【摘要】：穩(wěn)定同位素高度計極大地促進了全球較大山體隆升歷史的研究,然而,古土壤氫氧同位素古高度計獲得的古高度結(jié)果一般比通過古生物化石獲得的要高得多.因此,需要在不同地區(qū)深入評估其現(xiàn)代高度關(guān)系及其影響因素,借此探討穩(wěn)定同位素古高度重建方法的校正.本研究測定了青藏高原東部東亞季風(fēng)區(qū)龍門山29個表土葉蠟正構(gòu)烷烴氫同位素值(δD_(wax))、22個土壤水氫同位素值(δD_(sw)),以及貢嘎山47個河水氫同位素值(δD_(rw))、55個泉水的氫同位素值(δD_(springw))和2個水文觀測站的夏季降水氫同位素值(δD_(p)).龍門山斷面表土δD_(wax)值分布在.160~.219‰(其δD_(wax)高程遞減率為.18‰km.1(R2=0.83;p0.0001;n=29),比貢嘎山斷面整體上偏正約40‰.氣候和水汽來源的區(qū)域差異性可能導(dǎo)致了兩個地區(qū)δD_(rw)值、表土δD_(wax)和ε_(wax)/p值的不同.另外,本研究發(fā)現(xiàn)兩個斷面表土δD_(wax)相對δD_(rw)、δD_(p)和δD_(sw)的分餾值(ε_(wax)/_(rw)、ε_(wax)/p和ε_(wax)/_(sw))整體上隨海拔高度的升高而增加(兩個斷面分別高達34‰和50‰).通過這兩個高程斷面的表土δD_(wax)、δD_(p)、δD_(rw)(δD_(springw))和δD_(sw)的對比研究,討論了水汽再循環(huán)、冰川融水、蒸散發(fā)、植被類型、緯度和山形等因素對ε_(wax)/p值隨高程變化的綜合影響.因此,在估算高海拔處的古高度時,如果仍然參考有些低海拔處估算的植物的ε_(wax)/p值,那么,以此推導(dǎo)的古降水δD_(p)偏負于實際值,因而高估古高度.
[Abstract]:The stable isotope altimeter has greatly promoted the study of the uplift history of the world's larger mountain bodies. However, the paleoheight obtained by the paleosol hydrogen and oxygen isotopic altimeters is generally much higher than that obtained by paleontological fossils. Therefore, it is necessary to evaluate the modern height relationship and its influencing factors in different regions, so as to discuss the correction of the reconstruction method of stable isotopic paleoheight. The hydrogen isotope values of normal alkanes (未 D _ (wax),) in 29 topsoil of Longmen Mountain in East Asian monsoon region of the eastern Qinghai-Xizang Plateau (未 D _ (wax), 22) have been determined. The hydrogen isotope values (未 D _ (springw) of 47 river water (未 D _ (rw),) and summer precipitation hydrogen isotopic values (未 D _ (p).) of 45 springs in Gongga Mountain are also given. The 未 D _ (wax) value of the surface soil of Longmen Mountain section is distributed in the range of .160 ~ 0.219 鈥，

本文編號：2392130