trough at the south area of Baishapo(mirror at S)

图4 马塘北东梳状水系地貌解译(a)及其位置示意图(b)<br/>Fig.4 Interpretation of comb like drainage geomorphology at the northeast area of Matang(a)and sketch map of its location(b)

图4 马塘北东梳状水系地貌解译(a)及其位置示意图(b)
Fig.4 Interpretation of comb like drainage geomorphology at the northeast area of Matang(a)and sketch map of its location(b)

图5 梳状水系两盘高差照片(a)及北西盘顶部沉积物质照片(b)<br/>Fig.5 Photos of the altitude difference of two plates of the comb like drainage (a)and sediment at the top of northwest plate(b)

图5 梳状水系两盘高差照片(a)及北西盘顶部沉积物质照片(b)
Fig.5 Photos of the altitude difference of two plates of the comb like drainage (a)and sediment at the top of northwest plate(b)

图6 平坝寨附近航片的构造地貌解译图(a)、陡坎发育地貌图(b)及位置示意图(c)<br/>Fig.6 Interpretations for tectonic geomorphology of aero photograph(a), geomorphologic map of scarp (b)and the sketch map of its location(c)at Pingbazhai and its adjacent area

图6 平坝寨附近航片的构造地貌解译图(a)、陡坎发育地貌图(b)及位置示意图(c)
Fig.6 Interpretations for tectonic geomorphology of aero photograph(a), geomorphologic map of scarp (b)and the sketch map of its location(c)at Pingbazhai and its adjacent area

图7 平坝寨南东的断层陡坎及挤压脊(a)、炭化带(b)、洪积扇(c)照片<br/>Fig.7 Photos of fault trough and extrusion ridge(a)、carbonization zone(b)、alluvial fan(c)at southeast area of Pingbazhai

图7 平坝寨南东的断层陡坎及挤压脊(a)、炭化带(b)、洪积扇(c)照片
Fig.7 Photos of fault trough and extrusion ridge(a)、carbonization zone(b)、alluvial fan(c)at southeast area of Pingbazhai

图8 蚂蟥塘南东约1 km处断层照片(a、b)、擦痕照片(c)及断层剖面图(d)<br/>Fig.8 Photos of fault(a, b), scratch(c), and the sectional drawing of the fault (d)in the area of the distance of 1 km from southeast of Mahuangtang

图8 蚂蟥塘南东约1 km处断层照片(a、b)、擦痕照片(c)及断层剖面图(d)
Fig.8 Photos of fault(a, b), scratch(c), and the sectional drawing of the fault (d)in the area of the distance of 1 km from southeast of Mahuangtang

图9 热水寨及附近地貌图<br/>Fig.9 Geomorphology at Reshuizhai and its adjacent area

图9 热水寨及附近地貌图
Fig.9 Geomorphology at Reshuizhai and its adjacent area

图10 热水寨以南断层槽地<br/>Fig.10 Fault trough in the south area of Reshuizhai

图10 热水寨以南断层槽地
Fig.10 Fault trough in the south area of Reshuizhai

图11 热水寨断层照片(a)及剖面图(b)<br/>Fig.11 Photo of the fault zone at Reshuizhai(a)and its sectional drawing(b)

图11 热水寨断层照片(a)及剖面图(b)
Fig.11 Photo of the fault zone at Reshuizhai(a)and its sectional drawing(b)

图12 热水寨断层下盘擦痕照片(镜像NE)<br/>Fig.12 Photo of scratch of the footwall fault at Reshuizhai(mirror at NE)

图12 热水寨断层下盘擦痕照片(镜像NE)
Fig.12 Photo of scratch of the footwall fault at Reshuizhai(mirror at NE)

图13 热水寨附近断层照片(a)及剖面图(b)<br/>Fig.13 Photo of the fault zone at Reshuizhai and its adjacent(a)and its sectional drawing(b)

图13 热水寨附近断层照片(a)及剖面图(b)
Fig.13 Photo of the fault zone at Reshuizhai and its adjacent(a)and its sectional drawing(b)

图14 热水寨北1 km附近断层照片(a)及剖面图(b)<br/>Fig.14 Photo of the fault zone in the area of the distance of 1 km from the north of Reshuizhai(a) and its sectional drawing(b)

图14 热水寨北1 km附近断层照片(a)及剖面图(b)
Fig.14 Photo of the fault zone in the area of the distance of 1 km from the north of Reshuizhai(a) and its sectional drawing(b)

图15 洪水塘南东2 km水系位错照片(a)及卫星影像(b)<br/>Fig.15 Photo of drainage dialocation in the area of the distance of 2 km from the south east of Hongshuitang (a)and its satellite image(b)

图15 洪水塘南东2 km水系位错照片(a)及卫星影像(b)
Fig.15 Photo of drainage dialocation in the area of the distance of 2 km from the south east of Hongshuitang (a)and its satellite image(b)

图16 平远镇NE约800 m处断层照片(a)及剖面图(b)<br/>Fig.16 Photo of the fault zone in the area of the distance of 800 m from the northeast of Pingyuanzhen(a)and its sectional drawing(b)

图16 平远镇NE约800 m处断层照片(a)及剖面图(b)
Fig.16 Photo of the fault zone in the area of the distance of 800 m from the northeast of Pingyuanzhen(a)and its sectional drawing(b)