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the Himalaya in the Hazara syntaxis,
Pakistan, the youngest marine sediments
correspond to nummulite-bearing limestones
of the shallow benthic zone
SBZ10 and planktonic foraminifera P7
zone (52-51 Ma). The timing of closure
of Neo-Tethys between India and Asia
corresponds closely to the ending of
subduction-related granodiorite-granite
magmatism along the Ladakh-Gangdese
batholith ( southern, Andean-type margin
of the Asian plate) and precedes the
drastic slowing of the northward drift of
India. Continental fluvial-deltaic red
beds unconformably overlie all marine
sediments, both in the suture zone and
along the north Indian plate margin.
2010010560
地 中 海 中 西 部 阿 尔 比 斯 地 区 中 三 叠 统 -
下 侏 罗 统 大 陆 红 层 沉 积 演 化 的 组 成 和
地 球 化 学 特 征 = Compositional and
geochemical signatures for the sedimentary
evolution of the Middle Triassic-
Lower Jurassic continental redbeds from
western-central Mediterranean Alpine
chains. ( 英 文 ). Critelli S; Mongelli G;
Perri F; Martin A A; Martin M M; Perrone
V; Dominici R. Journal of Geology,
2008, 116(4): 375-386
Compositional and chemical analyses
suggest that Middle Triassic-Lower Liassic
continental redbeds ( in the internal
domains of the Betic, Maghrebian, and
Apenninic chains) can be considered a
regional lithosome marking the Triassic-
Jurassic rift-valley stage of Tethyan rifting,
which led to the Pangaea breakup
and subsequent development of a mosaic
of plates and microplates. Sandstones
are quartzose to quartzolithic and represent
a provenance of continental block
and recycled orogen, made up mainly of
Paleozoic metasedimentary rocks similar
to those underlying the redbeds. Mudrocks
display K enrichments; intense
paleoweathering under a hot, episodically
humid climate with a prolonged
dry season; and sediment recycling.
Redbeds experienced temperatures in
the range of 100 degrees-160 degrees C
and lithostatic/tectonic loading of more
than 4 km. These redbeds represent an
important stratigraphic signature to reconstruct
a continental block (Mesomediterranean
Microplate) that separated
different realms of the western
Tethys from Middle-Late Jurassic to
Miocene, when it was completely involved
in Alpine orogenesis.
2010010561
西 藏 南 部 橄 榄 玄 粗 岩 记 录 晚 侏 罗 世 古
特 提 斯 洋 内 岛 弧 裂 解 = Shoshonites in
southern Tibet record Late Jurassic rifting
of a Tethyan intraoceanic island arc.
( 英 文 ). Aitchison J C; McDermid I R C;
Ali J R; Davis A M; Zyabrev S V. Journal
of Geology, 2007, 115(2): 197-213
Detailed field mapping combined
with a petrologic and geochemical investigation
of the Zedong terrane within
the Yarlung Tsangpo suture zone provides
insights to the evolution of now
mostly subducted portions of Tethys
during the Late Jurassic. The terrane is
dominated by volcanic rocks of shoshonitic
affinity, which were erupted in
a submarine oceanic island arc setting.
The volcanic island arc was built on a
basement of oceanic crust, and the shoshonites
locally overlie a thin section of
pillowed island arc tholeiites and red
ribbon - bedded radiolarian cherts. Geochemistry
of the shoshonites suggests
that their development occurred in a setting
analogous to that of Late Miocene
to Early Pliocene Fiji and was associated
with an arc rifting. We speculate that
this event may have been a far-field response
to developments associated with
Gondwana breakup.
2010010562
德 克 萨 斯 州 Trans-Pecos 地 区 晚 白 垩
世 火 山 活 动 的 证 据 = Evidence for Late
Cretaceous volcanism in Trans-Pecos
Texas. ( 英 文 ). Breyer J A; Busbey A B;
Hanson R E; Befus K E; Griffin W R;
173