Systems Theory in Physical Geography

Information used in systems is organized into a hierarchy of five levels, following W. H. Terjung; first, collected data; second, sets of morphological variables; third, flow systems of energy and matter; fourth, process-form systems; fifth, systems regulated by cybernetic feedback. System variables, rigorously defined by dimensional analysis, are grouped into four classes: A. dynamic variables related to energy force, and stress; B. mass-flow variables expressing rates of flow of matter; C. geometry variables describing size and form within systems; D. material-property variables, including environmental constants and regulator variables. The second level of systems analysis interrelates a set of morphological elements in a meaningful way in terms of system origin or function. Correlation and regression methods establish significant relationships among variables, which may be stated as empirical or rational equations based on field or laboratory observations. Open energy flow systems and open or closed material flow systems of the third level can be described by dimensionally correct equations or by schematic flow diagrams. Process-form systems of the fourth level are characterized by self-regulation through physical feedback loops. Cybernetic feedback characterizes the fifth level and links natural systems to those regulated or disturbed by human intervention.     

Phase Changes in Linear Solar-Terrestrial Relationships and a Review of the Electrification Hypothesis

It appears that relatively strong linear relationships between solar activity and various weather phenomena are forthcoming only if the analyses relate to specific solar periods or are con ducted for specific geographic locations. Solar periods in this instance are defined according to the amplitude of the 11-year sunspot cycle. The sign for correlation coefficients between weather ele ments under investigation and solar activity often change according to solar amplitude. However, these phase changes may not weaken arguments in favor of sun-weather hypotheses.

Atmospheric teleconnection provides a logical explanation for phase changes over space within specific time frames, and variations in solar-amplitude relate to reversals in phase with space held constant. Previous research of large pressure systems in the tropics and mid-latitudes as well as re gional variations in annual precipitation outlined in this research indicate that a change in sign for the linear sun-weather relationship occurred between 1930 and 1940. Between 1930 and 1940, the amplitude of the solar cycle also changed. The incredibly complex nature of the climatic change equation along with the lack of an explicit physical link between solar-activity and the lower atmo sphere are serious deterrents for broad acceptance of a solar-weather connection. It is suggested, however, that recent research on a possible electrical stimulus might go far in establishing the solar hypothesis as a credible one.     

STORAGE OF MINING-RELATED ZINC IN FLOODPLAIN SEDIMENTS,BLUE RIVER,WISCONSIN

This study investigates spatial patterns of sediment-associated zinc (Zn) storage in floodplain deposits and the potential reintroduction of these metal-contaminated sediments to the active channel by bank erosion. We estimate patterns of Zn mass storage by combining longitudinal trends in Zn concentrations with measurements of sediment mass storage in overbank and point-bar deposits. Overbank deposits are the largest contaminant sink, storing five times more Zn than the point-bar deposits. While Zn concentrations decrease downstream because of dilution effects, the total mass of Zn stored in floodplains is greatest in both the upstream reaches and in the wider lower valleys where low channel gradients promote rapid sedimentation. Zn storage is low in middle reaches where steep, narrow valleys with high stream power favor sediment transport over deposition. Overall, more than half of the Zn released by mining remains stored in floodplain deposits within the watershed. The remobilization of Zn from storage is more likely in the upstream and mid-basin reaches where high stream power increases rates of lateral channel migration. Channels in the lower valley lack the stream power to migrate laterally and remobilize the large Zn mass stored in overbank sediments. [Key words: floodplains, Zn contamination, mining, stream power, Wisconsin.]     

Synoptic Classification of Snowfall Events in the Great Smoky Mountains,USA

Mean annual snowfall in the Great Smoky Mountains National Park (GSMNP) exhibits considerable spatial variability, ranging from 30 cm in the valleys to 254 cm at higher elevations. Snowfall can be tied to a variety of synoptic classes (e.g., Miller A or B cyclones, 500 hPa cutoff lows), but the frequency and significance of different synoptic classes have not been fully assessed, particularly at higher elevations. In this paper, we manually classify all snowfall events during the period 1991 to 2004 according to a synoptic classification scheme, calculate mean annual snowfall by 850 hPa wind direction and synoptic class, and develop composite plots of various synoptic fields. Hourly observations from nearby first-order stations and 24 hr snowfall totals from five sites within the GSMNP are used to define snowfall events. NCEP/NCAR reanalysis data are used to develop composite plots of various synoptic fields for cyclones passing south and then east of the area (e.g., Miller A cyclones). Results indicate that over 50% of the mean annual snowfall at higher elevations occurs in association with low-level northwest flow, and that Miller A cyclones contribute the greatest amount to mean annual snowfall at all elevations.     

部分格罗夫山陨石的类型划分及其矿物岩石学特征

对99块南极格罗夫山陨石的研究表明这些陨石分别属于普通球粒陨石H群、L群、LL群,橄辉无球粒陨石和碳质球粒陨石。其中普通球粒陨石H3为1块,H4为23块,H5为9块,H6为8块,L4为2块,L5为21块,L6为31块,LL4和LL6分别为一块。GRV 022888为橄榄石-易变辉石无球粒陨石,GRV 023159是一块CV3碳质球粒陨石。这些陨石的冲击程度普遍较高,冲击程度为S4的普通球粒陨石有15块,GRV 023138中出现了冲击熔融现象,该陨石的冲击程度为S5,这些样品为研究小行星早期的冲击作用提供了很好的素材。此外,这些陨石的风化程度普遍较低,风化程度为W1的陨石为75块,未见风化程度高于W4的陨石。     

东南极格罗夫山：普里兹造山带中一个典型的泛非期变质地体

提要：距我国中山站以南约400 km的格罗夫山是普里兹造山带向南极内陆的延伸部分,其基底地体由约在920?910 Ma期间侵入的镁铁质－长英质火成岩和少量中元古代的沉积岩构成,这些岩石仅在泛非期（约570?500 Ma）经历了单相变质－构造旋回,因此是一个典型的泛非期变质地体。泛非期高峰变质作用并不象前人所认为的那样仅为中低压麻粒岩相,而是高达770?840?C、1.18?1.40 GPa,并在随后经历了近等温减压（约0.6 GPa）的P-T演化过程。大规模的A型紫苏花岗岩和花岗岩在同造山－后造山阶段侵位,并造成了麻粒岩地体近等压降温的P-T轨迹。这些花岗质岩石是由长期富集地幔的底侵物质（碱性玄武质岩石）经部分溶融而形成的。结合相邻地质体的研究资料,我们认为普里兹造山带可能发育在太古宙－格林维尔期基底地体之上,这些基底地体可能与新元古代（？）盖层卷入到了统一的泛非期造山作用过程。在泛非期造山作用过程中,地壳曾被增厚约达40?50 km,而后又经历了厚约20 km的地壳伸展垮塌和剥蚀。所以,普里兹造山带应代表东冈瓦纳陆块内部由板块缝合作用所形成的一条泛非期碰撞造山带。     

中条山同善地区虎坪杂岩锆石U-Pb年龄、Hf同位素特征及地质意义

中条山地区是华北克拉通中部造山带的重要组成部分,区内前寒武纪地层广泛出露,新太古代地质体主要分布在北东走向的中条山主山脉和近东西向王屋山"同善天窗"内。"同善天窗"中主要出露虎坪花岗质片麻杂岩及宋家山群。虎坪杂岩中黑云斜长片麻岩的锆石U-Pb上交点年龄为(2 530±13)Ma,εHf(2 530Ma)为3.89～7.12;英云闪长岩207 Pb/206 Pb加权平均年龄为(2 551.4±2.7)Ma,εHf(t)为5.49～9.67。结合近年来华北克拉通新太古代晚期中部造山带镁铁质火山岩Nd同位素及遵化二辉橄榄岩的Hf同位素特征,推测华北克拉通中部造山带新太古代晚期地幔εHf(t)与εNd(t)具有一定的线性关系,中条山新太古代晚期地幔εHf(2.55Ga)为8.2～9.5,显示华北克拉通地幔在2.55Ga之前即发生过大规模的分异。虎坪变英云闪长岩幔源Hf同位素的特征需要新生玄武质地壳俯冲熔融,类似特征的花岗岩往往存在于洋内俯冲带或是洋脊俯冲的特殊构造环境;因此,虎坪英云闪长岩的产出可能代表了中条山2.55Ga的洋脊俯冲或是年轻洋壳的壳内俯冲事件。     

川西龙门山中段天然硅石资源地质特征及评价

介绍了龙门山中段脉石英、石英砂岩等硅石矿产地质特征,分析其工业应用评价,提出勘查开发利用与保护的意义。     

北淮阳浅变质岩带卢镇关群变质压力及其对大别造山带演化的指示

卢镇关群是北淮阳浅变质岩带的重要组成部分,其俯冲历史对于证明超高压岩石经历了深俯冲及获得完整的大别造山带演化历史具有重要意义.本次工作在霍山牛角冲、与儿街卢镇关群岩石中采集了含石榴子石的黑云二长片麻岩和石榴黑云片麻岩进行电子探针分析,并通过石榴子石—黑云母—斜长石—石英压力计计算获得了卢镇关群的变质压力变化于1.89～1.99 GPa,其平均值为1.94 GPa.根据造山带内中—上地壳岩石的平均密度,获得了卢镇关群曾俯冲于地下64.7 km的深度.这表明位于大别造山带最北缘的北淮阳带曾俯冲于较大深度,支持前人关于华南、华北板块缝合线位于北淮阳带以北的结论.     

利用宽谱系岩墙群进行勘查靶区预测的初步尝试: 以南阿拉套山为例

本文提出了一种利用宽谱系岩墙群(WSDS)进行内生金属矿床勘查靶区预测的新方法。南阿拉套山出露有一套由二叠纪煌斑岩质、玄武质、安山质、英安质和流纹质岩墙(脉)组成的岩墙群,可称为宽谱系岩墙群。该岩墙群侵位于花岗质岩基及其围岩中,是区内最晚一期岩浆活动的产物。以下特征暗示岩墙群的形成伴随着大规模含矿流体活动:(1)许多岩墙岩石具有气孔状构造,且含有大量含水暗色矿物; (2)部分岩墙岩石具有多斑斑状结构,基质为隐晶质或玻璃质结构; (3)部分岩墙岩石含有浸染状硫化物; (4)各类岩墙具有相似的不相容元素和成矿元素分配型式; (5)不同时代、不同岩性的地层具有相似的成矿元素分配形式。因此,宽谱系岩墙群及其围岩经受过含矿流体的浸润和改造,可作为确定性找矿标志。岩墙群的空间展布形式同时受区域性裂隙系统和局部性裂隙系统控制,可以解释为岩墙同时侵位于先存裂隙和自生长裂隙中。因此,宽谱系岩墙群是熔体-流体流快速侵位的产物,具有较强的成矿潜力。岩墙的空间展布形式可能暗示了含矿流体的运移方式,因而可以用来预测成矿金属大规模堆积的可能位置:(1)流体在运移路径上与碳酸盐岩相遇的部位; (2)流体在运移路径上与块状少裂隙火成岩体相遇的部位; (3)流体运移路径上适度破碎的断裂交汇部位; (4)流体在运移路径上与高渗透率地层相遇的部位; (5)岩墙密集区的小岩体。据此,可在南阿拉套山划出为六个勘查靶区(A、夏尔敖腊靶区,B、米尔其克岩体靶区,C、勒根乌苏-科克塔舒根乌苏靶区,D、阿尔夏提靶区,E、布图哈马尔西南岩体靶区,F、诺尔特靶区),涵盖了区域矿产调查发现的20个矿点(床)中的8个。如果将预测靶区的范围稍微扩大,则可以涵盖15个矿点(床)。据此,可以认为利用宽谱系岩墙群进行成矿预测是有效的。