Folds--Offshore Scott Creek, California

This part of DS 781 presents data for the folds for the geologic and geomorphic map of the Offshore of Scott Creek map area, California. The vector data file is included in "Folds_OffshoreScottCreek.zip," which is accessible from http://dx.doi.org/10.5066/F7CJ8BJW. The offshore of Scott Creek map area straddles the right-lateral San Gregorio Fault Zone, an important structure in the distributed transform boundary between the North American and Pacific plates (see, for example, Dickinson and others, 2005). Regionally, this fault is part of a system that occurs predominantly in the offshore for about 400 km from Point Conception in the south (where it is known as the Hosgri fault; Johnson and Watt, 2012) to Bolinas and Point Reyes in the north (Bruns and others, 2002; Ryan and others, 2008). The San Gregorio Fault in the map area is part of a 90-km-long offshore segment that extends from Point Sur on the south, across outer Monterey Bay to Point Año Nuevo (just one kilometer north of the map area) on the north (Weber and Lajoie, 1980; Brabb, 1997; Wagner and others, 2002). Offshore parts of this fault system are identified on seismic-reflection data based on abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. In this map area, the San Gregorio Fault forms a distributed about 2-km-wide shear zone that includes two main faults. The nearshore eastern part of the zone, which includes the Coastways Fault, partly coincides with a prominent bathymetric lineament on the outer flank of nearshore bedrock outcrops between Waddell Creek and Davenport. The western part of the zone, which includes the Frijoles Fault, cuts across the flat, sediment-covered shelf. Cumulative lateral slip on San Gregorio Fault Zone in this region is thought to range from 4 to 10 mm/yr (Weber, 1994). McCulloch (1987) considered the San Gregorio Fault Zone the eastern margin of the Outer Santa Cruz Basin (fig. 8-1). Farther offshore, outside California's State Waters but within the map area, this basin is cut by the northwest-trending Ascension Fault (Greene and others, 2002; U.S. Geological Survey and California Geological Survey, 2010). References Cited Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97-489, 1:62,500. Bruns, T.R., Cooper, A.K., Carlson, P.R., and McCulloch, D.S., 2002, Structure of the submerged San Andreas and San Gregorio Fault zones in the Gulf of Farallones as inferred from high-resolution seismic-reflection data, in Parsons, T. (ed.), Crustal structure of the coastal and marine San Francisco Bay region, California: U.S. Geological Survey Professional Paper 1658, p. 77-117. Dickinson, W.R., Ducea, M., Rosenberg, L.I., Greene, H.G., Graham, S.A., Clark, J.C., Weber, G.E., Kidder, S., Ernst, W.G., and Brabb, E.E., 2005, Net dextral slip, Neogene San Gregorio-Hosgri fault zone, coastal California - Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., Maher, N.M., and Paull, C.K., 2002, Physiography of the Monterey Bay National Marine Sanctuary and implications about continental margin development: Marine Geology, v. 181, p. 55-82. Johnson, S.Y., and Watt, J.T., 2012, Influence of fault trend, bends, and convergence on shallow structure and geomorphology of the Hosgri strike-slip fault, offshore Central California: Geosphere, v. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401. Ryan, H.F., Parsons, T., and Sliter, R.W., 2008. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California: Tectonphysics, v. 429, p. 209-224. Weber, G.E., and LaJoie, K.R., 1980, Map of Quaternary faulting along the San Gregorio fault zone, San Mateo and Santa Cruz counties, California: US Geological Survey Open-File Report 80-907. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.本数据集（DS 781）的该部分提供了加利福尼亚州斯科特溪近海地图区域地质与地貌图所需的褶皱（folds）相关数据。矢量数据文件收录于"Folds_OffshoreScottCreek.zip"，可通过http://dx.doi.org/10.5066/F7CJ8BJW获取。 斯科特溪近海地图区域横跨右旋圣格雷戈里奥断裂带（San Gregorio Fault Zone），该断裂带是北美板块与太平洋板块间离散转换边界的重要构造（例如可参考Dickinson等人2005年的研究）。从区域尺度来看，该断裂隶属于一条主要分布于近海的断裂系统，其延伸范围南起康塞普申角（此处该断裂被称为霍斯格里断裂；Johnson与Watt, 2012），北至博利纳斯和雷耶斯角，全长约400千米（Bruns等人, 2002; Ryan等人, 2008）。本地图区域内的圣格雷戈里奥断裂是一段长90千米的近海断裂段的一部分，该断裂段南起苏尔角，向北横穿蒙特雷湾外海，直至阿尼奥新诺角（位于本地图区域以北仅1千米处）（Weber与Lajoie, 1980; Brabb, 1997; Wagner等人, 2002）。该断裂系统的近海部分可通过地震反射数据识别，识别依据为反射波的突然截断或弯曲，以及（或）具有不同地震参数的反射波组的并置。在本地图区域内，圣格雷戈里奥断裂形成了一个宽约2千米的离散剪切带，包含两条主要断裂。该剪切带的近岸东段包含库斯特韦斯断裂（Coastways Fault），其部分区域与瓦德尔溪与达文波特之间近岸基岩露头外侧的一条显著水深线理重合。剪切带的西段包含弗里霍莱斯断裂（Frijoles Fault），横穿平坦的沉积覆盖陆架。该区域圣格雷戈里奥断裂带的累计侧向滑动速率被认为介于4至10毫米/年之间（Weber, 1994）。 McCulloch（1987）将圣格雷戈里奥断裂带视为外圣克鲁斯盆地的东界（图8-1）。在更远的近海区域，即加州州立水域之外但处于本地图区域内，该盆地被北西向的阿森松断裂（Ascension Fault）切断（Greene等人, 2002; 美国地质调查局与加州地质调查局, 2010）。 参考文献 Brabb, E.E., 1997，《加利福尼亚州圣克鲁斯县地质图：数字数据集》，美国地质调查局（US Geological Survey）公开文件报告97-489，比例尺1:62,500。 Bruns, T.R.、Cooper, A.K.、Carlson, P.R. 与 McCulloch, D.S., 2002，《基于高分辨率地震反射数据推断的法拉隆湾水下圣安德烈亚斯与圣格雷戈里奥断裂带构造》，收录于Parsons, T. 主编的《加利福尼亚州旧金山湾沿岸及海域地壳结构》：美国地质调查局（US Geological Survey）专业论文1658，第77-117页。 Dickinson, W.R. 等，2005，《加利福尼亚沿岸新近纪圣格雷戈里奥-霍斯格里断裂带的右旋净滑动：地质证据与构造意义》，美国地质学会（Geological Society of America）专刊391，共43页。 Greene, H.G.、Maher, N.M. 与 Paull, C.K., 2002，《蒙特雷湾国家海洋保护区地貌及其对大陆边缘演化的指示意义》，《海洋地质学（Marine Geology）》，第181卷，第55-82页。 Johnson, S.Y. 与 Watt, J.T., 2012，《断裂走向、弯曲与汇聚对加州中部近海霍斯格里走滑断裂浅层构造与地貌的影响》，《Geosphere》，第v.卷（原文未完整刊载）。 McCulloch, D.S., 1987，《加州中部近海区域地质与油气潜力》，收录于Scholl, D.W.、Grantz, A. 与 Vedder, J.G. 主编的《北美西部大陆边缘及邻近海域（波弗特海至下加利福尼亚）地质与资源潜力》：美国得克萨斯州休斯敦，环太平洋能源与矿产资源委员会（Circum-Pacific Council for Energy and Mineral Resources）地球科学系列，第6卷，第353-401页。 Ryan, H.F.、Parsons, T. 与 Sliter, R.W., 2008，《加利福尼亚州旧金山近海圣安德烈亚斯断裂带相关的垂直构造变形》，《构造物理学报（Tectonophysics）》，第429卷，第209-224页。 Weber, G.E. 与 LaJoie, K.R., 1980，《加利福尼亚州圣马特奥县与圣克鲁斯县圣格雷戈里奥断裂带第四纪断裂分布图》，美国地质调查局（US Geological Survey）公开文件报告80-907。 Wagner, D.L.、Greene, H.G.、Saucedo, G.J. 与 Pridmore, C.L., 2002，《加利福尼亚州蒙特雷30′×60′图幅及邻近区域地质图》，加州地质调查局区域地质图系列，比例尺1:100,000。