| So far, more than 40, 000 meteorites have been recovered all around the world, including only 33 martian meteorites. GRV(Grove Mountains)99027 was collected from blue ice area of Grove Mountains in Southeast Antarctica by 16th Chinese National Antarctic Research Expedition in 1999-2000. It is the first martian meteorite found in Antarctica by our country, and belongs to rare lherzolitic shergottites(L-S, only seven in number).GRV 99027 has petrographic characteristics of poikilitic, non-poikilitic and melt pocket textures and had experienced higher shock metamorphism(S4, 30～45 G Pa, post-shock temperature probably is lower than 600℃) represented by undulose extinction of olivine and pyroxene, parallel planar fracture of olivine, maskelynization of plagioclase and local shock melt pocket. Its weathering stage is W1. Mineralogical modal assembladge of GRV 99027 is: olivine(55 vol%), pyroxene(37.5 vol%) and minor maskelynite(6 vol%), chromite and ilmenite(1.5 vol%), and trace whitlockite, troilite etc. Mineralogical chemical compositions are considerably homogeneous: olivine(Fo69.1-76.6Fa23.4-30.9, avg. Fo72.4Fa27.6), low-Calcium pigeonite( En59.3-75.1Fs20.5-26.9Wo3.1-14.9, avg. En68.6Fs23.5Wo8.0 ) , high-Calcium augite(En46.6-53Fs13.1-16.1Wo31.9-37.8, avg. En50.7Fs14.5Wo34.8), maskelynite(An43.6-59.3Ab40.2-54.6Or0.5-1.8,avg. An52.4Ab46.7Or0.8), homogenous phosphates, Al-, Mg-, and Fe-enriched chromite, Ca-, Fe-, Mg-, and Al-enriched basaltic glass and olivine crystallites with strong chemical zoning located in shock melt pockets, olivine, pyroxene and maskelynite have no chemical zoning. In GRV 99027, three pyroxene thermometry indicates equilibrium temperature of crystallization is about 1000～1190℃(～1146℃). Chemical composition of GRV 99027 whole-rock calculated based on mineralogical modal assembladge is relatively accordant with martian average chemical composition and those of other Lherzolitic-Shergottites, its differentiation index(Fe/(Fe+Mg) 0.27) is also consistent with those of Mars(0.25) and Lherzolitic-Shergottites(0.29～0.30).The REE patterns of minerals and LREE-depleted whole-rock of GRV 99027 are same to those of other Lherzolitic-Shergottites ALHA 77005, LEW 88516, and Y 793605, but olivine and pyroxene of GRV 99027 exhibit negative Ce anomaly(δCe, 0.32～0.71),so terrestrial weathering took place after this meteorite fell into Antarctica.Identical petrography, mineralogical chemistry and REE geochemical characteristics of Lherzolitic-Shergottites agree with a progressive fraction crystallization model of single magmatic reservoir. Olivine and chromite crystallized initially, low-Ca pigeonite formed and poikilitically enclosed cumulus phases, followed by continuous crystallization of augite and then plagioclase, finally more evolved phases such as whitlockite, ulv?spinel, and ilmenite crystallized.Hydrogen isotope of phosphates of GRV 99027:δD +1300～+4700‰, water content 0.04～0.43 wt%,δD has weak negative correlation with water content. HigherδD is consistent with those of other martian meteorites and martian atmosphere, resulted from meteoritic phosphates'isotopical interaction with exchangeable reservoir in martian crust. Intense shock led water content of meteorites to decrease notably. Whole-rock oxygen isotope composition(δ18O 3.97‰±0.07‰,δ17O 2.34‰±0.07‰,△17O 0.28‰) of GRV 99027 is accordant with those of martian meteorites especially Lherzolitic-Shergottites ALHA 77005, LEW 88516, Y 793605, and YA 1075. Oxygen had experienced isotopic mass fraction, resulted from incomplete mixing in solar nebulae during nebular condensation and planetary formation.Mineralogical assembladge, textures, chemical composition, hydrogen and oxygen isotopic compositions, REE contents and patterns of minerals and whole-rock of GRV 99027 are all consistent with those of Lherzolitic-Shergottites ALHA 77005, LEW 88516, Y 793605(as well as GRV 020090, YA 1075, NWA 1950). Moreover, Lherzolitic-Shergottites have identical crystallization and ejection ages, all the evidence indicate that probably they originated from same geological unit of Mars, and were excavated and ejected from Mars by the same shock event.Sr, Nd, Pb and Os isotopic data and REE patterns of martian meteorites imply that there are four different martian reservoirs on Mars: a crust reservoir reprented by Shergotty, one mantle reservoir reprented by L-S(and include B-S EETA 79001),another mantle reservoir reprented by DaG 476, and third mantle reservoir represented by Nakhlite and Chassigny Group. Sr, Nd, Pb and Os isotopic compositions of Lherzolitic-Shergottites ALHA 77005, LEW 88516, Y 793605 are very consistent(ISr 0.71026～0.71052,εNd(T)=+8.2～+14.9,μ<5～5,γOs(0)～+4), they originated from a identical martian mantle reservoir which GRV 99027 also originated from, GRV 99027 experienced same magmatic activities as other L-S meteorites did.According to major, trace element and radiogenic isotopic systems of Lherzolitic-Shergottites, formation process of GRV 99027 was summaried as follows:(1)Initial solar nebulae accreted continuously into Mars.～4.5 Ga ago, Mars happened initial global differentiation, magmatic ocean crystallized quickly and differentiated into different source regions(.2)Mantle source region of L-S(also source region of EETA 79001) partially melted into parent magma, and crystallized Lherzolitic-Shergottites meteorites at～180 Ma ago. (3)Asteroidal body collided with Mars, intense impact excavated Lherzolitic-Shergottites and ejected them from Mars(～4 Ma). They experiended relatively long exposure to cosmic ray, finally trapped by the terrestrial orbit and fell onto different ice-cap in Antarctica. (4)GRV 99027 fell in Grove Mountains in Antarctica, and suffered weathering alteration to some extent.
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