Abstract
摘要:本計畫為執行中央地質調查所推動之4年期「臺灣東北海域礦產資源潛能調查-震測及地熱流調查研究」工作,以震測與地熱流調查在臺灣東北海域南沖繩海槽進行金屬礦產開發潛能之調查與探勘研究,一以了解東北海域受海底火山活動產生的熱液換質作用是否亦有金屬硫化礦物的資源潛能,二則以震測與地熱流調查資料進而討論南沖繩海槽的地質背景與地體構造形貌,來推測地質活動作用在東北海域金屬礦產生成中所扮演的角色。本計畫包含總計畫與三個分項計畫,由「總計畫與礦產屬性資料庫」負責整個計畫之統整、規劃與協調工作,並且維護與更新東北海域礦產資源調查成果資料庫及資訊網,以達到調查成果資料保存的目的。
另由於本年度為四年期計畫的第四年,本(108)年度工作也將會彙整過去三年在調查區域A、B兩區的各項工作收集成果,整編已調查區域的區域地形、構造及重要調查站位的分布圖,並將協助下列三個分項計畫工作之進行:
(1)反射震測與海底回聲剖面調查研究:本年度計畫上半年重點工作,除將持續對105至107年收集之資料進行進一步處理、分析與解釋工作,包含了多頻道反射震測、海床回聲剖面以及EK60聲納資料,也會於臺灣東北海域規劃調查區域(C區)內進行2維多頻道反射震測與海底回聲剖面調查。下半年度則會對新收集的資料進行處理、分析、模擬與解釋,另外也會協助總計畫綜整本期計畫四年之成果,並繪製各項相關主題圖資,藉以瞭解此區域的地質背景,並完成第一期臺灣東北海域礦產資源潛能的評估工作。
(2)地熱流調查研究:本計畫過去3年為了瞭解臺灣東北海域沖繩海槽區域地熱流的分布,已階段性完成了第四與那國海丘(YK4-1)、棉花火山(MHV)以及石林隆堆(GLM)等區域的地熱流調查,並辨認出地熱流分布情形。同時也與地球化學團隊合作布放海床錨錠觀測系統,藉由分析溫度與地球化學的時序資料,解析出底水及淺部沉積物在熱液活動處的時序變化特徵。本年度預計持續將過去與新收集的地熱流資料加以整編,並規劃於南沖繩海槽西側(C區內)沿2維反射震測剖面進行地溫與地熱流之調查。本年度的工作除希望能對於大尺度的區域熱流能有更進一步的瞭解外,也將就海床錨錠觀測系統進行更深入的時序分析,透過與海洋物理及地球化學資料的對比,建立精查區域的熱液循環模式。另外,由於本年度為4年期計畫之最後一年,本團隊也將著重於協助總計畫分析過往重點站位的地熱流特性,並評估區域成礦潛能。上半年工作除將整編過往資料並協助總計畫分析重點站位外,並預計進行本年度的海上實測工作;下半年則會針對新收集之地熱流進行分析,並協助總計畫綜整本期資料及成果。
(3)地質構造、火成活動與沉積特徵研究:本年度分項計畫持續發展震測資料分析技術並進行地質解釋,以高解析震測資料精查南沖繩海槽第四與那國海丘鄰近區域。在震測資料分析技術方面,運用震測相分析、層序地層建立以及斷層活動度評估方法分析,對比鑽井ODP1202所提供的岩性、年代,推算近10萬年之地層、構造分布,以了解活動斷層以及近代沉積物堆積模式,並綜整地質構造、火成活動以及沉積特徵,建立臺灣東北海域地質模型。
Abstract: This proposal is the fourth year of the 4-year marine mineral resource investigation project of the Central Geological Survey entitled “Geological Investigation of Mineral Resource Potential in the Offshore Northeastern Taiwan: Seismic and Heat Flow Studies”. Seismic, heat flow and geothermal investigations will be carried out in the areas offshore northeastern Taiwan with 2 major goals: 1. To explore the mineral resource potential in the investigation area where submarine volcanic activities are prevailing; 2. To understand the relationships between geological/tectonic processes and mineral resources in the study area. To achieve these goals, a team has been formed that will carry out the field investigation and data analyses via one master project and 3 sub-projects. The master project is responsible for project planning and coordination among different sub-projects, also to develop and maintain a marine mineral resource database. The 3 sub-projects and their respective roles are: (1) Seismic reflection and chirp sonar investigations: multichannel 2D seismic reflection data and underway chirp sonar data in the proposed survey area (zone C) will be collected, processed and analyzed. This sub-project will also analyze and interpret seismic profiles and chirp sonar data collected in the past to understand further on volcanic activities, hydrothermal vents and structural and sedimentary processes. (2) Heat flow investigation: This sub-project aims to understand the heat flow distribution around the active hydrothermal circulation sites and their thermal charateristics. To better define the regional heat flow pattern, at least 4 heat flow sites in the western part of the South Okinawa Trough (zone C) will be investigated. This sub-project will also assist mooring temperature data analyses at active venting sites to fathom the features of hydrothermal circulation. The new data will be integrated with all the existing heat flow data in the investigation area to establish a regional heat flow pattern, and the prospective sites such as the GLM and the MHV will be evaluated indepth for then thermal aspects. (3) Stratigraphic analyses and sedimentary characteristics of the Southern Okinawa Trough: this sub-project tries to understand the evolution of tectonic architectures and sedimentary environments through interpretation of seismic reflection profiles, and tying to ODP well data in the study area. This sub-project will also build geological model of hydrothermal system with tectonic structures, volcanic activities and stratigraphy by summerizing geological and geophysical data.
Keyword(s)
礦產資源
臺灣東北海域
沖繩海槽
反射震測
地熱流量測
地溫梯度
地體構造
沉積環境
Mineral Resource
Offshore Northeastern Taiwan
Okinawa Trough
Seismic Investigation
Heat Flow Measurement
Geothermal Gradient
Mooring Observation System
Tectonic Framework
Sedimentary Environment