地质专业英语翻译.doc

专业英语翻译

文章题目：《Facies Associations,Paleoenvironment, and Base-Level Changes in the Upper上 Cretaceous Wahweap Formation, Utah, U.S.A.》
文章出处：《Geosphere》
文章作者：Zubair A. Jinnah1 and Eric M. Roberts2

Facies Associations, Paleoenvironment, and Base-Level Changes in the Upper上 Cretaceous
Wahweap Formation, Utah, U.S.A.

The Wahweap Formation is an ~ 400-m-thick succession of fluvial and estuarine channel sandstones and floodbasin mudstones divided into lower, middle, upper, and capping sandstone members. Facies analysis of the Wahweap Formation on the Kaiparowits Plateau reveals the presence of ten facies associations grouped into channel and floodbasin deposits. Facies associations (FAs) from channels include: (1) single-story and (2) multistory lenticular sandstone bodies, (3) major tabular sandstone bodies, (4) gravel bedforms, (5) low-angle heterolithic cross-strata, and (10) lenticular mudrock, whereas floodbasin facies associations include: (6) minor tabular sandstone bodies, (7) lenticular interlaminated sandstone and mudrock, (8) inclined interbedded sandstone and mudrock, and (9) laterally extensive mudrock.
The lower and middle members are dominated by floodbasin facies associations. The lower member consists dominantly of FA 8, interpreted as proximal floodbasin deposits including levees and pond margins, and is capped by a persistent horizon of FA 3, interpreted as amalgamated channel deposits. FAs 4 and 6 are also present in the lower member. The middle member consists dominantly of FA 9, interpreted as distal floodbasin deposits including swamp, oxbow-lake, and waterlogged-soil horizons. FAs 1, 2, 5, 6, 7, 8, and 10 are present in the middle member as well, which together are interpreted as evidence of suspended-load channels. The upper member is sandstone-dominated and consists of FAs 1, 2, 3, 5, 7, and 8. FAs 5 and 7, which occur at the base of the upper member, are interpreted as tidally influenced channels and suggest a marine incursion during deposition of the upper member. The capping sandstone is characterized by FAs 3, 4, and 6, and is interpreted to represent a major change in depositional environment, from meandering river systems in the lower three members to a low-accommodation, braided river system.
Improved age constraints on the Wahweap Formation indicate that the middle and upper members were deposited during the eustatic Claggett transgression (T8 of Kauffman 1977) in the adjacent Western Interior Seaway. Additionally, facies analysis of the Wahweap Formation has revealed an increase in both the sand:mud ratio and the degree of sandstone amalgamation from the upper part of the middle member to the base of the capping sandstone, suggesting a gradual reduction in generation of accommodation in the basin. Following recent alluvial sequence stratigraphic models, the middle member is interpreted as the isolated fluvial facies tract, while the upper member represents the tidally influenced and highstand facies tracts. Maximum transgression occurred during deposition of the lowest part of the upper member, synchronous with the putatively eustatic Claggett highstand in other parts of the Western Interior Basin. The sequence boundary is placed at the base of the overlying capping sandstone member, diagnosed by a major shift in petrography and paleocurrent direction, as well as up to 4 m of fluvial incision into the underlying upper member. The capping sandstone member is interpreted as the amalgamated fluvial facies tract, and the sequence boundary at the base of the capping sandstone is regarded as tectonically induced. Improved geochronology in the formation now permits high-resolution correlation with marine units to the east and along-strike correlation with contemporaneous alluvial units up and down the western margin of the Western Interior Basin.

Facies Associations相关联, Paleoenvironment海, and Base-Level基准面
Changes in the Upper上 Cretaceous白垩纪
Wahweap Formation形成
, Utah犹他州
, U.S.A.
Wahweap的形成是一个~ 400米-thick连续的河流河口通道的砂岩及floodbasin分为下部砂岩、中、上层和盖砂岩的成员。相分析的Wahweap形成高原的存在Kaiparowits揭示十相关联floodbasin分为通道和存款。协会(FAs)相从通道单元包括:(1)和(2)透镜状砂岩体北侧,(3)主要表格砂岩体碎石bedforms;(4),(5)低角heterolithic阶层,(10)透镜崩塌,而floodbasin相协会包括:(6)小表格砂岩体;(7)透镜状砂岩和层间崩塌,(8)斜夹砂岩和崩塌,(9)外侧广泛崩塌。
中、下成员主要由floodbasin相关联。较低的成员由足总8日占优势解释为包括堤和近端floodbasin存款池塘的利润率,是一个持续的地平线上,解释为合并足总3通道存款。FAs 4和6同样出现在较低的成员。中间的成员由足总9日占优势解释为远端floodbasin存款包括沼泽、oxbow-lake,waterlogged-soil视野。FAs第1、2、5、6、7、8、10成员出现在中间,在一起的证据suspended-load解释渠道。上面的成员,由sandstone-dominated FAs 1、2、3、5、7、8。FAs 5分和7分,其中发生在该基地的上部是解释为会员,并指出了潮汐地被影响海洋入侵通道在沉积上成员。砂岩的特点是限制FAs 3、4、6号,是解释为代表发生了重大变化,从曲流河沉积环境系统处于较低的三个成员,一个low-accommodation辫状河系统。
改进的年龄的限制Wahweap形成表明,中层和上层成员在eustatic Claggett沉积(T8的罪过Kauffman 1977)相邻西方内部产生。此外,相分析形成的Wahweap透露增加两个砂泥比和程度,上部砂岩融合中成员基地的限制,这表明逐渐减少砂岩在一代的住宿在盆子里。最近的冲积层序地层模式后,中间的成员被解释为孤立的河流相沉积的系统,而上部会员代表和高位域潮汐地被影响相。最大海侵发生在沉积最低的上层部分成员,同步与拍摄Claggett高位eustatic国内其他地区的西方室内盆。边界被放置在序列的基础上覆盖砂岩成员,一个主要的转变为在岩石和运用地层厚度方向,以及4米高的流水下切上潜在的会员。盖砂岩的成员被解释为合并的河流相沉积的道,边界和序列在该基地的盖砂岩作为构造诱发。改进的同位素地质年代学形成现在允许高分辨率相关与海洋单位东部和along-strike相关性,而与同时代的冲积单位的西缘上下西方室内盆。

Wahweap（美国地名）结构是400米厚的，一个由连续的河流、河口的河道砂岩和洪水流域泥岩组成的岩土结构。它可分为下层、中层、上层以及顶层砂岩。对Kaiparowits高地上的Wahweap结构的分相分析揭示了在河道砂岩和洪水流域沉积存在十个相的组合结构。这十个相组分包括：河道砂岩的(1)单层 ，(2)多层透镜状砂岩体，(3)大板状砂岩体，(4)河床砂砾，(5)低角度不规整交错地层，(10)透镜状泥砂；以及洪水流域泥岩的(6)小板状砂岩体，（7）透镜状夹层砂岩和泥砂，（8）倾斜状夹层砂岩和泥砂，和（9）侧向延伸泥砂。
下层和中层砂岩主要成分是洪水流域泥岩相。下层成分主要是相组分8，也被称作近似洪水流域沉积，例如河堤和池塘边缘区域，它被稳固的相组分3层覆盖，这就是合并河道沉积。相组分4和6也出现在下层成分区。中层的主要成分是俗称 洪水流域末端沉积的相组分9，包括沼泽区，U型湖和渍水土层。相组分1、2、5、6、7、8和10都出现中层区出现，这是可被视为悬浮泥砂河道的证据。上层的主要成分是砂岩，它由相组分1、2、3、5、7和8组成。相组分5和7出现在上层区的底部，它们被视作受潮汐影响的河道，暗示了在上层成分沉积过程中有海水倒灌现象发生。顶部砂岩有相组分3、4和6，它是沉积环境发生大改变的一个象征, 从最初处于下面三层（下、中、上层）的蜿蜒河流系统，一直到低可容纳空间的分叉河流系统

改进对Wahweap形成年龄的限制表明，中部和上部成员在海平面Claggett侵在相邻的西部内陆海道（考夫曼1977年的T8）交存。此外，相的Wahweap形成分析显示，在两个砂增加：泥比和砂岩合并从中间成员的上限砂岩基地上部程度，预示着在住宿一代逐渐减少盆地。在最近的冲积层序地层模型，中间的成员被解释为孤立道河流相，而上部的成员代表了潮汐影响和高位相大片。最大海侵过程中出现的上层成员，这种公认海平面Claggett在西部内陆盆地其他地区高水位同步的最低部分沉积。该序列的边界被放置在覆盖砂岩成员由在岩石学和古水流方向的重大转变，以及成底层的上段为4米的河流切口诊断的基础。加盖砂岩成员被解释为合并后道河流相，以及在封盖砂岩碱基序列的边界被视为构造引起的。改进的年代学的形成与现在允许单位到东部海洋高分辨率关联和沿罢工与同期相关单位和冲积下来的西部内陆盆地西缘。