Wednesday, August 31, 2022

LInks: India Aquifers, Early Bipedalism, Mars Geology

 Here are some interesting articles I read recently.

1) Mapping India's Aquifers.  Indian agriculture depends heavily on groundwater. To understand and manage this resource we need a good idea of the nature and extent of aquifers. Subodh Yadav, Joint Secretary, Department of Water Resources, River Development and Ganga Rejuvenation, Ministry of Jal Shakti, has written an informative article on the National Aquifer Mapping Program. Detailed reports are available to the public through the Central Ground Water Board, Aquifer Information and Management System page. Mapping and report availability is still work in progress.

2) Is Sahelanthropus the earliest biped? A good article by Brian Handwerk on the many questions spawned from a recent analysis of a 7 million year old femur fossil. Fossil remains named Sahelanthropus tchadensis were found nearly 20 years ago in Chad, and various studies have come to conflicting conclusions on whether Sahelanthropus could walk on two legs. Bipedalism is considered to be one of the key traits distinguishing members of the human branch from other apes and so there is a vital interest in understand the timing and circumstances of its evolution. 

3) Ground Penetrating Radar images from Mars Perseverance Rover. The indefatigable Mars Rover loaded with geological instruments is currently exploring the edge of the Jezero Crater on Mars. Here, rivers emptied into a large lake depositing sediment and building a delta. The first radar images show inclined sedimentary layers which could be the classic sign of a delta architecture or something else, scientists suspect. Read on! By Holly Ober, University of California, Los Angeles.

Friday, August 12, 2022

Readings: Deep Time Mexico, Neanderthals, Early Mammals

Relish these articles.

1) Mexico City Deep Time Sickness.  Modern day Mexico City is built on the bed of lakes that formed around 2 million years ago. The Mexica people in the 14th century constructed a series of dams and dykes partitioning salt water and fresh water areas. They developed agriculture called as 'chinampas' on islands made up of mud and organic debris. This region became the city state of Tenochtitlan. Later in the 16th century this vast lake was drained by Spanish Conquistadors. Over time, extraction of groundwater is causing compaction of the soft sediment. The ground is subsiding unevenly across different parts of the city. Ground shaking by frequent earthquakes is making the problem worse. As cracks grow and widen, buildings tilt, and the ground shakes, the citizens have become acutely sensitive or "tocado" to geology altering their everyday lives.

"Deep time is often framed as something antithetical to immediacy, something totally separate not only from everyday experience, but also the idea of history itself. But if we are living in a moment in which experiential time, historical time and deep time are colliding, which of these times are being written onto the walls of Mexico City apartments?

A beautiful and unnerving article by Lachlan Summers.

2) Did Neanderthals Speak? Archaeologist Anna Goldfield summarizes our current state of understanding of the throat anatomy of Neanderthals and how they might have sounded. There is a nice audio clip too! 

3) Warm Blooded Mammals. When did warm bloodedness or endothermy evolve in mammals? Katherine Irvine writes about a new study of ear canal bone structures indicative of endothermy. An analysis of fossils suggest that warm bloodedness, along with a host of traits typically associated with mammals, arose by around 233 million years ago.