全新世早期島尾Ⅰ、Ⅱ遺址瘤岩螺殼體穩定同位素紀錄所反映之馬祖亮島地區古環境及採收季節
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2025
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本研究分析馬祖亮島島尾Ⅰ遺址(距今約7900至7300年前)中9隻瘤岩螺殼體、亮島島尾Ⅱ遺址(距今約5800至5100年前)中6隻瘤岩螺殼體和現今馬祖南竿地區6隻不同時間所採集的螺類殼體之穩定碳、氧同位素成分，結合馬祖地區水體之穩定氫、氧同位素紀錄，探討約距今約7900至5100年前之古環境。馬祖北竿白沙水體之穩定氫、氧同位素數值（V-SMOW）分別介於-7.9至2.4‰(平均值-2.5±2.5；N=54)及-1.8至-0.1‰之間(平均值-0.8±0.4‰)，南竿復興水體之穩定氫、氧同位素數值分別介於-7.5至3.0‰ (平均值-2.9±2.6‰；N=55)和-1.5至0.0 ‰之間(平均值-0.8±0.4‰)。統整現代水體穩定氫、氧同位素紀錄及該地區之温度、鹽度、降雨量等資料，該地區受到中國東部及東南部沿岸地區淡水匯入的影響。馬祖南竿地區所分析6隻現生螺類殼體之穩定碳、氧同位素數值（V-PDB）分別介於-2.4‰至-1.0‰之間(平均值-0.3±0.7‰；N=394)和-2.7‰至0.1‰之間(平均值-1.6±0.4‰)，現生螺類殼體的氧同位素數值與理論平衡氧同位素數值大致相似，但螺類在冬季時會因為生長緩慢或停止生長而未記錄到最低温的訊號。馬祖亮島島尾Ⅰ遺址中9隻瘤岩螺殼體之穩定碳、氧同位素數值介於-1.9‰至2.7‰之間(平均值0.8±0.7‰；N=1327)和-3.5‰至0.7‰之間(平均值-1.5±0.5‰)，島尾Ⅱ遺址6隻瘤岩螺殼體之穩定碳、氧同位素數值介於-1.4‰至2.6‰之間(平均值0.8±0.7‰；N=1059)和-3.3‰至0.5‰之間(平均值-1.6±0.6‰)。兩個遺址瘤岩螺殼體之平均碳同位素數值均比現生螺類殼體之平均碳同位素數值較大約1.1‰，可能是因為距今約8000年前全球海平面較現今海平面低約20公尺，造成當時亮島和周圍主要陸地之海岸線距離變短，比現今更易受到中國沿岸地區淡水所攜入之陸源物質的影響，導致當時的亮島附近海域的營養鹽增加，使得當時的海洋基礎生產力比現今為高。根據單一殼體氧同位素紀錄及四分位法協助判斷螺類生長時氧同位素數值之變化趨勢，島尾Ⅰ遺址中瘤岩螺殼體的採收季節分佈於秋季(N=4)、春季(N=2)、春夏季之間(N=2)和夏秋季之間(N=1)。島尾Ⅱ遺址的採收季節分佈於春季(N=4)、春夏季之間(N=1)和秋冬之間(N=1)。尾Ⅰ遺址之平均夏天氧同位素數值為-2.3±0.4‰（N=35），假設距今約7900至7300年前的海水氧同位素數值比現今大0.2‰，將現今夏天水體的氧同位素數值（-0.5±0.3‰；N=3）校正冰川效應後，島尾Ⅰ遺址之夏天的平均海水氧同位素温度為28.3℃。島尾Ⅱ遺址之平均夏天氧同位素數值為-2.4±0.4‰（N=29），因距今約5800至5100年前的海平面與現今大致相同而無須校正冰川效應，故島尾Ⅱ遺址之平均海水夏天氧同位素温度為27.8℃。島尾Ⅰ遺址和島尾Ⅱ遺址瘤岩螺殼體所反映之距今約7900至7300年前和距今約5800至5100年前的亮島地區的夏季和現今夏季（約28℃）一樣温暖的環境。
This study analyzes the stable carbon and oxygen isotope compositions of 9 Reishia luteostoma shells from the archaeological Liang island Dao-Wei site I (from 7,900 to 7,300 years B.P.), 6 shells from the archaeological Liang island Dao-Wei site II (from 5,800 to 5,100 years B.P.), and 6 modern gastropod shells collected at different times from the Nangan area of Matsu. Combined with the stable hydrogen and oxygen isotope records of seawater collected from the Matsu region, this study reconstructs the paleoenvironment of Liang island area between 7,900 and 5,100 years B.P..The stable hydrogen and oxygen isotope values (V-SMOW) of water collected from Beigan area, range from -7.9‰ to 2.4‰ (average value -2.5 ± 2.5‰; N = 54)and from -0.1‰ to -1.8‰ (average value -0.8 ± 0.4‰), respectively. In Nangan area, the hydrogen and oxygen isotope values are respectively between -7.5‰ and 3.0‰ (average value -2.9 ± 2.6‰; N = 55) and between 0.0‰ and -1.5‰ (average value -0.8 ± 0.4‰). Based on analyses of modern seawater isotopic compositions, temperature, salinity, and rainfall records in the region, it is inferred that seawater in this area is influenced by freshwater input from the southeastern and eastern coast of China.The carbon and oxygen isotope values (V-PDB) of the six modern gastropod shells from Nangan range from -2.4‰ to -1.0‰ (average value -0.3 ± 0.7‰; N = 394) and from collected -2.7‰ to 0.1‰ (average value -1.6 ± 0.4‰), respectively. By comparing individual modern gastropod shell oxygen isotope values to the oxygen isotope equilibrium values estimatd from the observed water oxygen isotope values and corresponding temperature, the overall oxygen isotope values recorded by the modern gastropod shells reach apparently isotope equilibrium except the lowest winter temperatures are not recorded. This may be due to these shells tend to slow down the precipitation rate of the shell or even cease of growth during winter.The carbon and oxygen isotope values of the 9 Reishia luteostoma shells collected from the Dao-Wei site I, range from -1.9‰ to 2.7‰ (average value 0.8 ± 0.7‰; N = 1327) and from -3.5‰ to 0.7‰ (average value -1.5 ± 0.5‰), respectively. The isotope values of the 6 shells collected from the Dao-Wei site II, range from -1.4‰ to 2.6‰ (average value 0.8 ± 0.7‰; N = 1059) for carbon isotope, and from -3.3‰ to 0.5‰ (average value -1.6 ± 0.6‰) for oxygen isotope. The mean δ¹³C values of shells collected from both archaeological sites are are approximately 1.1‰ greater than that of the modern specimens. This may be attributed to the sea level being approximately 20 meters lower than present around 8,000 years ago. As a result, the surrounding marine environment was more strongly influenced by terrestrial inputs carried by freshwater from the southeastern and eastern coast of China. This likely increased nutrient availability in the coastal waters near Liang Island, leading to higher primary marine productivity compared to the present.Harvest seasons are inferred using δ¹⁸O trends of individual Reishia luteostoma shells combined with a quartile-based classification. The harvest seasons of R. luteostoma for Dao-Wei Site I were distributed in autumn (N = 4): spring (N = 2), spring to summer (N = 2), and summer to autumn (N = 1). The harvest seasons of R. luteostoma for Dao-Wei Site II were distributed in spring (N = 4), between spring and summer (N = 1), and between autumn and winter (N = 1). The average summer oxygen isotope value of archaeological shells for the Dao-Wei site I is -2.3 ± 0.4‰ (N = 35). Assuming that the seawater δ¹⁸O value was approximately 0.2‰ higher than present (-0.5 ± 0.3‰; N = 3), the estimated summer seawater temperature at Liang island was 28.3°C in 7900-7300 years B.P.. The average summer oxygen isotope value of Dao-Wei Site II archaeological shells was -2.4 ± 0.4‰ (N = 29). Because the sea level from 5800 to 5100 years B.P. was comparable to that of the present, no glacial correction was applied. The resulting estimated summer seawater temperature for Liang island was 27.8°C in 5800 - 5100 years B.P.. These results suggest that the summer temperatures in the Liang Island region during both 7900 to 7300 yr. B.P. and 5800 to 5100 yr. B.P. was as warm as it is today (approximately 28°C).
This study analyzes the stable carbon and oxygen isotope compositions of 9 Reishia luteostoma shells from the archaeological Liang island Dao-Wei site I (from 7,900 to 7,300 years B.P.), 6 shells from the archaeological Liang island Dao-Wei site II (from 5,800 to 5,100 years B.P.), and 6 modern gastropod shells collected at different times from the Nangan area of Matsu. Combined with the stable hydrogen and oxygen isotope records of seawater collected from the Matsu region, this study reconstructs the paleoenvironment of Liang island area between 7,900 and 5,100 years B.P..The stable hydrogen and oxygen isotope values (V-SMOW) of water collected from Beigan area, range from -7.9‰ to 2.4‰ (average value -2.5 ± 2.5‰; N = 54)and from -0.1‰ to -1.8‰ (average value -0.8 ± 0.4‰), respectively. In Nangan area, the hydrogen and oxygen isotope values are respectively between -7.5‰ and 3.0‰ (average value -2.9 ± 2.6‰; N = 55) and between 0.0‰ and -1.5‰ (average value -0.8 ± 0.4‰). Based on analyses of modern seawater isotopic compositions, temperature, salinity, and rainfall records in the region, it is inferred that seawater in this area is influenced by freshwater input from the southeastern and eastern coast of China.The carbon and oxygen isotope values (V-PDB) of the six modern gastropod shells from Nangan range from -2.4‰ to -1.0‰ (average value -0.3 ± 0.7‰; N = 394) and from collected -2.7‰ to 0.1‰ (average value -1.6 ± 0.4‰), respectively. By comparing individual modern gastropod shell oxygen isotope values to the oxygen isotope equilibrium values estimatd from the observed water oxygen isotope values and corresponding temperature, the overall oxygen isotope values recorded by the modern gastropod shells reach apparently isotope equilibrium except the lowest winter temperatures are not recorded. This may be due to these shells tend to slow down the precipitation rate of the shell or even cease of growth during winter.The carbon and oxygen isotope values of the 9 Reishia luteostoma shells collected from the Dao-Wei site I, range from -1.9‰ to 2.7‰ (average value 0.8 ± 0.7‰; N = 1327) and from -3.5‰ to 0.7‰ (average value -1.5 ± 0.5‰), respectively. The isotope values of the 6 shells collected from the Dao-Wei site II, range from -1.4‰ to 2.6‰ (average value 0.8 ± 0.7‰; N = 1059) for carbon isotope, and from -3.3‰ to 0.5‰ (average value -1.6 ± 0.6‰) for oxygen isotope. The mean δ¹³C values of shells collected from both archaeological sites are are approximately 1.1‰ greater than that of the modern specimens. This may be attributed to the sea level being approximately 20 meters lower than present around 8,000 years ago. As a result, the surrounding marine environment was more strongly influenced by terrestrial inputs carried by freshwater from the southeastern and eastern coast of China. This likely increased nutrient availability in the coastal waters near Liang Island, leading to higher primary marine productivity compared to the present.Harvest seasons are inferred using δ¹⁸O trends of individual Reishia luteostoma shells combined with a quartile-based classification. The harvest seasons of R. luteostoma for Dao-Wei Site I were distributed in autumn (N = 4): spring (N = 2), spring to summer (N = 2), and summer to autumn (N = 1). The harvest seasons of R. luteostoma for Dao-Wei Site II were distributed in spring (N = 4), between spring and summer (N = 1), and between autumn and winter (N = 1). The average summer oxygen isotope value of archaeological shells for the Dao-Wei site I is -2.3 ± 0.4‰ (N = 35). Assuming that the seawater δ¹⁸O value was approximately 0.2‰ higher than present (-0.5 ± 0.3‰; N = 3), the estimated summer seawater temperature at Liang island was 28.3°C in 7900-7300 years B.P.. The average summer oxygen isotope value of Dao-Wei Site II archaeological shells was -2.4 ± 0.4‰ (N = 29). Because the sea level from 5800 to 5100 years B.P. was comparable to that of the present, no glacial correction was applied. The resulting estimated summer seawater temperature for Liang island was 27.8°C in 5800 - 5100 years B.P.. These results suggest that the summer temperatures in the Liang Island region during both 7900 to 7300 yr. B.P. and 5800 to 5100 yr. B.P. was as warm as it is today (approximately 28°C).
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古環境, 島尾遺址, 亮島, 馬祖, 穩定同位素, 瘤岩螺, paleoenvironment, archaeological Dao-Wei site, Liang Island, Mastu area, stable isotope, Reishia luteostoma