At a coarse level of time resolution, episodes of speleothem growth record relatively wet periods in semi-arid climates or relatively warm periods in cool temperate climates.
Speleothem use in Paleoclimatic Study Read More »
The Redfield ratio is the consistent atomic ratio of carbon, nitrogen and phosphorous found in marine phytoplankton and throughout the deep oceans (C:N:P = 106:16:1). When nutrients are not limiting, the molar elemental ratio C:N:P in most phytoplankton is 106:16:1 In the ocean, a large portion of the biomass is found to be nitrogen-rich plankton. Many of these plankton
Quaternary time period is from 1.8 Ma to today, during this time period a lot of climate fluctuations happened which are discussed below :-
Quaternary Climate Read More »
The study of geology offers a captivating journey through time, unveiling the intricate tapestry of Earth’s history. Spanning billions of years, this narrative is composed of distinct epochs, each characterized by unique geological events and transformations. In this article, we delve into the fascinating world of geological time, exploring the epochs that have shaped our
Exploring the Marvels of Geological Time: Unveiling Earth’s Epochs Read More »
As the amount of available data has multiplied over the past ten years, the number of apparently distinct reservoirs has risen from two (primitive and depleted mantle, respectively) to five (PREMA, Depleted, HIMU = high U/Pb and Two types of EM or enriched mantle reservoirs). The depleted reservoir produces “normal” (N-type) MORB probably more than
Mantle Reservoirs Read More »
Anorthosites are defined as plutonic rocks with over 90% plagioclase. They are highly felsic, felsic minerals, however is a Calcic plagioclase, which along with subordinate associated high temperature mafic minerals. The anorthosites can be classified as Archaean and Proterozoic – Archaean Anorthosites :- Most Archaean anorthosites cluster in the range 3.2 to 2.8 Ga. They
An oceanic core complex or magnalium is a seabed geological feature that forms a long ridge perpendicular to a mid-oceanic ridge. It contains smooth domes that are lined with transverse ridge like a corrugated roof. They can vary in size from 10 to 150km in length, 5 to 15 km in width, and 500 to
Oceanic Core Complex Read More »
An ancient landform or landscape that had been buried beneath younger rocks or sediment and that is exposed by their subsequent erosion. This process is called Exhumation. Exhumation refers to any geological mechanisms that brings the rocks from deeper crustal levels to shallower crustal levels. While erosion or denudation is fundamental in eventually exposing these
Exhumed Topography Read More »
Important minerals : Types of chromite deposits :- Indian deposits :- Stratiform or Layered Chromite Associated with mafic/ ultramafic layered intrusions formed in calm environment (Precambrian) Podiform chromite Irregular geometry, found in disturbed environment, Phanerozoic in age Sukinda ultramafic complex, Orissa Stratified beds inclosed in a sequence of Dunite-peridotite Sithampundi chromite, Tamilnadu Stratiform deposit in
Chromium (Cr) Deposits Read More »
Important minerals : Type of Deposits : Indian Deposits :- Andhra Pradesh Kodurite Kalahandi and Koraput Precambrian iron ore series
Manganese (Mn) Deposits Read More »
