| 重矿物分析识别浊积体的沉积作用——日本中部Niigata弧后含油盆地新第三纪浊积砂岩实例研究(英文) |
| |
| 摘 要： | 沉积于中中新世到上新世的浊积砂体是第三纪Niigata弧后盆地的主要油气储层之一 ,该盆地是日本列岛最富产石油的盆地。我们对这些浊积砂体的重矿物进行了详细和系统地分析。首先 ,作者展示了将重矿物分析和沉积作用分析相结合 ,从而得出有关沉积过程的全新观点的实例。沿着位于盆地东缘的上新世早期的浊积砂岩体的垂向和横向取样分析表明 ,砂体东半部重矿物的成分和西半部重矿物的成分不同。重矿物和沉积分析结果表明 ,发育在东半部的浅海陆架浊积砂岩和发育在西半部的深海水下浊积体在上新世早期是相互叠置的。其次 ,作者检验了用重矿物成分作为指标来表征某个特定浊积体的有效性。为此目的特选重位于Ni igata盆地中部的许多浊积砂岩分析研究 ,得出以下结论。 ( 1)基于主要重矿物 ,比如蛋白石、普通角闪石、紫苏辉石和普通辉石的定量综合分析 ,至少可将研究区的浊积砂岩划分为 6种类型 ;( 2 )一个组或段的浊积砂岩包括一种类型或紧密相关的两种类型 ;( 3)研究区不同的组或段通常由不同的重矿物组成构成 ,不同的物源或相同物源下不同的地质事件 (例如火山活动开始期 )可能是这种差异的原因。重矿物分析不仅可作为有价值的常规手段估计物源方向 ,而且可同其他的沉积资料结合来解析沉积过程 ,估计几个相邻
|
| 关 键 词： | 重矿物分析 沉积过程 浊积体 新第三纪 弧后盆地 日本中部 |
NEW APPLICATION OF HEAVY MINERAL ANALYSIS TO DISCLOSE THE SEDIMENTARY PROCESS OF EACH TURBIDITE SANDSTONE BODY AND TO IDENTIFY INDIVIDUAL TURBIDITE SANDSTONE BODIES--CASE STUDIES ON NEOGENE TURBIDITE SANDSTONES IN THE NIIGATA BACKARC OIL BASIN, CENTRAL JAPAN |
| |
| Authors: | Shuichi Tokuhashi Christopher M Agyingi |
| |
| Abstract: | Many turbidite sandstone bodies, deposited during the Middle Miocene to Pliocene, are distributed and form one of major reservoirs for oil and gas in the Tertiary Niigata backarc sedimentary basin, the most productive oil basin in the Japanese Islands. We conducted detailed and systematic heavy mineral analysis for these turbidite sandstone bodies with following purposes and results.Firstly, the authors show a typical case study that the positive combination of heavy mineral analysis with sedimentological analysis leads to a completely different idea on the sedimentary process. Detailed vertical and lateral heavy mineral analysis of the early Pliocene turbidite sandstone body, located at the eastern margin of the basin, disclosed that heavy mineral composition of the turbidite sandstones in the eastern half of the body are completely different from that in the western half of the body. The results of heavy mineral and sedimentological analysis convinced that two kinds of turbidite sandstones, shallow-marine shelf turbidite sandstones in the eastern half and deep-marine submarine-fan turbidite sandstones in the western half, were juxtaposed in the area during the early Pliocene age. Secondly, the authors verify the effectiveness of heavy mineral composition as useful indicators to characterize the individual turbidite bodies which occupy the specific spaces with specific formation names or member names. Many turbidite sandstones located in the middle part of the Niigata basin has been selected for this purpose and resulted in the following conclusions. (1) The turbidite sandstones in the study area can be classified at least into six types based on the combination of the quantitatively major heavy minerals such as opaque minerals, hornblende, hypersthene, and augite. (2) The turbidite sandstones of one formation or one member are represented by one type or closely related two types. (3) The different formations or members in the study area are often composed of the different heavy mineral composition. The different provenance or the different geologic event (e.g. the beginning of volcanic activities) at the same provenance may be suggested as a cause of the difference.As a conclusion, the heavy mineral analysis is valuable not only as a conventional tool to estimate the provenance, but also as a strong measure to disclose their sedimentary process in combination with other sedimentary data, to estimate the original relationship of several sandstone bodies neighboring each other , and to predict the three-dimensional extents of surface and subsurface turbidite sandstone bodies. |
| |
| Keywords: | heavy mineral analysis sedimentary process turbidite sandstone body Neogene the Niigata backarc oil basin central Japan |
| 本文献已被 万方数据 等数据库收录！ |
|
