A comparison of three gravity inversion methods for crustal thickness modelling in Tibet plateau

Crustal thickness can be determined by gravimetric methods based on different assumptions, e.g. by isostatic hypotheses. Here we compare three gravimetric inversion methods to estimate the Moho depth. Two Moho models based on the Vening Meinesz-Moritz hypothesis and one by using Parker-Oldenburg’s algorithm, which are investigated in Tibet plateau. The results are compared with CRUST2.0, and it will be presented that the estimated Moho depths from the Vening Meinesz-Moritz model will be better than the Parker-Oldenburg’s algorithm.     

Locating the Melody of the Drives

Psychoanalysis has profoundly influenced those social theories that inform qualitative methodology in human geography. Yet many geographers are skeptical about the value and viability of psychoanalytic methodology because of its alleged reductionist causal explanations and relativistic interpretations of data. Drawing on the work of Slavoj ?i?ek, which affirms Jacques Lacan's undermining of the dualism of causality versus sense, this article illustrates the potential value of Lacanian psychoanalysis as a qualitative methodology in geography. Using a methodological case study from my research on Jamaican tourism, I illustrate how we can locate a Lacanian understanding of the drives in the interactions between tourists and hotel workers. In so doing, the article provides new insights into the enduring allures of tourism's commodity-form by focusing on how the object petit a—a chimerical object that incites desire and an unattainable object that the drives encircle—takes place in customer service and entertainment activities.     

The evolving agricultural landscape of post-plantation Hawai‘i

Hawai‘i's agricultural landscape was previously dominated by large monocrop plantations of sugar cane and pineapple, but following a sweeping series of plantation closures beginning at the end of the twentieth century, that era has concluded. The last spatial assessment of Hawai‘i's agricultural footprint was completed in 1980, during the active plantation period. Here we present the results of a 2015 statewide assessment of the commercial crop footprint for Hawai‘i, based on World-View 2 satellite imagery and supporting datasets. We analyzed changes relative to the 1980 baseline on both a statewide and regional basis, to better understand how Hawai‘i's agricultural system has evolved in the post-plantation era. Sugar cane and pineapple saw dramatic reductions during this period, collectively losing more acres (257,000) than were planted for all crops combined (152,000) in 2015. Idle plantation lands and past plantation-era investments in irrigation and other infrastructure have created opportunities for other types of agriculture, despite rising land values, new and existing tropical diseases, and other challenges. Seed crops, primarily for genetically modified corn trials, were the second largest crop in 2015 (24,000 acres) despite having no mapped footprint in 1980. Commercial forestry, also absent in 1980, covered 23,000 acres in 2015. Macadamia nut, coffee, and diversified agriculture also all saw significant gains in their footprints, with coffee plantings increasing >250% during this period. Despite these gains, the Hawaiian Islands continue to have an extremely low degree of self-reliance for food production. The Oahu plain, adjacent to the major population center of Honolulu, has the most potential for considerably increasing the production of local produce, but without changes in consumption patterns and significant efforts to protect agricultural land from development, any increases in local food production will continue to be incremental. The post-plantation agricultural landscape in Hawaii is smaller, more diversified, and more nimble than it was in 1980, reflecting inter-island geographic differences in land use, history, and ownership. Mapping and assessing spatial changes in agricultural activity over time can provide valuable insights for decision-makers and communities as they continue to define what agriculture should look like in the post-plantation era. Our results suggest that Hawai‘i's agricultural landscape and overall production capability will continue to contract without substantial changes in policy and practice.     

广东博罗县小金河植物区系研究

本区计有野生维管束植物１７２科、５３２属、９７８种（包括变种、变型）。发现２新种，１新变种和３个广东新记录种。本区系的表征科为山茶科、壳斗科、桑科、芸香科、紫金牛科、樟科等，这些科大都是热带－亚热带分布式的，代表了本区系的性质。在属的地理成分中，本区以热带成分１７３属（占总数的３５．２％）和热带－亚热带成分１６９属（占总数的３４．４％）为主，说明了本区系具有由亚热带向热带过渡的南亚热带特征。本区与     

Simion Mehedinţi's Contribution to Modern Romanian Geography

Armed with a scholarship to find an answer to the question “What is geography?” Simion Mehedin?i's studies took him to continental Europe's three main centers of geographic thought: Paris, Berlin, and Leipzig. We explore how his innovative ideas flourished, especially in Leipzig under Ratzel. The first Romanian geographer, Mehedin?i, must be credited with having defined geography as a science of mutual relationships between geospheres. This thinking reached its pinnacle in two complex books, Terra and Ethnos, the contents of which we synthetically explore. We also trace the unfavorable historical and geopolitical conditions that led to this pioneering work being little recognized worldwide.     

LAND–USE CHANGES AND CONSERVATION OF THE HAWAI‘I ‘AMAKIHI

Hawai‘ian honeycreepers have undergone widespread extinction and population declines due to human disturbances, including habitat fragmentation, introduced predatory mammals, alien competitors, and introduced avian diseases. The Hawai‘i ‘amakihi (Hemignathus virens) is one of seven extant Hawai‘ian honeycreepers that, like all other native honey‐creepers, vanished from the low‐elevation native forests on the island of Hawai‘i due to these disturbances. But recent observations indicate that ‘amakihi have begun to recolonize low‐elevation forests in eastern Hawai‘i. In this article we discuss the current abundance of Hawai‘ian ‘amakihi in a suburban habitat on the island of Hawai‘i. We also examine the ‘amakihi's relative preference for native or exotic vegetation. Recolonization in low‐elevation habitats underscores the importance of the remaining native forests. However, concurrent with this recolonization, eastern Hawai‘i is undergoing a residential building boom that has resulted in increased deforestation and forest fragmentation. Thus the future of honeycreepers is uncertain, given the widespread environmental changes taking place in eastern Hawai‘i.     

基于ArcSDE+Oracle 9i的防洪减灾综合数据库的构建及应用

以长江荆江河段防洪预警公共信息平台的防洪减灾综合数据库为例,分析了防洪减灾综合数据库的一般要求及应用特点,介绍了基于ArcSDE+Oracle 9i技术的防洪综合数据库的框架体系和技术思路,并就水利防洪减灾综合数据库的分类、数据库的逻辑设计和存储设计方面的一些细节问题进行了阐述。     

Sedimentary evidence of prehistoric distant-source tsunamis in the Hawaiian Islands

Over the past 200 years of written records, the Hawaiian Islands have experienced tens of tsunamis generated by earthquakes in the subduction zones of the Pacific ‘Ring of Fire’ (for example, Alaska–Aleutian, Kuril–Kamchatka, Chile and Japan). Mapping and dating anomalous beds of sand and silt deposited by tsunamis in low-lying areas along Pacific coasts, even those distant from subduction zones, is critical for assessing tsunami hazard throughout the Pacific basin. This study searched for evidence of tsunami inundation using stratigraphic and sedimentological analyses of potential tsunami deposits beneath present and former Hawaiian wetlands, coastal lagoons, and river floodplains. Coastal wetland sites on the islands of Hawai΄i, Maui, O΄ahu and Kaua΄i were selected based on historical tsunami runup, numerical inundation modelling, proximity to sandy source sediments, degree of historical wetland disturbance, and breadth of prior geological and archaeological investigations. Sand beds containing marine calcareous sediment within peaty and/or muddy wetland deposits on the north and north-eastern shores of Kaua΄i, O΄ahu and Hawai΄i were interpreted as tsunami deposits. At some sites, deposits of the 1946 and 1957 Aleutian tsunamis are analogues for deeper, older probable tsunami deposits. Radiocarbon-based age models date sand beds from three sites to ca 700 to 500 cal yr bp , which overlaps ages for tsunami deposits in the eastern Aleutian Islands that record a local subduction zone earthquake. The overlapping modelled ages for tsunami deposits at the study sites support a plausible correlation with an eastern Aleutian earthquake source for a large prehistoric tsunami in the Hawaiian Islands.     

胶东晚中生代金矿成矿的硫同位素组成及热动力源

胶东地区晚中生代金矿床均有一个与岛弧玄武质、安山质岩浆相一致的δ^34(6．5‰-7.0‰)硫源，而全铜矿床的δ^34为4．5‰-5．0‰，与岛弧玄武质岩浆的δ^34接近。可初步认为该区全(铜)成矿流体的热源来自地慢或俯冲地慢楔产生的玄武岩浆。成矿流体的产生与岛弧玄武质岩浆底侵／内侵作用密切相关，形成于被加热的地壳。     

GEOLOGICAL EVOLUTION AND OROGENY OF EAST KUNLUN TERRAIN ON THE NORTHERN QINGHAI—TIBET PLATEAU

GEOLOGICAL EVOLUTION AND OROGENY OF EAST KUNLUN TERRAIN ON THE NORTHERN QINGHAI—TIBET PLATEAU1　XuZQ ,YangJS ,ZhangJX ,etal.AcomparisonbetweenthetectonicunitsonthesidesoftheAltunsinistralstrike slipfaultandthemechanismoflithosphericshearing[J] :ActaGeologicaSinica,1999,73:193～ 2 0 5(inChinesewithEnglishabstract) . 2　YangJS ,XuZQ ,LiHB ,Wu ,etal.DiscoveryofeclogiteatthenorthernmarginofQaidambasin,NWChina[J] .Chi neseScienceBulletin,1998,4 3…