本文選題：Smithian-Spathian　切入點(diǎn)：Carnian　出處：《中國(guó)地質(zhì)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：二疊紀(jì)—三疊紀(jì)之交的生物大絕滅是顯生宙最大的一次生物滅絕事件和極端環(huán)境氣候?yàn)?zāi)難,是地球科學(xué)的焦點(diǎn)問(wèn)題之一。長(zhǎng)久以來(lái),學(xué)術(shù)界對(duì)此次大滅絕事件的研究一直保持著極高的熱情,但與此同時(shí)三疊紀(jì)長(zhǎng)達(dá)~50個(gè)百萬(wàn)年的生物復(fù)蘇和輻射階段也伴隨著一系列顯著的環(huán)境氣候事件,其中生物與環(huán)境的協(xié)同演化關(guān)系卻不得人知。二疊紀(jì)末生物大滅絕之后,極端惡劣的環(huán)境氣候條件在早三疊世反復(fù)出現(xiàn),以致海洋生態(tài)系統(tǒng)經(jīng)歷了異常緩慢和曲折的復(fù)蘇重建過(guò)程。其中,早三疊世Smithian-Spathian界線事件見(jiàn)證了一系列顯著的生物、環(huán)境和氣候變化。中三疊世海洋生物類群大規(guī)模輻射演化,形成復(fù)雜且穩(wěn)定的具有現(xiàn)代雛形的生態(tài)系統(tǒng)。晚三疊世海洋生態(tài)系統(tǒng)進(jìn)一步向好,但晚三疊世中Carnian時(shí)期持續(xù)近1個(gè)百萬(wàn)年的超長(zhǎng)強(qiáng)降雨事件不僅嚴(yán)重打擊了早-中三疊世繁盛一時(shí)的生物類群,而且也極大地改變了海洋和陸地生態(tài)系統(tǒng),以及地球生物的演化軌跡。早三疊世Smithian-Spathian界線事件和晚三疊世中Carnian期超長(zhǎng)強(qiáng)降雨事件以氣溫的顯著升降和生物的大規(guī)模滅絕為特點(diǎn),是近些年才被慢慢重視的全球性事件,但對(duì)于這兩次事件過(guò)程中全球氣溫的變化模式、海洋環(huán)境的演變過(guò)程,以及二者間相互關(guān)系的認(rèn)識(shí)還嚴(yán)重不足,對(duì)全球不同地區(qū)事件表現(xiàn)形式的差異性還沒(méi)有全面了解。本文選取古特提斯和泛大洋地區(qū)代表性剖面,利用全巖和牙形石元素和同位素等地球化學(xué)指標(biāo),對(duì)早三疊世Smithian-Spathian界線事件和晚三疊世中Carnian期超長(zhǎng)強(qiáng)降雨事件過(guò)程中海水表層溫度、陸地風(fēng)化作用、海洋鍶同位素組成、海水氧化還原狀態(tài)和海洋碳-硫循環(huán)的演變做了系統(tǒng)研究。在此基礎(chǔ)上,探討了極端環(huán)境氣候事件在古特提斯和泛大洋地區(qū)表現(xiàn)形式上的異同及原因。首先在泛大洋地區(qū)Kamura剖面建立了精確的牙形石生物地層和碳同位素地層格架,并對(duì)剖面沉積歷史做了詳細(xì)研究。在Kamura剖面建立了三疊紀(jì)共14個(gè)牙形石帶。自下而上依次為Hindeodus parvus帶、Isarcicella isarcica帶、Neospathodus dieneri帶、Novipathodus waageni-Parachirognathus帶、Chiosella ex gr.timorensis-Cratognathus帶、Paragondolella excelsa-Pg.alpina帶、Budurovignathus hungaricus帶、B.mungoensis帶、Quadralella tadpole-Gladigondolella malayensis帶、Q.angulata-Q.lobata-Q.carpathica帶、Primatella cf.orchardi-P.permica帶、Epigondolella rigoi-Pa.hallstattensis帶和E.ex gr.bidentata-Norigondolella steinbergensis帶。Kamura剖面二疊紀(jì)-三疊紀(jì)界線位于Mitai組頂部以上0.20米,以H.parvus的首次出現(xiàn)為標(biāo)志;早三疊世-中三疊世界線位于Mitai組頂部以上17.60米,以Ch.ex gr.timorensis的首次出現(xiàn)為標(biāo)志。沉積微相研究表明,晚二疊世生物大滅絕事件發(fā)生時(shí)海平面顯著升高;中-晚Smithian時(shí)期海平面快速下降,并導(dǎo)致整個(gè)Spathian的缺失;中-晚三疊世海平面波動(dòng)不大。Spathian的沉積缺失可能是與Smithian-Spathian界線附近全球降溫導(dǎo)致的海平面下降有關(guān)。牙形石化石材料常被用于古海洋環(huán)境事件分析,因此本文首先探討了牙形石在古海洋環(huán)境事件分析中的技術(shù)方法,包括了牙形石生物磷灰石在成巖作用過(guò)程中元素和同位素的變化,獲得了以下新的認(rèn)識(shí):(1)牙形石REE可以反映原始海水信息,但當(dāng)其圍巖受到陸源碎屑物質(zhì)的嚴(yán)重“污染”時(shí),其中產(chǎn)出的牙形石大多數(shù)無(wú)法記錄原始海水信息。受陸源碎屑物質(zhì)嚴(yán)重“污染”的牙形石碎屑元素(Th、Si、Al和Ni等)和Mn含量很高,U含量很低,MREE強(qiáng)烈富集,Y/Ho和LaN/Yb N比值較低,同時(shí)∑REE和Th有顯著的正相關(guān)性。牙形石在成巖作用過(guò)程中對(duì)元素的吸收開(kāi)始于貧氧帶,主要在成巖作用晚期更深更缺氧的埋藏環(huán)境。牙形石對(duì)元素的選擇性吸收與圍巖性質(zhì)有直接關(guān)系,與樣品時(shí)代無(wú)關(guān)。受陸源碎屑嚴(yán)重“污染”的不同時(shí)代的牙形石,其微量元素組成具有極高的相似性。(2)牙形石生物磷灰石結(jié)構(gòu)和成分具有不均一性。內(nèi)部比表層結(jié)晶度低,牙基比牙尖結(jié)晶度低,牙尖可能是受成巖作用改造最強(qiáng)烈的部位。牙形石表層主要為羥基(氟)磷灰石,內(nèi)部主要是鍶羥基(氟)磷灰石,牙形石內(nèi)部受到的成巖改造最強(qiáng)烈。隨著成巖改造的增強(qiáng),牙形石更富集Sr2+和Mg2+,貧Fe3+、Mn2+和Ca2+。拉曼光譜ν1-PO3-4的峰位(或峰位偏移量SS1)和半高寬(或半高寬偏移量SS2)是識(shí)別元素含量變化的良好指標(biāo)。單一牙形石個(gè)體氧同位素存在較大差異,乳白色牙冠比玻璃質(zhì)牙冠和牙基低0.28-0.32‰。牙形石內(nèi)部比表層低1.08±0.37‰。此外,牙形石乳白色牙冠比其它部位重結(jié)晶程度要高,牙形石內(nèi)部比外部具有更多的外來(lái)離子(如,Sr2+),因此牙形石乳白色牙冠和牙形石內(nèi)部可能是受成巖作用改造最嚴(yán)重的部位。Smithian-Spathian界線綜述研究表明,菊石關(guān)鍵屬(如,晚Smithian菊石Anawasatchites、Anasibirites、Glyptophiceras和Xenoceltites;早Spathian菊石Bajarunia、Tirolites和Columbites)和牙形石關(guān)鍵種(如,Novispathodus pingdingshanensis、Budurovignathus hungaricus和Neogondolella aff.sweeti)是定義Smithian-Spathian界線重要的生物標(biāo)志。碳同位素的正偏移(從N3到P3,或從m(N3-P3)到P3)是定義Smithian-Spathian界線的重要輔助標(biāo)志。對(duì)前人Smithian-Spathian界線位置的修正結(jié)果顯示,Smithian極熱事件位于碳同位素曲線N3和m(N3-P3)之間,Smithian-Spathian界線對(duì)應(yīng)全球氣溫的顯著下降。安徽巢湖平頂山西剖面是早三疊世Smithian-Spathian界線研究的重要參考剖面。本文在古特提斯東部中國(guó)華南地區(qū)三個(gè)Smithian-Spathian界線剖面(石頭寨、平頂山西和甲戎)和泛大洋西部日本Kamura剖面系統(tǒng)研究了Smithian-Spathian界線事件,獲得了以下新認(rèn)識(shí):(1)在Smithian時(shí)期,泛大洋地區(qū)海水表層溫度比古特提斯地區(qū)低約8-12℃,以往認(rèn)為的Smithian極熱事件在泛大洋地區(qū)并不明顯。(2)早-中Smithian隨著氣溫升高,古特提斯地區(qū)有大量的碎屑物質(zhì)輸入,同時(shí)泛大洋地區(qū)碎屑物含量也有比較明顯的增加;晚Smithian早期古特提斯地區(qū)氣溫顯著下降,但是陸地風(fēng)化速率依舊很高,而泛大洋地區(qū)比較敏感,碎屑物含量在Smithian晚期就有明顯的下降。(3)在Smithian晚期,古特提斯淺水地區(qū)海水缺氧狀況有明顯改善,而古特提斯深水地區(qū)和泛大洋淺水地區(qū)缺氧程度增加,直到Spathian早期古特提斯深水地區(qū)海水缺氧狀況才有明顯改善。(4)在Smithian時(shí)期,古特提斯和泛大洋淺水地區(qū)δ~(13)Ccarb與δ~(34)SCAS呈負(fù)相關(guān)演變模式,而古特提斯深水地區(qū)呈正相關(guān)演變模式,且泛大洋地區(qū)δ~(34)SCAS值明顯低于古特提斯地區(qū)。Griesbachian和Dienerian時(shí)期泛大洋地區(qū)δ~(34)SCAS也明顯低于古特提斯地區(qū),δ~(13)Ccarb-δ~(34)SCAS負(fù)相關(guān)演變模式也與特提斯地區(qū)有顯著差別。古特提斯深水相和淺水相碳-硫循環(huán)模式的差異與降溫導(dǎo)致的海洋循環(huán)加快和海洋生產(chǎn)力的提高有關(guān)。而泛大洋碳-硫循環(huán)模式可能與這一地區(qū)極低的硫酸鹽濃度和較低的硫的海水滯留時(shí)間有關(guān)。本文在古特提斯東部華南姚家灣剖面和泛大洋西部日本Kamura剖面系統(tǒng)研究了中Carnian超長(zhǎng)強(qiáng)降雨事件,獲得了以下新認(rèn)識(shí):(1)中Carnian超長(zhǎng)強(qiáng)降雨事件期間,古特提斯和泛大洋地區(qū)海水表層溫度均有明顯升高,升幅約5-7℃。(2)與氣溫升高同步,陸地風(fēng)化作用顯著增強(qiáng),海水還原程度增加,海洋碳-硫循環(huán)異常。特提斯地區(qū)碎屑輸入量明顯高于泛大洋地區(qū)。(3)泛大洋地區(qū)由于遠(yuǎn)離大陸保存與全球海水一致的87Sr/86Sr值,87Sr/86Sr在Carnian期呈緩慢上升的趨勢(shì)。(4)中Carnian事件期間,古特提斯和泛大洋地區(qū)海水都發(fā)生了嚴(yán)重的缺氧甚至硫化。其中古特提斯海水缺氧程度明顯高于泛大洋地區(qū),且持續(xù)時(shí)間更長(zhǎng)。(5)中Carnian超長(zhǎng)強(qiáng)降雨事件期間,古特提斯和泛大洋地區(qū)海水δ~(13)C和/或δ~(34)S均發(fā)生了同步的負(fù)偏移,與這一時(shí)期氣溫的升高同步。事件期間,全球碳同位素的負(fù)偏移可能與同時(shí)期的火山作用有關(guān),這一時(shí)期海洋碳硫循環(huán)異常反映了氣候變化和火山作用對(duì)海洋環(huán)境的共同影響。
[Abstract]:Biological extinction of Permian Triassic extinction event is one of the largest Phanerozoic and extreme environmental climate disaster is one of the hot issues of earth science. For a long time, research on the mass extinction event in academic circles has maintained a high enthusiasm, but at the same time for recovery of ~50 million in the year and the radiation phase also accompanied by a series of significant climate events, including the co evolution relationship between organisms and environment is not known. After the end Permian mass extinction, climate extremes appear repeatedly in the Early Triassic three, so that the marine ecosystem has experienced a slow and tortuous process of recovery and reconstruction. The abnormal three, early Triassic Smithian-Spathian boundary event witnessed a series of significant biological, environmental and climate change. In three groups of large-scale Triassic marine biological evolutionary radiation The formation of complex and stable, with a modern prototype ecosystem. Further the better late three Triassic marine ecosystems, but late Triassic in the three Carnian period lasted nearly 1 millions of years long heavy rainfall event is not only a serious blow to the organism in three early Triassic flourished, but also greatly changed marine and terrestrial ecosystems, and the earth's biological evolution trajectory. As early as three Smithian-Spathian and Late Triassic boundary event in Triassic period three Carnian long heavy rainfall events characterized by significant mass extinction and biological temperature lifting, is a global event in recent years is gradually attention, but for the two models of global change the incident process temperature, the evolution process of the marine environment, and study the relationship between the two is seriously insufficient, the difference of different parts of the world event form is not fully understand This paper selects Gut Tis and Pan Ocean area representative section, using the whole rock and conodont elements and isotopic geochemical indicators of sea surface temperature in early three and Late Triassic boundary event Smithian-Spathian three Carnian in the Triassic period long heavy rainfall events in the process of terrestrial weathering, marine strontium isotopic composition of seawater. Redox status and evolution of marine carbon - sulfur cycle were studied. On this basis, discussed the differences and reasons of extreme climate events in the environment of Gut Tis and Pan Ocean area form. The first section is established in the Fan Dayang area Kamura precise conodont biostratigraphy and carbon isotope stratigraphy, and the sedimentary history is studied in detail in section Kamura. A total of 14 Triassic conodont zones. Followed by bottom-up Hindeodus parvus, Isarcicella isarcica, Neospa Thodus dieneri, Novipathodus waageni-Parachirognathus Chiosella ex gr.timorensis-Cratognathus, Paragondolella excelsa-Pg.alpina, Budurovignathus hungaricus, B.mungoensis, Quadralella, tadpole-Gladigondolella malayensis, Q.angulata-Q.lobata-Q.carpathica Primatella cf.orchardi-P.permica, Epigondolella rigoi-Pa.hallstattensis and E.ex, with gr.bidentata-Norigondolella steinbergensis with the.Kamura profile of Permian Triassic boundary is located at 0.20 meters above the top of group Mitai, which appeared for the first time for H.parvus mark; Early Triassic in three three fold line located above the world top 17.60 meters in the Mitai group, Ch.ex gr.timorensis first appeared as a symbol. The sedimentary microfacies research shows that sea level increased significantly in the Late Permian mass extinction event occurs in the late period of Smithian; when the sea level fast Drop, and cause the lack of the entire Spathian; absence of sediment middle - Late Triassic three sea-level fluctuations do not.Spathian may be related to global cooling caused the sea level near the boundary of Smithian-Spathian decreased. Conodont material is often used in the analysis of the ancient marine environment, therefore this paper discusses the technical method in the analysis of ancient marine environment in the event of conodonts, including conodont apatite in biological changes of elements and isotopes during the diagenetic process, obtained the following new ideas: (1) the conodont REE can reflect the information of sea water, but when the surrounding rock has been a serious "pollution" of detrital material, which shaped teeth most of the original ore output to record information. By the sea of terrigenous material "serious pollution" of the conodont clastic elements (Th, Si, Al and Ni) and the content of Mn is high, U content is very low, strong enrichment of MREE, Y/Ho LaN/Yb and N ratio is low, at the same time REE and Th have significant positive correlation. The conodont elements began to absorb during diagenesis in oxygen depleted zone, mainly in the late diagenesis of deeper burial environment. Hypoxia selective conodont elements on the absorption have a direct relationship with the surrounding rock nature has nothing to do with the sample time. By terrigenous serious "pollution" of the different age of conodont, similar composition with high trace elements. (2) the conodont biological apatite structure and composition inhomogeneity. The internal degree is lower than the surface crystallization, tooth cusp than low crystallinity, teeth the tip may be affected by a part of the diagenetic transformation. The strongest conodont surface layer is mainly hydroxyl apatite (fluorine), is the main internal strontium (fluoro) hydroxy apatite, conodont diagenesis is most intense. With the enhancement of diagenesis, the conodont is more enriched in Sr2+ and Mg2+ Poor Fe3+, Mn2+, Ca2+. and Raman spectra of V 1-PO3-4 (peak or peak offset SS1) and half width (or half width SS2 offset) is a good indicator to recognize the change of element content. Single conodont individual oxygen isotope differences, milky white crown than vitreous crown and abutment low 0.28-0.32 per thousand. Conodont internal 1.08 + lower than the surface of 0.37 per thousand. In addition, the conodont milky white crown degree is higher than that of other parts of recrystallization, conodont has more than external foreign ions (e.g., Sr2+), so the conodont white crown and conodonts in May is of the most serious parts of the.Smithian-Spathian line summary of the diagenetic transformation shows that the key is ammonite (e.g., late Smithian Anawasatchites Anasibirites, Glyptophiceras and ammonites, Xenoceltites; Spathian Bajarunia Tirolites and early ammonoids, Columbites) and conodonts of key species (e.g., Nov Ispathodus pingdingshanensis, Budurovignathus hungaricus and Neogondolella aff.sweeti) is defined as the Smithian-Spathian line of important biological markers. A positive offset carbon isotope (from N3 to P3, or from m to P3 (N3-P3)) is an important auxiliary sign defined the Smithian-Spathian boundary. The correction results of previous Smithian-Spathian line position display, Smithian is located in the extreme heat events of carbon isotope curve N3 and m (N3-P3), Smithian-Spathian line decreased significantly the corresponding global temperature. Anhui Chaohu flat section of Shanxi is an important reference section of the Smithian-Spathian line three early Triassic. This paper in the three Smithian-Spathian boundary section of the Paleo Tethys Eastern Southern China area (Chinese Shitouzhai, flat topped Shanxi and a Rong) and Pan Ocean in western Japan Kamura study on the Smithian-Spathian boundary event profile system, obtained the following understanding: (1) in In the period of Smithian, the pan Bigutetisi sea surface temperature of the ocean area low of about 8-12 DEG Smithian, the past that extreme heat events is not obvious in the ocean area. (2) early in the Smithian as temperatures rise, the Paleo Tethys region has plenty of detrital material input, while content of debris pan ocean area also increased; the temperature of late Smithian early Paleo Tethys region decreased significantly, but the land weathering rate remains high, while the Pan Ocean area is relatively sensitive, significantly reduced debris content is in the late Smithian. (3) in the late Smithian, seawater hypoxia in shallow water area has obviously improved the Paleo Tethys, and the degree of hypoxia of Gut Tis and Pan Ocean deepwater area shallow water area increased, until the early Spathian Paleo-Tethyan deepwater area sea water anoxic condition have improved significantly. (4) in the Smithian period, Gut Tis and pan The shallow ocean area 8 ~ (13) Ccarb and 8 ~ (34) SCAS was negatively related to the evolution mode, and positively related Gut Tis deep-water area evolution pattern, and Pan Ocean area 8 ~ (34) SCAS value was significantly lower than that of the Paleo Tethys ocean area and Dienerian area of Pan.Griesbachian period 8 ~ (34) SCAS was significantly lower than the Paleo Tethys region, delta ~ (13) Ccarb- 8 ~ (34) SCAS negative correlation models have significant difference with the evolution of Tethys region. The difference of Paleo Tethys deep-water facies and shallow water phase carbon sulfur cycle model and ocean circulation cooling leads to speed up and improve the marine productivity. While the Pan Ocean Carbon - sulfur cycle model may sulfate the concentration of this region is very low and low sulfur water retention time related in this article. The Paleo Tethys eastern Gulf of Southern China Yao home and Pan Ocean profile in western Japan was studied in the Kamura section of Carnian long heavy rainfall events, obtained the following New understanding: (1) during the heavy rainfall event in the long Carnian, Gut Tis and Pan Ocean region sea surface temperature increased significantly, an increase of about 5-7 degrees Celsius. (2) increased synchronously with the temperature, continental weathering effect increase, water reduction degree increased, the marine carbon - sulfur cycle. Abnormal clastic input Tethys region was significantly higher than that of Pan Ocean area. (3) away from the mainland and the preservation of global seawater consistent 87Sr/86Sr values of Pan Ocean area, 87Sr/86Sr showed a slow upward trend in the period of Carnian. (4) during the Carnian event, Gut Tis and Pan Ocean sea area have undergone severe hypoxia and sulphide. Which Paleo-Tethyan hypoxic water was obviously higher than that of pan the ocean area, and for a longer period of time. (5) during the heavy rainfall event in the long Carnian, Gut Tis and Pan Ocean Sea Delta region ~ (13) C and / or 8 ~ (34) S had negative offset synchronization, and During the same period, the negative shift of global carbon isotope may be related to the same period of volcanism. During this period, the marine carbon and sulfur cycle anomaly reflected the common influence of climate change and volcanism on the marine environment.

【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：P534.51;P532
，

本文編號(hào)：1582215