Google Maps and Google Earth are very common platforms today to explore maps and satellite images of the earth. But there are many other ways to explore the earth. Some are listed here. 1. Earth Explorer This map is developed by USGS helpful to obtain earth imagery across available geo-spatial data types. Users can navigate via interactive map or text search to obtain Landsat satellite imagery, Radar data, UAS data, digital line graphs, digital elevation model data, aerial photos, Sentinel satellite data, some commercial satellite imagery including IKONOS and OrbView3, land cover data, digital map data from the National Map, and many other datasets. Users can search by exact location via the interactive map or input specific coordinates to view what data types are available. 2. Sentinel Hub This platform developed by Sinergise has Sentinel, Landsat, and other Earth observation imagery easily accessible for browsing, visualization and analysi...
Himalaya was formed by the collision of Indian Plate with Eurasian Plate around 55 million years ago.
The major events in the geological history of Himalaya are well recognizable in Nepalese sector. They are: Sedimentation in the Purana Sea, Pan African Diastrophism, Sedimentation in Paleothethys, Hercynian Diastrophism, Gondwana Sedimentation, Sedimentation in Neotethys, beginning of Himalayan Orogeny, formation of foreland basin and tremendous rise of Himalaya
A. Precambrian Events
•Deep and Shallow marine sedimentation in Purana Sea.
•Wide distribution of Precambrian rocks in LH and HH.
•Very early during Paleozoic, there was a very wide sea covering the vast territory of LH and the central and northern parts of India.
•Deep marine sedimentation in early phases and shallow marine deposition in later phases dominantly of carbonate succession with stromatolites.
B. Paleozoic Events
•It includes Pan African Diastrophism, Sedimentation in Paleothethys, breaking of sedimentation due to Hercynian Diastrophism and Early Gondwana Sedimentation
•Pan African Diastrophism: long cycle of Purana Sedimentation came to end towards the close of early Cambrian, sea was forced to recede form LH and sedimentation was interrupted. Intrusion of Cambrian Ordovician granites.
•Sedimentation in Paleothethys: Sedimentation was restarted in Tethyan Himalayan zone with abundant marine fossils of barchipods, corals graptolites etc.
•Hercynian Diastrophism: Interruption of sedimentation in TH (regional unconformity). Rifting and volcanism in LH and widespread glaciation.
•Early Gondwana Sedimentation: at the end of Paleozoic era along with some explosive volcanoes in rift valleys.
C. Mesozoic Events
•Sedimentation in Neotethys and continetal sedimentation of Late Gondwana.
•Sedimentation in Neotethys: Tibetan landmass in North was broken away due to rifting and opened new sea called Neotethys between India and Tibet. Deep marine sedimentation in northern part excluding Nepal Himalaya.
•Sedimentation of Late Gondwana: continental sedmentaion of Upper Gondwana unconfromably over Lower Gondwana.
D. Cenozoic Events
•Disappearance of Neotethys: due to plate collision emplacement and squeezing of sea floor rocks. Formation of elongated basins in North and south and rise of Himalaya.
•Formation of MCT about 21 Ma. Around 25 to 15 Ma Granites and migmatites in TH and HH. Also development of Nappe and Klippe.
•Formation of MBT about 18 to 20 ma and Siwalik Basin.
•Formation of HFT, Dun Valley and Terai basin.
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