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5篇 您的检索式:作者名="R.J.Thomas"
    题名 作者 年代 出处 被引量
1Multiple origins of charnockite in the Mesoproterozoic Natal belt,Kwazulu-Natal,South Africa显示文摘与形成的不同模式, charnockitic 岩石的四个不同变化从 Mesoproterozoic 出生的带被描述,新 C 同位素数据介绍了。在很多石场和河节的优秀沿海的暴露为观察 charnockitic 地关系使出生的带的这部分成为一个好地点。而 charnockites 的开始和条款 charnockite 的使用上有许多争论,相对在 granitoid 岩石中的黑云母的 orthopyroxene 的稳定是低 aH2O 的功能,这通常被认出(? 瀠獯 ? 慭浧瑡捩 ????? 敲牣獹慴汬獩瑡潩吗?G.H.Grantham P.Mendonidis R.J.Thomas M.Satish-Kumar 2012Geoscience Frontiers2012,3,6:2
2安第斯山坡土壤结皮和密闭对其理化性质的影响显示文摘Thier felder C.E.Amēzquita R.J.Thomas K.Stahr 2002中国水土保持2002,,7:1
3豆科牧草在维系草地丰产的氮循环中的作用显示文摘通过模拟温带和热带地区草地氮循环不同过程的氮流,研究了豆科牧草在不施氮肥的放牧草地氨循环中的作用。对于利用率为10~40%的热带草地来说,在不指望吸收土壤里的有机氮(即无净氮矿化作用)的情况下,据测定,为平衡氮循环,由豆科牧草固定的氮,必须占牧草地上部份含氮量的38~53%,若以干物质(DM)计,则为20~31%。在放牧强度大,利用率较高。达50~70%的温带草地,不施氮肥时,靠豆科牧草固定的氮需达地上部份含氮量的57~67%,或DM的35~45%,对每个有效的再循环过程(粪尿返还、内部循环或枯落物腐烂分解再代谢)的测试表明,内部循环氮的数量变化,对低水平利用(10~40%)草地的生物固氮量有最大的影响,而利用率较高(70%)的草地,为了平衡循环,返还的粪尿氮的变化,对生物固氮量会产生主要影响。就热带草地而言,要保持3~22t·ha^(-1)·年^(-1)的牧草DM产量,所需要的生物固氮量应为15~158kg ha^(-1)·年^(-1)。集约经营的温带草地,要维持含氮量3.5%的DM产量6~15t ha^(-1)·年^(-1),需要的固氮量为120~352kg ha^(-1)·年^(-1)。这些拟态量表明,豆科牧草在牧草干物质中所占的比例达20~45%,就能维系温带和热带草地的丰产(就N_2而言)。R.J.Thomas 杜修贵 1993四川草原1993,,3:1
4A continental back-arc setting for the Namaqua belt:Evidence from the Kakamas Domain显示文摘A study of the NW Kakamas Domain in South Africa/Namibia provides a new,unified lithostratigraphy and evolutionary history applicable to the whole Namaqua Sector.The Mesoproterozoic history ranges from~1350 Ma to 960 Ma,but isotopic evidence suggests it was built upon pre-existing Paleoproterozoic continental crust that extended west from the Archaean Craton.In eastern Namaqualand,early rift-related magmatism and sedimentation at~1350 Ma occurred in a confined ocean basin.Subsequent tectonic reversal and subduction at~1290–1240 Ma led to establishment of the Areachap,Konkiep and Kaaien Domains.In the Kakamas Domain,widespread deposition of pelitic sediments occurred at~1220 Ma(Narries Group).These contain detrital zircons derived from proximal crust with ages between~2020 Ma and 1800 Ma(western Palaeoproterozoic domains)and 1350–1240 Ma(eastern early Namaqua domains),suggesting pre-sedimentation juxtaposition.The pelites underwent granulite grade metamorphism at~1210 Ma(peak conditions:4.5–6 kbar and 770–850°C),associated with voluminous,predominantly S-type granitoid orthogneisses between~1210 Ma and 1190 Ma(Eendoorn and Ham River Suites)and low-angle ductile(D_(2))deformation which continued until~1110 Ma,interspersed with periods of sedimentation.This enduring P-T regime is inconsistent with the expected crustal over-thickening associated with the generally-accepted collision-accretion Namaqualand model.Rather,we propose the Namaqua Sector is a‘hot orogen’developed in a wide continental back-arc with subduction west of the present-day outcrop.The observed high geotherm resulted from thinned back-arc lithosphere accompanied by an influx of mantle-derived melts.Ductile D_(2)deformation resulted from'bottom-driven'tectonics and viscous drag within the crust by convective flow in the underlying asthenospheric mantle.This extended tectonothermal regime ceased at~1110 Ma when SW-directed thrusting stacked the Namaqua Domains into their current positions,constrained in the Kakamas Domain by late-to post-tectonic I-type granitoids intruded between~1125 Ma and 1100 Ma(Komsberg Suite).The thermal peak then shifted west to the Bushmanland and Aus Domains,where voluminous granites(1080–1025 Ma)were associated with high-T/low-P granulite facies thermal metamorphism and mega-scale open folding(D_(3)).Unroofing of the Namaqua Sector is marked by large-scale,NW-trending,sub-vertical transcurrent dextral shear zones and associated pegmatites and leucogranites at~990 Ma.P.H.Macey R.J.Thomas A.F.M.Kisters J.F.A.Diener M.Angombe S.Doggart C.A.Groenewald C.W.Lambert J.A.Miller H.Minnaar H.Smith H.F.G.Moen E.Muvangua A.Nguno G.Shifotoka J.Indongo D.Frei C.Spencer P.le Roux R.A.Armstrong C.Tinguely 2022Geoscience Frontiers2022,13,4:0
5豆科植物对持续热带草地系统的供氮作用显示文摘一、引言 世界总面积的23%或34亿hm^2是永久性草地(FAO,1993),这些草地约有15亿hm^2属于野生或栽培。在大多数热带发展中国家,草地的牲畜生产量较发达国家为低。以牛肉生产量为例,发展中国家每年每头牲畜约为20kg,而发达国家则为96kg(Henzell,1983)。有人认为在南美、非洲、亚洲和澳大利亚。R.J.Thomas 魏昭林 1996国外畜牧学(草原与牧草)1996,,3:0
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