Thesis (M.S. in Management)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Hildebrandt, Gregory ; Franck, Raymond. "March 2010." Author(s) subject terms: South Korea, North Korea, Korean Unification, Korean Reunification, Republic of Korea Army, People's Republic of China, People's Liberation Army, German unification, TASC score, Military Integration, Korean People's Army. Includes bibliographical references (p. 67-69). Also available in print.

Thesis (Ph. D.)--Columbia University, 1992. / Includes bibliographical references (leaves 259-273).

The primary objective of this thesis was to date the age of gold mineralization in the Jiaodong and Liaodong Peninsulas, China. Based on SHRIMP U-Pb zircon ages of dykes and host rocks at 13 gold deposits in the two peninsulas and the 40(subscript)Ar-39(subscript)Ar dating of sericite at the Cangshang deposit in the Jiaodong Peninsula, a single gold mineralization event at ca. 122 - 119 Ma has been identified.Ten gold deposits in the Jiaodong Peninsula and three gold deposits in the Liaodong Peninsula were examined. Gold mineralization can be divided into the disseminated-and-veinlet type (Jiaojla-style) and vein type (Linglong-style) and all these deposits are strongly controlled by faults. The most common host rocks are granitoids, with a SHRIMP 206(subscript)Pb/238(subscript)U age of 150 - 165 Ma. The youngest host rocks in the Jiaodong Peninsula are granodiorite, with an age of ca. 128 Ma. The oldest dated host rock in the Jiaodong Peninsula is amphibolite with a metamorphic zircon age of 1852 plus or minus 37 Ma; in the Liaodong Peninsula, the oldest host rock is metasandstone with the youngest detrital zircon giving an age of 1886 plus or minus16 Ma. The Jiaodong and Liaodong Peninsulas are underlain by Precambrian basement with components up to ca. 3.7 Ga old and these are reflected in the zircon population. There are three main peaks of inherited zircons, which yield Late Archaean (ca. 2500 Ma), Palaeoproterozoic (1800-2200 Ma) and Early Mesozoic (ca. 200-250 Ma) ages.The close spatial and temporal relationships between dykes and gold mineralization has only recently been recognized in China. Based on the cross-cutting relationship between dykes and gold lodes (and the alteration style of dykes), three types of dykes are recognized: pre-, syn- and post-mineralization dykes. Premineralization dykes yield an age of ca. 124 Ma; syn-mineralization dykes give an ++ / age of ca. 122-119 Ma, which can also be interpreted as the time of gold mineralization; further work is needed to date post-mineralization dykes, since no suitable samples were identified during this study.40(subscript)Ar-39(subscript)Ar dating of sericite has been used to determine the timing of gold mineralization at the Cangshang Gold Deposit. It gives a well-defined 40(subscript)Ar-39(subscript)Ar age of 121.3 plus or minus 0.2 Ma.The second objective of this thesis was to understand why the tectonic setting of the Jiaodong and Liaodong Peninsulas is favourable for gold formation and what is a sound genetic model for these gold deposits. Based on this study, it is interpreted that multiple orogenic events created a favourable tectonic environment for the Jiaodong and Liaodong gold deposits. It is suggested that delamination related to orogenic events occurred beneath the Jiaodong and Liaodong Peninsulas. The substantial heat and fluid transfer caused by delamination allowed mantle-derived magma and auriferous fluids to be channelled along deep faults to favourable structures within the crust. This probably explains why the dykes and gold lodes are closely associated in both time and space.

Thesis (M.A. in Security Studies (Far East, Southeast Asia, and The Pacific))--Naval Postgraduate School, June 2009. / Thesis Advisor(s): Twomey, Christopher. "June 2009." Description based on title screen as viewed on July 10, 2009. Author(s) subject terms: North Korean refugees, Six Party, Republic of Korea, ROK, South Korea, Democratic People's Republic of Korea, DPRK, North Korea, China, Japan, Russia, Northeast Asia regional stability, UNC, CFC, USFK, UNC Rear, UNC Sending States, Korean diaspora, assimilation, immigration, human rights, humanitarian assistance, stability and reconstruction operations. Includes bibliographical references (p. 65-70). Also available in print.

Thesis (Ph. D.)--Indiana University, 2001. / Vita. Includes bibliographical references (leaves 237-265).

Thesis (Ph. D.)--University of Connecticut, 1990. / Abstract (2 leaves) bound with copy. Includes bibliographical references (leaves 254-267).

The Miocene climate evolution in North China is preliminarily discussed by means of comparisons in seven climate parameters quantitatively reconstructed by the Coexistence Approach on 34 selected macro- and microfloras over North China. The Miocene temperatures show no great difference in the western and eastern part of North China. Temperature fluctuations, particularly in mean annual temperature, are found within floras from several sites. The fluctuation pattern, from a climate optimum in the Mid Miocene to cooling decline in the Late Miocene, is generally consistent with the global trend of Miocene temperature change. The reconstructed precipitation from all the sites studied shows much wetter conditions in North China during the Miocene than at present, which corroborates the results from paleoprecipitation proxy of fossil mammals. Like the situation in paleo-temperature, the Miocene precipitation from North China shows no distinct difference between the western and eastern regions. It is suggested that North China, particularly in the western part, was by no means under an arid or semi-arid environment during the Miocene. North China is an ideal region for study of the impact of the East Asian monsoon system, however, the pattern of precipitation change derived from the monsoon index (MSH) and mean annual precipitation (MAP) shows contradictory results. Therefore, there appears no definite conclusion on when the East Asian summer monsoon intensified. Possible reasons for inconsistency in temperature and precipitation changes are discussed. Directions of future work to improve the resolution of climate evolution are also pointed out.

Ce travail de thèse est essentiellement consacré à l'étude du style tectonique et de l'évolution géodynamique de la "Trans-North China Belt", chaîne de collision marquant la fermeture du Craton de Chine du Nord au Paléoprotérozoïque. Cinq principaux massifs ont fait l'objet d'une étude de terrain détaillée, mettant l'accent sur la géométrie des structures et leur cinématique et permettant de distinguer plusieurs unités lithotectoniques aux caractères métamorphiques distincts. Les contraintes temporelles du magmatisme, du métamorphisme et de la déformation ont été obtenues par la datation U-Th-Pb sur monazite à la microsonde électronique, la datation 40Ar/39Ar sur monograins d'amphibole, de biotite et de muscovite et la datation U-Pb LA-ICP-MS sur zircon. Deux domaines sont distingués. Le premier est caractérisé par une tectonique tangentielle. L'unité "LGMU" (Low-Grade Mafic Unit) est interprétée comme une nappe ophiolitique qui s'enracine le long de la "Trans-North China Suture", située dans la partie ouest de la chaîne. Cette nappe chevauche vers le SE l'unité "OVU" (Orthogneiss-and-Volcanites Unit), composée d'une série volcano-sédimentaire et d'orthogneiss métamorphisés dans le faciès des amphibolites. Ces roches, dont les protolithes sont datés vers 2.5 Ga et 2.1 Ga, sont impliquées dans l'orogenèse de collision caractérisée par une histoire polyphasée entre 1900 Ma et 1800 Ma. En complément des résultats des datations U-Th-Pb et U-Pb, une étude thermobarométrique réalisée sur un micaschiste à disthène et staurotide conduit à la construction d'un chemin Pression-Température-Déformation-temps prograde qui vient confirmer l'âge de la mise en place des nappes et de l'épaississement crustal vers 1880 Ma. Le second domaine, constitue le para-autochtone sur lequel l'unité "OVU" est charriée. Ce domaine est caractérisé par une structure en "dôme-et-bassin", interprétée comme le résultat d'un diapirisme dans un champ de déformation défini par un étirement E-W et un raccourcissement N-S. Cette tectonique "archaïque" est datée vers 2.1 Ga. Enfin, l'étude préliminaire du massif de Zanhuang, situé à l'est du para-autochtone permet de mettre en évidence une seconde zone de suture où s'empilent, selon une vergence Est, des écailles de roches ophiolitiques et de marge passive continentale. La synthèse de l'ensemble des résultats conduit à la reconstruction de la structure globale du segment de chaîne considéré, depuis les zones internes jusqu'aux zones externes. En outre, nous proposons un modèle géodynamique qui implique trois blocs néoarchéens, le Bloc de l'Ouest, le Bloc de Fuping et le Bloc de l'Est, séparés par deux océans, l'Océan de Lüliang et l'Océan de Taihang. L'ouverture des domaines océaniques s'opère vers 2175 Ma. La collision à ~1880 Ma, en réponse à leur fermeture, est responsable de la structuration principale de la "Trans-North China Belt". Ce travail témoigne qu'au Paléoprotérozoïque, une chaîne de collision de type moderne peut se former, avec notamment le développement de chevauchements de type Alpin, suggérant une lithosphère continentale au comportement rhéologique proche de l'actuel.

The co-evolution of life and the environment stands as a cornerstone in Earth's 4.5-billion-year history. Environmental fluctuations have wielded substantial influence over biological evolution, while life forms have, in turn, reshaped Earth's surface and climate. This dissertation centers on a critical period in Earth's history—the Neoproterozoic Era—when profound environmental shifts potentially catalyzed pivotal eukaryotic evolutionary events. By delving deeper into Neoproterozoic paleoenvironments, I aim at a clearer understanding of life-environment co-evolution in this crucial era. The first chapter focuses on an important juncture—the transition from prokaryote to eukaryote dominance in marine ecosystems during the Tonian Period (1000 Ma to 720 Ma). To assess whether the availability of nitrate, an important macro-nutrient, played a critical role in this evolutionary event, nitrogen isotope compositions (δ¹⁵N) of marine carbonates from the early Tonian (ca. 1000 Ma to ca. 800 Ma) Huaibei Group in North China were measured. The data indicate nitrate limitation in early Neoproterozoic oceans. Further, a compilation of Proterozoic sedimentary δ¹⁵N data, together with box model simulations, suggest a ~50% increase in marine nitrate availability at ~800 Ma. Limited nitrate availability in early Neoproterozoic oceans may have delayed the ecological rise of eukaryotes until ~800 Ma when increased nitrate supply, together with other environmental and ecological factors, may have contributed to the transition from prokaryote-dominant to eukaryote-dominant marine ecosystems. Recognizing the spatial and temporal variations in Neoproterozoic oceanic environments, the second chapter lays the groundwork for a robust stratigraphic framework for the early Tonian Period. Employing the dynamic time warping algorithm, I constructed a global stratigraphic framework for the early Tonian Period using δ¹³C_carb data from the North China, São Francisco, and Congo cratons. This exercise confirms the generally narrow range of δ¹³C_carb fluctuations in the early Tonian, but also confirms the presence of a negative δ¹³C_carb excursion of notable magnitude (~9 ‰) at ca. 920 Ma in multiple records, suggesting that it was global in scope. This negative excursion, known as the Majiatun excursion, is likely the oldest negative excursion in the Neoproterozoic Era and marks the onset of the dynamic Neoproterozoic carbon cycle. Shifting focus to the late Neoproterozoic, the third chapter delves into the origins of Neoproterozoic superheavy pyrite, whose bulk-sample δ³⁴S values are greater than those of contemporaneous seawater sulfate and whose origins remain controversial. Two supervised machine learning algorithms were trained on a large LA-ICP-MS pyrite trace element database to distinguish pyrite of different origins. The analysis validates that two models built on the co-behavior of 12 trace elements (Co, Ni, Cu, Zn, As, Mo, Ag, Sb, Te, Au, Tl, and Pb) can be used to accurately predict pyrite origins. This novel approach was then used to identify the origins of pyrite from two Neoproterozoic sedimentary successions in South China. The first set of samples contains isotopically superheavy pyrite from the Cryogenian Tiesi'ao and Datangpo formations. The second set of samples contains pyritic rims from the Ediacaran Doushantuo Formation; these pyrite rims are associated with fossiliferous chert nodules and do not have superheavy sulfur isotopes. For the superheavy pyrite, the models consistently show high confidence levels in identifying its genesis type, and three out of four samples were inferred to be of sedimentary origins. For the pyritic nodule rims, the models suggest that early diagenetic pyrite was subsequently altered by hydrothermal fluids and therefore shows mixed signals. The third chapter highlights the importance of pyrite trace elements in deciphering and distinguishing the origins of pyrite in sedimentary strata. / Doctor of Philosophy / Understanding how life and the environment have shaped our planet's story over 4.5 billion years is like piecing together an intricate puzzle. On the one hand, changes in the environment kickstarted big shifts in how life evolved. On the other hand, living creatures have also left their mark on Earth's landscapes and climate. This dissertation focuses on unraveling the mysterious Neoproterozoic Era (1 billion to 538 million years ago), a time when Earth saw some of its most dramatic changes. A significant aspect of my investigation delves into the evolutionary dynamics within ancient marine ecosystems. Specifically, I'm exploring a critical juncture when organisms with more complex cellular structures, known as eukaryotes, became ecologically more important than prokaryotic life forms in many aspects of Earth systems. By examining ancient rock formations from China, I have found evidence suggesting that nitrate, a vital nutrient, was scarce in the Neoproterozoic oceans. However, around 800 million years ago, there appears to have been a significant surge in nitrate availability. This surge potentially catalyzed a pivotal phase in evolution, possibly driving the shift from prokaryote to eukaryote dominance in these ancient waters. Second, there is a challenge to delineate a robust timeline for the early Neoproterozoic Era. Imagine trying to piece together a story from a time when there were no calendars or clear dates. Employing advanced statistical methods and comparing chemical signals preserved in carbonate rocks from disparate global locations, I endeavor to craft a coherent timeline for this crucial period. Within this timeline, a noteworthy anomaly in the carbon cycle emerged around 920 million years ago known as the Majiatun excursion. This anomaly represents a significant shift in the Neoproterozoic carbon cycle. Furthermore, my investigation plunges into the geochemistry of sulfur, an important element in shaping ancient marine environments. Certain sedimentary rocks harbor anomalous sulfur isotope signatures in the mineral pyrite (also known as fool's gold), hinting at dramatic environmental transformations during the late Neoproterozoic. Employing advanced analytical techniques and machine learning methodologies, I seek to discern the origins and implications of these anomalous sulfur isotope signals found in pyrite, unraveling their significance in reconstructing the environmental dynamics of ancient oceans.

Pour mieux comprendre le processus géodynamique qui a permis la destruction du craton Nord Chinois (NCC), le rôle des fluides mantelliques a été examiné. Pour cela, les distributions des teneurs en eau et des compositions isotopiques du Lithium dans le manteau lithosphérique NCC ont été déterminées à partir des xénolites de péridotite entrainés par les basaltes mésozoïques et cénozoïques. Une variation temporelle des teneurs en eau est observée. Le manteau lithosphérique cénozoïque est appauvri en eau, sans doute suite à l'amincissement crustal et au réchauffement du manteau résiduel par un flux ascendant asthénosphérique. Le manteau lithosphérique mésozoïque montre des teneurs en eau intermédiaire entre les teneurs élevées du Crétacé et les teneurs basses cénozoïques, indiquant une déshydratation du manteau commençant dès le début de sa destruction. Cette déshydratation, facilitée par la destruction du manteau lithosphérique profond, permet de renforcer la rigidité de la lithosphère et lui permet de résister à la convection mantellique. Les distributions élémentaire et isotopique du Li montrent une grande hétérogénéité, aux échelles intra et inter-cristallines. Par simulation numérique, nous démontrons que deux enrichissements successifs ont affecté le manteau, un enrichissement limité (<5ppm) avec une signature pauvre en 7Li ([delta]7Li ~ -20 [pour mille]), suivi d'un enrichissement important (> 100 ppm) avec une signature riche ([delta]7Li ~ +20 [pour mille]), précédent de peu l'exhumation des xénolites. La formation des liquides métasomatiques responsables de ces enrichissements nécessite une distribution hétérogène dans le manteau NCC d'éléments recyclés lors de la subduction à l'est du NCC / In order to investigate the geodynamic cause for destruction of the North China Craton (NCC), the role of mantle fluids is examined. The aim of the PHD work is to clarify H2O contents and lithium isotopic compositions of the NCC lithospheric mantle by studying peridotite xenoliths hosted by Mesozoic-Cenozoic basalts across eastern NCC. A temporal variation of H2O content has been revealed, and it has deep implications for processes of craton destruction. The Cenozoic lithospheric mantle was featured by low H2O content, interpreted to be the relict mantle that survived the lithospheric thinning and has been dewatered by reheating from upwelling asthenospheric flow. The late-Mesozoic lithospheric mantle showed relatively high H2O content, a hydrous status intermediate between the Cretaceous hydration and the Cenozoic dryness, indicating the dehydration of the NCC mantle with time during NCC destruction. The dehydration, facilitated by thinning of weak mantle pieces at bottom, is one way by which the lithosphere strengthens itself to survive in the convecting mantle. Extreme Li and isotopic disequilibria were observed intra- and inter-mineral in the peridotites. With numerical simulations, we demonstrate two superimposed Li enrichment events occurring at the mantle: a limited Li enrichment (< 5 ppm) and large delta7Li depletion (-20~-10[per 1000]) of the mantle domain, followed by a recent and transient infiltration of high Li and delta7Li (up to +20 [per 1000]) melts/fluids. The anomalous Li isotopic compositions of mantle metasomatic agents call upon the same of their mantle sources, and we assume recycled components, both Li isotopically heavy and light, in the mantle beneath the eastern NCC