本研究對鑽採自宜蘭梅花湖湖積物岩芯MHL5-A進行環境磁學分析，其目的在探討台灣東北部宜蘭地區古氣候和古環境變遷情形。並盼對東亞季風系統之消長有進一步之了解。此項研究工作為中央研究院地球科學研究所主題計畫「亞洲古環境變遷」工作之一部份，該計畫目的在對東亞地區晚更新世以來古氣候及環境變遷作系統性的研究。
台灣位於東亞地區，氣候受來自西伯利亞高氣壓冬季季風和中國南方印度洋之低氣壓夏季季風交互影響，宜蘭在台灣東北部，因中央山脈阻擋西南季風，同時因喇叭狀的地形，地處迎風面，因此降雨現象顯著，主要為秋冬季因東北季風引起之豪大雨以及夏季颱風帶來大量降雨。本研究希望藉由分析包括磁感率、自然殘磁、逆磁滯殘磁、等溫殘磁等磁學參數，探討研究地區之古氣候和古環境變遷情形。
岩芯年代模式之建立係根據所選擇之七個C-14定年點，結果指出28.63公尺長之岩芯涵蓋過去5200多年來之訊息。而磁學參數(包括ARM、S-ratio及ARM/SIRM等)量測分析所得之結果指出，過去5200多年來之氣候變遷可劃分為20個時期，而氣候變化型態可歸納為四大類，分別如下：(1)約5300 ~ 5000、4850 ~ 4500、4300 ~ 4100、3700 ~ 2950、2500 ~ 2300 1950 ~ 1850、1700 ~ 1400、1100 ~ 700、500 ~ 400 yr BP: S-ratio變化較小，大部分介於0.9 ~ 1，以低氧化性磁鐵礦為主，氣候可能較穩定，乾濕變化不大，整體來說較潮濕；(2)約5000 ~ 4950、3850 ~ 3700、2950 ~ 2500、1850 ~ 1700 yr BP: S-ratio可低至小於0.8，高氧化性赤鐵礦也較多，磁性礦物粒度較粗，氣候可能較乾燥，一旦暴雨發生，會帶來較粗顆粒的磁性礦物和較多的赤鐵礦;(3)約4950 ~ 4850、4500 ~ 4300、4100 ~ 3850、2300 ~ 1950、1400 ~ 1100、700 ~ 500 yr BP: S-ratio值在0.8 ~ 1之間變化快速，磁性礦物的豐度也變化較其他時期快速，顯示當時氣候可能很不穩定，乾濕變化較其他時期快速，但乾燥的程度沒上一種氣候嚴重，當時可能降雨頻繁，降雨結束氣候又逐漸乾燥;(4)到近期400年來，乾濕變化大，但比上一種氣候的變化慢，而且似乎有100 ~ 150年之週期變動，與早期不同的地方是，細顆粒磁鐵礦較多，以及當具殘磁的磁性礦物較多，磁鐵礦粒度卻較細，此情形發生四次，或許是鄰近羅東溪水氾濫帶來細顆粒磁鐵礦;反之，較粗，而且順磁性物質較多，可能是乾燥時周圍岩屑崩落帶來順磁性物質。總而言之，宜蘭地區於晚全新世的氣候環境變化劇烈。

The goal of this research is to investigate the characteristics of the paleo-climatic
and paleo-environmental changes in Ilan, NE Taiwan by applying environmental
magnetic analyses to a lacustrine core MHL5-A, drilled from Mei-Hwa lake in Ilan,
and expect further to understand the evolution of the East Asia monsoon system.
This study is a part of an integrated project, named as 「Asia Paleo-environmental
Changes」, held by Institute of Earth Sciences, Academia Sinica. The purpose of
this project is to systematically study the paleo-climatic and paleo-environmental
changes since late Pleistocene in East Asia.
Taiwan is located at the intersection of the East Asia. Winter monsoon generated
from Siberia high atmospheric pressure and the summer monsoon originated from
the Indian Ocean. Nonetheless, the heavy rainfalls were generally brought mainly
by the NE winter monsoon and the typhoons during summer and autumn, but not
the summer monsoon. This is due to the high Central Range stems the SW summer
monsoon and horn shape topography faces the NE winter monsoon in Ilan. By
measuring magnetic proxies, such as magnetic susceptibility (χ), natural remanent
magnetization (NRM), anhysteretic remanent magnetization (ARM), and
isothermal remanent magnetization (IRM) etc., we hope to probe into the patterns
of the paleo-climatic and paleo-environmental changes in the study area, Ilan.
The age model of the core was established by 7 C-14 dating data. The results
lead to totally of about 5200 yrs covered by this 28.63 meters core. And the
climatic condition could be concluded into 4 types by the variation trends of the
used magnetic proxies, major by S-ratio, ARM/χ, ARM/SIRM, etc. Twenty
episodes then could be compartmentalized for the last 5200 yrs in Ilan. The
appearance and characteristics of these 4 climate patterns are summarized as follows: (1) During 5300~5000, 4850~4500, 4300~4100, 3700~2950, 2500~2300,
1950~1850, 1700~1400, 1100~700, and 500~400 yr BP: The values of S-ratio
varied small and almost ranged in 0.9~1. This signifies low-oxidized magnetite is
the major magnetic mineral contained in the sediments. The climate then could be
steady and wet. (2) During 5000~4950, 3850~ 3700, 2950~2500, and 1850~1700
yr BP: The values of S-ratio were almost lower than 0.9, even some were lower
than 0.8. Besides the grain size of magnetite is relatively coarser. This indicates
that high-oxidized hematite is the major magnetic mineral in the sediments. The
climate then could be dry. Surface soils may have highly weathered and oxidized
to form much more high-oxidized hematite. As the torrential rain happened,
hematite with coarser grain-sized magnetite could be transported from the
upstream into the lake. (3) During 4950~4850, 4500~4300, 4100~3850, 2300
~1950, 1400~1100, and 700~500 yr BP: The values of S-ratio changed frequently
between 0.8 and 1. The abundance of magnetic minerals also altered frequently.
The climate in these episodes could be very unstable and rainfall happened
frequently. (4) Till the last 400 yrs, the climate also changed frequently, but not so
fast as the climate condition in (3). And it seems had 100~150 years’ period
variation. Moreover, the most different thing from previous episodes is that
relatively much finer grain-sized magnetite were conducted into the lake and it has
happened four times. The delivered mechanism could be due to the floods of
nearby Lo-tung River, which induced much fine grain- sized magnetite overflow
into the lake. Between the occurrences of each flood, the climate might gradually
become dry. So there were less magnetic minerals inputted into the lake. But still
some paramagnetic minerals were eroded into the lake.
In conclusion, the paleo-climatic and paleo-environmental changes severely in
Ilan since the late middle Holocene.

中央地質調查所台灣地區地下水觀測網第二期計畫，「嘉南平原及
蘭陽平原水文地質調查報告，八十八年下半年及八十九年度工
作報告」，經濟部中央地質調查所，共212頁，2001。
中央氣象局全球資訊網: 氣候統計。2007年5月20日，取自
http://www.cwb.gov.tw/。
中央研究院地球科學研究所九十四年度研究成果及論文。2007年5月
20日，取自http://www.sinica.edu.tw/info/research-
results/94/earth1.pdf。
江新春，「宜蘭平原之震測」，礦業技術，第十四卷，第六期，
215-221頁，1976。
李鹿苹，臺灣小區域地理研究集，國立編譯館，臺北市，民國73
年。
林淑芬、劉平妹、黃士強和劉聰桂，「由孢粉紀錄看芝山岩遺址在
六千多年來的古環境變化」，台灣之第四紀第八次研討會暨亞
洲古環境變遷計劃成果發表會論文集，第35頁，2000。
林淑芬，「由孢粉紀錄看宜蘭平原最近4200年來的自然環境演變及
其與史前文化發展之關係」，國立台灣大學，博士論文，民國
93年。
姜善鑫，「宜蘭的氣候變化」，宜蘭研究第一屆學術研討會論文
集，10-35頁，1995。
孫虓天、邱景星、李太楓、陳于高和劉聰桂，「由珊瑚紀錄重建全
新世大暖期之南台灣氣候」，中國地質學會八十八年年會手冊
及論文集，第213-215頁，1999。
陸挽中、劉平妹，「日月潭盆地上次冰期以來之湖泊沉積物孢粉分
析」，台灣之第四紀第六次研討會暨台北盆地地下地質與工程
環境綜合研究成果發表會，254-256頁，1996。
陳文山，「台灣地區地下水觀測網第二期計畫水文地質調查研究八
十九年度報告，沉積物與沉積環境分析及地層對比研究－蘭陽
平原」，經濟部中央地質調查所，共48頁，2000。
陳炳誠、謝孟龍和劉平妹，魚池盆地的地形遷與沉積相，中國地質
學會九十一年年會暨學術研討會摘要集，第47頁，2002。
陳炳誠、謝孟龍和劉平妹，魚池盆地的新期構造，「台灣之第四
紀」第九次研討會論文集，第146頁，2002。
陳鎮東、羅建育、萬政康和藍信企，「中國台灣大鬼湖沈積物所保
留之降塵紀錄」，第四紀研究，21(1)，18-28頁，2001。
陳鎮東、羅建育，「深鎖在大鬼湖中的秘密–沉積物與中國人口的
對應」，科學發展，第369期，30-35頁，2003。
張耀升，「宜蘭地區豪雨個案之研究」，國立中央大學，博士論
文，民國93年。
經濟部中央地質調查所: 地質資料整合查詢-五萬分之一地質圖。
2007年3月10日，取http://datawarehouse.moeacgs.gov.tw
/geo/index/GISSearch/MSDefault.htm。
葉嘉靜，「宜蘭地區秋冬季豪大雨特性之研究」，國立中央大學，
碩士論文，民國92年。
劉平妹、黃淑玉和郭兆敏，「從孢粉紀錄看近數千年台灣的氣候變
遷趨勢」，國立台灣大學地質科學系錢憲和、羅煥記教授榮退
研討會論文集，165-170頁，2002。
劉昭民，中國歷史上氣候之變遷，臺灣商務，臺北市，民國81年。
劉益昌，「宜蘭在台灣考古的重要性」，宜蘭文獻雜誌，第43期，
3-27頁，2000。
劉聰桂、鄒佩珊，「由樹木年輪探討台灣山區近數百年氣候變化」
，全球變遷在台灣研討會摘要及論文，81-84頁，台北，1997。
賴慈華、謝孟龍，「台灣各沖積平原兩萬年來地塊垂直運動速率」
，中國地質學會九十二年年會論文集，第119頁，2003。
謝孟龍、齊士崢、陳邦禮和劉平妹，「蘭陽溪、二仁溪全新世河階
的成因與氣候變遷」，中日地形與環境教育研討會論文集，65-
70頁，1997。
Creer, K.M., R. Thompson, L. Molyneux, and F.J.H.Mackereth.
Geomagnetic secular variation recorded in the stable
remanence of recent sediments. Earth and Planet. Sci.
Lett., 14, 115-127, 1972.
Evans, Michael E. and Heller, Friedrich. Environmental
Magnetism: Principles and Applications of
Environmagnetics. Academic Press., U.S.A., 2003.
Heider, F., A. Zitzelsberger, and K. Fabian. Magnetic
susceptibility and remanent coercive force in grown
magnetite crystals from 0.1 μm to 6 mm. Phys. Earth
and Planet. Int., 93, 239-256, 1996.
Hong, Y.T. A 6000-year record of changes in drought and
precipitation in northeastern China based on a δ13C
time series from peat cellulose. Earth and Planet.Sci.
Lett. , 185, 111-119, 2001.
King, J., S.K. Banerjee, J. Marvin, and O. Ozdemir. A
comparison if different magnetic methods for
determining the relative grain size if magnetite in
nature materials: some results from lake sediments,
Earth and Planet. Sci. Lett., 59, 404-419, 1982.
Lee, T. Q., H. S. Lin and P. M. Liew. Magnetic Analyses on
Lacustrine Deposited Sediments of Yuan-Yang Lake,
Northern Taiwan. J. Geol. Soc. China, 41, 1, 143-158,
1998.
Lee, T.Q., W.C. Lou and P.M. Liew. Paleomagnetic Study of
Lacustrine Sediments from Sun-Moon Lake, Central
Taiwan. Western Pacific Earth Science, 1, 5, 15-26,
2002.
Lee Typhoon, J.H. Chen, C.F. Dai, and J.J. Shen. U-
disequilibrium dating of corals in southern Taiwan by
mass spectrometry. J. Geol. Soc. China. 36, 57-66,
1993.
Lee, Typhoon, Chin-Hsin Chiu, Chuan-Chou Shen, Chang-Feng
Dai, Chung-Ho Wang and Ju-Chin Chen. Coral Sr/Ca as a
High Precision High Time-Resolution Paleo Thermometer
for Sea Surface Temperature: Looking for ENSO Effects
in Kuroshio near Taiwan. Proc. 1995 Nagoya ICBP-
PAGES/PEP-II Symposium, 211-216, 1996.
Letouzey, J. and Kimura, M. The Okinawa trough genesis,
structure and evolution of the backarc basin developed
in a continent. Mar. Petrol. Geol., 2, 111-130, 1986.
Liew, P.M. and Huang S.Y. Pollen analysis and their
paleoclimatic implication in the middle Pleistocene
lake deposits of the Ilan district, Northeastern
Taiwan. Jour. Geol. Soc. China, 37 (1), 115-124, 1993.
Liew, P.M. and Huang, S.Y. A 5000 year’s pollen record
from Chitsai lake, in Central Taiwan. TAO, 5, 3, 411-
420, 1994.
Liew, P.M., Kuo, C.M.Chen, A.C.T. and Lou, J.Y. Climatic
fluctuation during the last several millenia indicated
by lake sediments of Taiwan. Proc. 1995 Nagoya IGBP-
PAGES/PEP-II Symp. Nagoya, 103-108, 1995.
Liew, P.M. Late Quaternary paleomonsoon and its possible
relationship with river deposits..Prog. with extended
Abs. China-Japan Geomorphological Congress, Taipei,
196-197, 1996.
Liew, P.M. A warming induced sea level rise at about 2 ka
yr B.P.: Taiwan as a case. Prog. with Abst. Int. Sym.
Quaternary environmental change in the Asia and
Western Pacific region. Tokyo, 96, 1996.
Liew, P.M., Huang, C.Y. and Tseng, M.H. Preliminary study
on late Quaternary climatic environment of the Taipei
Basin and its possible relation to basin
sediments.Jour. Geol. Soc. China, 40, 1, 17-30, 1997.
Liew, P.M. and Tseng, M.H. Climatic event from the late
glacial to the post glacial in a subtropical monsoon
region, Taiwan. 1998 Third international meeting on
global continental paleohydrology (GLOCOPH).in Japan.
Program with abstract, 73, 1998.
Liew, P.M. and Chung, N. J. Vertical migration of forests
during the last glacial period in subtropical Taiwan.
West. Pacific. Ear. Sci., 1, 4, 405-414, 2001.
Lin, H.S., T.Q. Lee and P.M. Liew. Paleo-secular variation
records from Lacustrine sediments of Yuan-Yang Lake,
northern Taiwan. J. Geol. Soc. China, 38, 4, 355-370,
1995.
Lin, S. F., Liew, P.M. and Lai, T. H. Late Holocene pollen
sequence of the Ilan Plain, northeastern Taiwan and
its environment and climatic implications. Terrestrial,
Atmospheric and Oceanic Sciences (TAO), 15, 2, 111-
132, 2004.
Liu, C.C. The Ilan Pl ain and the southwestward extending
Okinawa Trough. J. Geol. Soc. China, 38, 229-242,
1995.
Mackereth, F. J. H. A portable core sampler for lake
sediment. Limnology and Oceanography, 3, 181-191, 1958.
Mackereth, F.J.H. On the variation in direction of the
horizontal component of remanent magnetization in lake
sediments. Earth and Planet. Sci. Lett., 12, 332-338,
1971.
Magny, M. Solar in£luences on Holocene climatic changes
illus- trated by correlations between past lake-level
fluctuations and the atmospheric 14C record. Quat.
Res., 40, 1-9, 1993.
Meyers, P. Preservation of elemental and isotopic source
identification of sedimentary organic matter. Chem.
Geol., 114, 3-4, 289-302, 1994.
Moskowitz, B.M., Frankel, R.B., Walton, S.A., Dickson,
D.E.P., Wong, K.K.W., Douglas, T., and Mann, S.
Determination of the preexponential frequency factor
for superpara- magnetic maghemite particles in
magnetoferritin. J. Geophys. Res., 102, 22671-22680,
1997.
Peck J.A., J.W. King, S.M. Colman, and V.A. Kravchinsky. A
rock-magnetic record from Lake Baikal, Siberia:
Evidence for Late Quaternary climate change. Earth and
Planet. Sci. Lett., 122, 221-238, 1994.
Redfield, A.C. On the proportions of organic derivatives
in sea water and their relation to the composition of
plankton. ( Daniel, R.J., editor ), In James Johnstone
Memorial Volume., University of Liverpool, 176-192,
1934.
Roberts, A.P., R.L., Reynolds, K.L. Verosub, and D.P.
Adam. Environmental magnetic implications of greigite
(Fe3S4) formation in a 3 m.y. lake sediment record
from Butte Valley, northern California. Geophys. Res.
Lett., 23, 2859-2862, 1996.
Stuiver, M., and Reimer, P.J. Extended 14C data base and
revised calib 3.0 14C age calibration program.
Radiocarbon, 35, 215-230, 1993.
Suppe, J. Kinematics of arc-continent collision, flipping
of subduction, and back-arc spreading near Taiwan.Mem.
Geol. Soc. China, 6, 21-33, 1984.
Thompson, R. Palaeolimnology and palaeomagnetism. Nature,
242, 182-184, 1973.
Thompson, R., R.W. Batterbee, P. E. O’Sullivan, and F.
Oldfield. Magnetic Susceptibility of lake sediments.
Limnology and Oceanography, 20, 687-698, 1975.
Thouveny, N., K.M. Creer, and I. Blunk. Extension of the
Lac du Bouchet palaeomagnetic record over the last
120,000 years. Earth and Planet. Sci. Lett., 97, 140-
161, 1990.
Williams, D.F., J. Peck, E.B. Karabanov, A.A. Prokopenko,
V. Kravchinsky, J. King, and M. I. Kuzmin. Lake Baikal
record of continental climate response to orbital
insolation during the past 5 million years. Science,
278, 1114-1117, 1997.
Yeh, Y.H., Lin, C.H., and Roecker, S.W. A study of upper
crustal structures beneath northeastern Taiwan:
possible evidence of the western extension of Okinawa
Trough. Proc. Geol. Soc. China, 32, 139-156, 1989.
Zhang, D.E. The climatic change in Weihe valley. in: T.S.
Liu (Ed.), Loess, Quaternary Geology and Global
Change, Part 1, Science Press, Beijing, 1-6, 1990.