کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8137539 | 1523546 | 2014 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Geomorphology and structural geology of Saturnalia Fossae and adjacent structures in the northern hemisphere of Vesta
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Geomorphology and structural geology of Saturnalia Fossae and adjacent structures in the northern hemisphere of Vesta Geomorphology and structural geology of Saturnalia Fossae and adjacent structures in the northern hemisphere of Vesta](/preview/png/8137539.png)
چکیده انگلیسی
Vesta is a unique, intermediate class of rocky body in the Solar System, between terrestrial planets and small asteroids, because of its size (average radius of â¼263Â km) and differentiation, with a crust, mantle and core. Vesta's low surface gravity (0.25Â m/s2) has led to the continual absence of a protective atmosphere and consequently impact cratering and impact-related processes are prevalent. Previous work has shown that the formation of the Rheasilvia impact basin induced the equatorial Divalia Fossae, whereas the formation of the Veneneia impact basin induced the northern Saturnalia Fossae. Expanding upon this earlier work, we conducted photogeologic mapping of the Saturnalia Fossae, adjacent structures and geomorphic units in two of Vesta's northern quadrangles: Caparronia and Domitia. Our work indicates that impact processes created and/or modified all mapped structures and geomorphic units. The mapped units, ordered from oldest to youngest age based mainly on cross-cutting relationships, are: (1) Vestalia Terra unit, (2) cratered highlands unit, (3) Saturnalia Fossae trough unit, (4) Saturnalia Fossae cratered unit, (5) undifferentiated ejecta unit, (6) dark lobate unit, (7) dark crater ray unit and (8) lobate crater unit. The Saturnalia Fossae consist of five separate structures: Saturnalia Fossa A is the largest (maximum width of â¼43Â km) and is interpreted as a graben, whereas Saturnalia Fossa B-E are smaller (maximum width of â¼15Â km) and are interpreted as half grabens formed by synthetic faults. Smaller, second-order structures (maximum width of <1Â km) are distinguished from the Saturnalia Fossae, a first-order structure, by the use of the general descriptive term 'adjacent structures', which encompasses minor ridges, grooves and crater chains. For classification purposes, the general descriptive term 'minor ridges' characterizes ridges that are not part of the Saturnalia Fossae and are an order of magnitude smaller (maximum width of <1Â km vs. maximum width of â¼43Â km). Shear deformation resulting from the large-scale (diameter of <100Â km) Rheasilvia impact is proposed to form minor ridges (â¼2Â km to â¼25Â km in length), which are interpreted as the surface expression of thrust faults, as well as grooves (â¼3Â km to â¼25Â km in length) and pit crater chains (â¼1Â km to â¼25Â km in length), which are interpreted as the surface expression of extension fractures and/or dilational normal faults. Secondary crater material, ejected from small-scale and medium-scale impacts (diameters of <100Â km), are interpreted to form ejecta ray systems of grooves and crater chains by bouncing and scouring across the surface. Furthermore, seismic shaking, also resulting from small-scale and medium-scale impacts, is interpreted to form minor ridges because seismic shaking induces flow of regolith, which subsequently accumulates as minor ridges that are roughly parallel to the regional slope. In this work we expand upon the link between impact processes and structural features on Vesta by presenting findings of a photogeologic, structural mapping study which highlights how impact cratering and impact-related processes are expressed on this unique, intermediate Solar System body.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 244, December 2014, Pages 23-40
Journal: Icarus - Volume 244, December 2014, Pages 23-40
نویسندگان
Jennifer E.C. Scully, A. Yin, C.T. Russell, D.L. Buczkowski, D.A. Williams, D.T. Blewett, O. Ruesch, H. Hiesinger, L. Le Corre, C. Mercer, R.A. Yingst, W.B. Garry, R. Jaumann, T. Roatsch, F. Preusker, R.W. Gaskell, S.E. Schröder, E. Ammannito,